Public evidence page

Rugby union - Tight five

Sport

Sport: Rugby union

Position: Tight five

Athletes' bodies

Elite female rugby union tight five (props + hookers + locks) are optimized for scrummaging and close-contact dominance: high body mass and upper-body leverage for set-piece force generation, stiffness/stability for repeated collisions, and sufficient lean strength to lift/engage in mauls/rucks while still functioning as a mobile part of the scrum unit.

Cohort

Sex: Female

Level: Elite

Quick glossary

Prior: Model estimate before updating with the current evidence; the starting baseline.
Posterior: Model-updated estimate after combining prior evidence with observed data.
Standard deviation: Spread around the estimate; lower means tighter expected range.
Alignment: How well a goal/preference/injury profile matches this body pattern.

Measurements

Factor	Prior	Posterior	Success-impact	Reasoning behind prior	Prior estimate sources
Height	180 ± 5 cm	180 ± 5 cm	high	Tight five is a scrummaging-centered subset of forwards; since elite women’s forwards average ~176 cm, a small upward adjustment (~180 cm) is used to reflect the set-piece stability/tall line-out exposure common in the tight-five bundle (esp. locks), without assuming an all-lock profile.	[1] [2]
Weight	100 ± 11 kg	100 ± 11 kg	high	Tight five requires absolute strength/force tolerance and mass for scrum/maul collisions; therefore weight is set above the forwards mean (~94 kg) to ~100 kg with SD ~11 kg to cover prop vs lock variation.	[1] [2]
Arm span	183 ± 6.5 cm	183 ± 6.5 cm	medium	Set arm span slightly above height to support hand/arm reach during binds, carries, and line-out/contest moments—without assuming extreme limb-length advantage.	[3]
Leg inseam	87 ± 4 cm	87 ± 4 cm	medium	A slightly longer inseam supports stable driving positions (scrum/maul leg force) while maintaining sufficient lower-body robustness for repeated collisions.	[4]
Leg-torso ratio	1.41 ± 0.11 ratio	1.41 ± 0.11 ratio	medium	A balanced leg:torso ratio supports powerful stance mechanics and stable forward driving without producing an overly long/awkward lower-body profile.	[5]
Pelvic bone width	32 ± 2.8 cm	32 ± 2.8 cm	medium	A moderate-to-wide pelvis supports hip bracing and force transfer during scrum binding, ruck-entry angles, and collision landings.	[6]
Shoulder-hip ratio	1.4 ± 0.09 ratio	1.4 ± 0.09 ratio	medium	A moderately high shoulder:hip ratio supports scrummaging leverage and upper-body engagement while still keeping hip breadth sufficient for bracing.	[7]
Shoulder width	44.8 ± 3.3 cm	44.8 ± 3.3 cm	medium	Tight five benefits from broader upper-body leverage for scrummaging and tackling; shoulders are modeled on the broader side of an elite forward without forcing a prop-only or lock-only extreme.	[8]
Torso length	61.5 ± 4.5 cm	61.5 ± 4.5 cm	medium	Mid-to-long torso supports bracing, upright contact posture, and stable upper-body positioning in set-piece mechanics.	[9]
Ankle circumference	23.1 ± 2 cm	23.1 ± 2 cm	low	Tight five undergoes high stance/landing loads; ankle circumference is set slightly robust but treated as low importance versus strength/power and technique.	[10]
Ape index	1.01 ± 0.03 ratio	1.01 ± 0.03 ratio	low	Near-normal ape index is used to avoid assuming extreme reach advantage; tight five benefits from reach but not as a primary determinant compared with strength and stability.	[11]
Foot length	28.2 ± 1.5 cm	28.2 ± 1.5 cm	low	Foot length is modeled consistent with height to support cleat fit and stable scrummaging/stance under load.	[12]
Hand length	19.8 ± 1.1 cm	19.8 ± 1.1 cm	low	Hand length is kept at a realistic adult baseline; tight-five selection is driven much more by mass/strength, technique, and collision tolerance than by hand length.	[13]
Wrist circumference	17 ± 1.5 cm	17 ± 1.5 cm	low	Wrist circumference is only weakly position-discriminative; set to a realistic adult-athlete value.	[14]

Traits

Factor	Value	Impact	Reasoning	Sources
Muscle fiber profile	balanced	high	Set-piece collisions and scrummaging require fast force production, but tight five also repeatedly participates in rucks/mauls and sustained high-intensity phases; therefore balanced repeatability is prioritized.	[15]
Metabolic tendency	endomorphic tendency	medium	Tight five benefits from absolute mass and the ability to maintain strength in high-collision contexts; a mild endomorph prior (mass-retention) is more plausible than an ectomorph-only model, while still assuming elite conditioning.	[16]
Joint laxity	low	high	Low laxity supports stable force transfer in heavy scrummaging loads and repeated collisions, reducing energy “leak” and unwanted joint motion.	[17]
Foot arch	neutral arch	medium	Neutral arch is selected to support stable scrummaging/stance mechanics and reliable force transmission under heavy ground reaction forces.	[18]
Temperature tolerance	balanced	low	Tight five experience hard bursts inside set pieces and frequent collisions, but the overall match context is outdoor/variable; therefore a balanced prior is used.	[19]
Dominant side	no meaningful side advantage	none	Handedness can influence individual technique, but it’s not assigned as a population-level tight-five advantage prior.	[20]

Goals

Factor	Alignment	Reasoning	Sources
Build confidence	medium	Tight five has a clear learning curve (scrum technique, contesting, body control, and contact confidence). As you get better and more technically consistent, confidence tends to rise. But because progress can be slower early on and contact risk can be intimidating, it’s usually medium instead of “very high.”	[21] [22]
Build endurance	medium	Tight five definitely need some endurance because scrums repeat, they work hard across an ~80-minute match, and fatigue affects performance and safety. But the “endurance stimulus” is more intermittent and contact-driven than the continuous-style endurance you’d get from sports like distance running/cycling—so the alignment is medium rather than high.	[21] [23]
Build strength and power	high	This is one of the tight five’s core job descriptions: mass + force for scrums, set-piece pushing/traction, and repeated collisions close to the ground. That naturally rewards strength development and functional power (especially for driving and bracing) and usually leads to substantial improvements if you train consistently.	[21] [24]
Challenge myself	high	This role is physically and mentally demanding: close-contact collisions, repeat scrummaging under load, and needing to stay technically correct while fatigued. For most amateurs, that feels like a true challenge with real progress milestones.	[21] [25]
Compete and measure myself	medium	Rugby has match competition and season standings, but tight-five performance is harder for amateurs to “self-measure” than for roles with obvious stats (like try-scoring). Still, you can track impact (scrum effectiveness, penalties avoided, carries/turnovers, defensive work rate) with coach feedback and team stats—so medium alignment.	[21] [26]
Improve agility and coordination	low	There is coordination required (binding, timing, body angles, and maintaining technique under pressure), but compared with positions that constantly sprint, evade, and change direction, tight five agility/coordination gains are less “rewarded” by the role’s primary scoring/pacing features. You’ll still improve coordination a bit, but it’s not the best alignment to agility goals.	[21] [27]
Improve balance and control	medium	Scrummaging and repeated collisions require excellent bracing and postural control (staying stable while forces push you around). That gives meaningful balance improvements. However, the balance challenge is very context-specific (scrum/contact), so it’s not as broadly “balance training” as sports that focus on standing stability (gymnastics/yoga).	[21] [25]
Improve flexibility and mobility	low	Tight five training is dominated by collisions, scrums, and strength work. Mobility and range of motion can improve somewhat (through getting into low positions repeatedly), but it’s usually not the main driver, so dedicated flexibility/mobility would still be needed for meaningful gains.	[21] [23]
Improve general health and fitness	high	The tight five are active for long periods of a match: they drive in scrums, contest set-pieces, carry the ball, and constantly get into collision/close-contact work. That gives a lot of whole-body conditioning (strength endurance + some aerobic/anaerobic fitness), which makes it a strong fit for general health and fitness at the amateur level.	[21] [28] [29]
Improve speed and explosiveness	low	Tight five are explosive in short “push/drive” moments and in body-positioning for scrums, but top-end speed and repeated open-field acceleration are usually less central than for outside backs/wing-type roles. So you may gain some explosiveness, but it’s not the primary, best-matched outcome.	[21] [30]
Learn new skills and master technique	high	Tight five is very technique-based: scrum engagement, binding, body positioning, set-piece timing, and close-contact mechanics. Even at an amateur level, coaching quality and reps matter a lot, and improvements are noticeable over time—so mastery is a strong alignment.	[21] [31]
Lose weight	low	Tight five players are often very powerful/large-body athletes, and while they do lots of physical work, their training is more oriented toward strength, collisions, and set-piece contests than toward steady calorie-burning cardio. Weight loss can happen, but it’s less reliably “served” by this role than for speed-based positions (and injuries can also interrupt training).	[21] [22]
Make friends and feel a sense of belonging	high	Rugby union is strongly club-based and social. The tight five often form close bonds through shared set-piece work and repeated match/tackle/scrum experiences with the same unit and teammates. That makes this a strong fit for belonging.	[22]
Reduce stress and feel better	medium	Being part of a team and getting vigorous exercise often improves mood and reduces stress. But because tight five roles are contact-heavy and involve injury concerns (scrums/tackles), some players feel more physically and mentally “strained,” making the net stress benefit medium rather than high.	[22] [25]
Spend time with people I care about	low	You’ll absolutely see teammates you care about, but the activity itself is intense and contact-heavy—so it’s not well matched to the specific idea of “chatting and catching up while practicing.” Conversation is usually limited to before/after training.	[26]

Preferences

Factor	Alignment	Reasoning	Sources
Competition-focused environment	high	Rugby union is organized around leagues and matches where forward dominance in scrums/mauls and overall team results translate to standings. Tight five impact is directly evaluated in competitive play.	[32]
Enjoys contact	high	This is one of the most contact-heavy sets of roles in rugby: tight five are expected to thrive in close, physical confrontations that often involve collisions and scrummaging under load.	[33] [34]
Flexible Time Table	low	Tight five participation usually requires synchronized team training (scrum technique, set-piece rehearsals) and match-day availability. While you can do individual strength conditioning anytime, the role’s core development depends on scheduled team sessions.	[32]
Indoor setting	none	Rugby union tight five responsibilities are built around outdoor field set-pieces (scrums/mauls) with full contact. Indoor gyms may be used for training, but the sport/role itself is not typically “an indoor setting” sport.	[32]
Long steady efforts	none	Tight five does need aerobic fitness, but the defining demands are intermittent collisions, scrum/maul drives, and repeated high-force efforts—not long steady pacing.	[35] [36]
Low impact on joints	none	Tight five roles are mass/force-driven and involve scrums and repeated collisions, which generally increase joint/soft-tissue loading compared with non-contact or low-collision sports. Even with safer technique, the impact profile is not “low impact.”	[33] [34]
Mostly individual	low	Yes, tight five players generate a lot of personal force and repeat physical tasks, but in amateur play your outcome is mostly determined by how your unit performs together (set-piece stability, coordinated drive, and synchronized technique) rather than isolated “one person” performance.	[37] [38]
Non-contact	none	Tight five is explicitly close-contact: scrums, repeated collisions, and forceful forward play. Even if some technical aspects reduce injury risk, direct contact is central to the role.	[33] [39]
Outdoor setting	high	Scrums, mauls, and open-contact forward phases are designed for a pitch and are strongly tied to outdoor match conditions and the real geometry of the field.	[37] [40]
Playful recreational atmosphere	low	Even at amateur level, tight five is among the most physically punishing roles due to mass/force confrontations and repeated collisions. That tends to make the culture more serious and performance-oriented than “light and playful.”	[33] [34]
Routine and structure	high	Tight five roles are unusually structured: scrums have set rules, lineout mechanics exist (even if you’re not the jumper), and forwards have repeated phase responsibilities. Practice is built around repeatable set-piece patterns even though match details vary.	[37] [40]
Short explosive efforts	high	Scrums and close-contact phases are short, forceful bursts—drive phases and collisions are dominated by maximal or near-max force efforts rather than steady, moderate output.	[37] [41]
Tactical and strategic	medium	There is strategy (scrum tactics, when/how to apply pressure, how the forward pack sequences carries/defense), but compared with halfbacks/backs, tight five often lives more in execution: win the set-piece, drive through contact, secure stability. So strategy exists, but it’s not the primary “mind game” skill for this position group.	[37] [38]
Team environment	high	Tight five (front row/locks) are fundamentally a set-piece engine for the whole team. Your effectiveness in scrums and mauls depends on coordinated teammates (timing, binding/technique, pressure, and team shape), so it’s not a solo-style role even if you do a lot of individual physical work.	[37] [38]
Technique-heavy	high	Tight five relies on specialized technique: scrum engagement, binding/hand position, body angle/lever mechanics, and safe collision technique. Physical strength matters, but it only converts to results when executed with correct technical form.	[37] [38] [39]
Variety and novelty	medium	You repeat core tasks (scrum engagements, close-contact carries, ruck/physical contests), so it can feel repetitive from play to play. Novelty comes from opponents’ styles and how breakdowns/field positions evolve, but the core “job” remains fairly consistent.	[38] [40]
Water environment	none	No meaningful water component for rugby union tight five roles.	—

Injuries

Risk

Factor	Value	Definition	Full reasoning	Sources
Achilles tendon pain (tendinopathy)	low	Pain and irritation in the Achilles tendon at the back of the ankle.	Rugby union produces a meaningful overall lower-limb injury burden, so Achilles tendinopathy is plausible. However, tighter evidence/examples for tight five specifically more consistently point to head/neck/spine and shoulder, and to other lower-limb strains/sprains. That makes Achilles tendinopathy risk low rather than medium/high.	[42]
ACL injury	low	A major ligament injury inside the knee, often linked to pivoting, landing, or sudden deceleration.	Tight five do experience knee loading in collisions and contact phases, but ACL is generally not the dominant “headline” category compared with knee ligament/joint injuries broadly. With limited tight-five-specific ACL elevation evidence from the sources used here, risk is low.	[42]
Ankle sprain	medium	A stretched or torn ankle ligament, usually after the foot rolls awkwardly.	Rugby union time-loss injury epidemiology shows ankle injuries are a meaningful lower-limb category. Tight five involvement in scrums and collisions can also lead to awkward foot placements and contact-related twisting, so ankle sprain risk is medium.	[42]
Calf strain	low	A pulled or overloaded calf muscle, often felt during pushing off, sprinting, or jumping.	Calf strain risk exists in rugby, but compared with groin/hip, shoulder, neck/spine, and general lower-limb injuries, tight five-specific calf-strain risk is less strongly supported. So low.	—
Finger or hand impact injury	low	Pain from jamming, bending, or striking the fingers or hand during sport.	Upper limb injuries occur in rugby, but for tight five the highest-burden risks in the evidence are generally other regions. So finger/hand impact risk is low rather than medium/high.	[45]
General forearm overuse pain	none	Ongoing forearm pain from repeated gripping, lifting, or arm use when the exact tendon is unclear.	Rugby union injury data tends to highlight head/neck, shoulder, and lower-limb muscle/tendon/sprain clusters for contact roles. Forearm overuse pain (as a specific diagnosis) is not a typical standout risk category for tight five compared with those higher-burden regions, so the default is none.	—
General foot or ankle pain	low	Ongoing foot or ankle pain when the exact structure or diagnosis is unclear.	Lower-limb pain can occur across rugby roles, but the mapping requires diagnosis-specific support. Since the strongest rugby surveillance emphasis tends to be on knee/ankle ligament/joint injuries and other major regions, general foot/ankle pain risk is low.	[42]
General hip or groin pain	high	Ongoing hip or groin pain when the exact structure or diagnosis is unclear.	Rugby injury surveillance commonly identifies hip/groin as a frequent injury region. Tight five have particularly high physical collisions and powerful lower-body driving, which aligns strongly with groin/hip pain mechanisms. So risk is high.	[46]
General knee pain	medium	Ongoing knee pain when the exact structure or diagnosis is unclear.	Rugby union time-loss injury epidemiology highlights knee injuries as a major category overall. Tight five’s close-contact role increases exposure to these knee loading mechanisms, supporting medium risk for general knee pain.	[42]
General lower-back pain	high	Ongoing lower-back pain when the exact source is unclear.	Spinal injury risk in rugby is well described, and tight five participate in scrummaging and tackle/weight-bearing forces. That combination supports high risk for general lower back pain in this role mapping.	[48]
General lower-leg pain	low	Ongoing shin or calf pain when the exact diagnosis is unclear.	Rugby has a meaningful lower-limb injury burden, so plausibility exists. But because this is a broad pain category and tight-five exposures often translate more into hip/groin, knee, and contact-related issues, risk is low.	[42]
General shoulder pain	high	Ongoing shoulder pain when the exact structure or diagnosis is unclear.	Shoulder injury burden in rugby is well documented, and tight five add intense set-piece contact exposure. Therefore shoulder pain risk is high for this role mapping.	[42] [49]
General wrist or hand pain	none	Ongoing wrist or hand pain when the exact structure or diagnosis is unclear.	Because diagnosis specificity is limited and tight five injury emphasis is more strongly on neck/spine/shoulder and lower-limb, risk is none.	—
Golfer's elbow	none	Pain on the inside of the elbow linked to overload in the forearm tendons.	While props may do gripping/hand contact, rugby injury surveillance emphasizes other injury regions for front-row players. With no strong role-specific signal for medial epicondylitis, risk is none.	—
Groin strain	high	A pulled or irritated groin muscle, often felt in cutting, sprinting, or kicking movements.	Hip/groin is a repeatedly common rugby injury region, and tight five’s role includes forceful, repetitive hip actions and collision-driven loading—matching common groin strain mechanisms. That supports high risk.	[46]
Hip flexor strain	medium	A strain or overload in the front-of-hip muscles that help lift the leg.	Because hip/groin is common in rugby, hip flexor strain can occur. However, the evidence basis here is stronger for the broader hip/groin region than for hip-flexor-strain specifically as the dominant tight-five diagnosis, so risk is medium.	[46]
Side-of-hip tendon pain	low	Irritation of the hip or gluteal tendons around the outer side of the hip.	Mechanically, loose/prop-like roles can load glute tendons during acceleration, driving, and stabilization. But diagnosis-level linkage to tight five tends to be weaker than for broader hip/groin pain and other muscle strain patterns, so risk is low.	[42]
Lower-back disc irritation	medium	Lower-back pain that may involve irritation of a spinal disc and sometimes pain spreading into the leg.	Because rugby exposes players to spinal injuries and lumbar loading mechanisms, disc irritation is plausible. However, the diagnosis label is specific, and role-specific incidence is less clear than for general low back pain, so risk is medium.	[48]
Mechanical lower-back pain	high	Common lower-back pain related to movement, loading, stiffness, or irritated supporting tissues.	This category aligns well with the mechanical loading exposure tight five experience. Rugby spinal injury exposure and scrummaging/tackle mechanisms support high risk for mechanical low-back pain in this role mapping.	[48]
Meniscus injury	low	Irritation or tearing of the knee cartilage that helps cushion and stabilize the joint.	Meniscus injuries are possible in rugby due to collisions and knee loading, but diagnosis-specific tight-five incidence for meniscus isn’t strongly established in the sources consulted. With limited diagnostic specificity, risk is low.	[42]
Jumper's knee (patellar tendinopathy)	none	Pain and irritation in the tendon just below the kneecap.	Tight five experience significant lower-body loading, but without a clear diagnostic signal that patellar tendinopathy is a common tight-five outcome, risk remains none.	—
Front-of-knee pain (patellofemoral pain)	low	Pain around or behind the kneecap that often flares with repetitive knee bending.	Since knee pain is plausible but patellofemoral pain isn’t specifically established as a top tight-five outcome, risk is low.	[42]
Heel pain (plantar fasciitis)	none	Irritation of the tissue under the foot that often causes pain near the heel.	While plantar fascia can be stressed in runners, assigning risk requires stronger evidence that this specific diagnosis is a typical rugby outcome for tight five. With no clear role-specific signal, the default is none.	—
Rotator cuff irritation	medium	Pain and overload in the shoulder muscles and tendons that help control arm movement.	Given high shoulder exposure, rotator-cuff irritation is plausible. However, diagnosis-specific frequency data is less clear than for general shoulder pain, so risk is medium.	[42]
Shin splints	none	Exercise-related pain along the shin that often appears when impact load rises too quickly.	Without clear evidence of shin splints being a common tight-five injury diagnosis, risk stays none.	—
Shoulder impingement-type pain	medium	Shoulder pain that appears when tissues feel pinched or irritated during arm elevation.	Because shoulder injury burden is real and impingement is a plausible mechanism, risk is medium. Specific incidence for impingement syndrome in tight five is not strongly established in the sources used, preventing a high rating.	[42]
Shoulder instability or dislocation	medium	A shoulder that has slipped out, partly slipped out, or feels unreliable in vulnerable positions.	Rugby shoulder trauma exposure makes instability/dislocation plausible. However, it’s typically a lower-frequency event than general shoulder problems, so medium risk is appropriate.	[42]
Back stress reaction (spondylolysis)	none	A stress injury in the back often linked to repeated extension and rotation loading.	Without strong evidence that tight five rugby creates enough repetitive lumbar extension to drive spondylolysis, and given this is a specific diagnosis, risk remains none.	—
Tennis elbow	none	Pain on the outside of the elbow linked to overload in the wrist and forearm tendons.	Given the dominant tight-five exposure is set-piece collision and lower-body/shoulder/contact forces, tennis elbow is not clearly elevated as a typical risk for this role category—so risk remains none.	—
Shin bone stress injury	none	Stress irritation in the tibia from repeated impact that has outpaced recovery.	Given the diagnosis specificity and lack of tight-five stress-injury emphasis in the consulted rugby epidemiology sources, risk is none.	—
Wrist sprain	none	A stretched or irritated wrist ligament, often after a fall, impact, or awkward bend.	Given lack of strong evidence, default risk remains none.	—
Wrist tendon pain	none	Irritation of wrist tendons from repeated gripping, racquet use, lifting, or supporting body weight.	Even though hand/grip demands exist, the mapping requires stronger support for wrist tendinopathy being a common tight-five outcome. With insufficient signal, risk is none.	—

Prevention

Factor	Value	Definition	Full reasoning	Sources
Achilles tendon pain (tendinopathy)	low	Pain and irritation in the Achilles tendon at the back of the ankle.	Tendinopathy prevention depends on progressive, well-dosed loading; rugby provides loading but not in a symptom-guided, tendon-programmed way. So prevention is only low.	[43]
ACL injury	none	A major ligament injury inside the knee, often linked to pivoting, landing, or sudden deceleration.	Because we’re not assuming extra targeted ACL-prevention training beyond normal rugby, there’s no confident basis to claim a net preventive effect from rugby participation alone.	—
Ankle sprain	low	A stretched or torn ankle ligament, usually after the foot rolls awkwardly.	Because we cannot assume additional proprioception/balance training beyond normal play, the preventive attribution from rugby itself is limited. So prevention is low.	[44]
Calf strain	none	A pulled or overloaded calf muscle, often felt during pushing off, sprinting, or jumping.	Calf strain prevention depends on progressive calf loading and managing fatigue; rugby alone doesn’t guarantee that net benefit for calf strains in this mapping.	—
Finger or hand impact injury	none	Pain from jamming, bending, or striking the fingers or hand during sport.	No confident evidence supports that playing rugby alone prevents finger/hand impact injuries; hence prevention is none.	—
General forearm overuse pain	none	Ongoing forearm pain from repeated gripping, lifting, or arm use when the exact tendon is unclear.	Because we’re not assuming extra, condition-specific forearm loading beyond normal play, there’s no clear preventive mechanism to credit from rugby itself for forearm overuse pain.	—
General foot or ankle pain	none	Ongoing foot or ankle pain when the exact structure or diagnosis is unclear.	Because foot/ankle pain causes are varied, and we’re not assuming extra management strategies beyond normal rugby, prevention can’t be confidently assigned.	—
General hip or groin pain	low	Ongoing hip or groin pain when the exact structure or diagnosis is unclear.	Without assuming targeted adductor/hip rehab outside normal play, rugby’s net prevention effect is modest. Therefore low prevention is assigned.	[47]
General knee pain	none	Ongoing knee pain when the exact structure or diagnosis is unclear.	Without assuming additional targeted knee/landing-mechanics programs outside normal play, no net prevention effect can be confidently assigned.	—
General lower-back pain	none	Ongoing lower-back pain when the exact source is unclear.	Without assuming targeted spine-prevention training beyond normal rugby, we cannot credit rugby as a reliable preventive strategy. Contact exposure can continue to provoke symptoms, so prevention is none.	—
General lower-leg pain	none	Ongoing shin or calf pain when the exact diagnosis is unclear.	No confident net preventive effect can be attributed to rugby alone for generic lower-leg pain.	—
General shoulder pain	none	Ongoing shoulder pain when the exact structure or diagnosis is unclear.	Without assuming extra, targeted shoulder stability/technique programs beyond normal training, rugby itself cannot be credited as a reliable preventive intervention for shoulder pain. Therefore none.	—
General wrist or hand pain	none	Ongoing wrist or hand pain when the exact structure or diagnosis is unclear.	Without assuming targeted hand/wrist tendon strengthening and load management beyond normal rugby, no preventive effect is credited; prevention is none.	—
Golfer's elbow	none	Pain on the inside of the elbow linked to overload in the forearm tendons.	No confident evidence supports a net protective effect for this specific tendon pain diagnosis from rugby participation alone.	—
Groin strain	low	A pulled or irritated groin muscle, often felt in cutting, sprinting, or kicking movements.	Because we can’t assume extra adductor-focused prevention programs beyond normal training, the preventive effect from rugby participation alone is limited (low).	[47]
Hip flexor strain	low	A strain or overload in the front-of-hip muscles that help lift the leg.	Without additional, symptom-guided hip-flexor conditioning outside normal play, the prevention effect is modest—low.	—
Side-of-hip tendon pain	low	Irritation of the hip or gluteal tendons around the outer side of the hip.	Because tendon rehab principles emphasize progressive loading, rugby provides some adaptive stimulus. But rugby is not a dedicated tendon-conditioning prevention program, so prevention is low.	[43]
Lower-back disc irritation	none	Lower-back pain that may involve irritation of a spinal disc and sometimes pain spreading into the leg.	We’re not assuming extra targeted prevention programs beyond standard rugby. Given ongoing spinal loading, the net preventive effect cannot be credited.	—
Mechanical lower-back pain	none	Common lower-back pain related to movement, loading, stiffness, or irritated supporting tissues.	Without assuming additional targeted core/mobility and load-management programs, rugby itself is not a dependable preventive strategy. Prevention is none.	—
Meniscus injury	none	Irritation or tearing of the knee cartilage that helps cushion and stabilize the joint.	Because we cannot assume additional targeted prevention programs, and rugby includes twisting/impact exposures, prevention is none.	—
Jumper's knee (patellar tendinopathy)	none	Pain and irritation in the tendon just below the kneecap.	Prevention requires progressive tendon loading and load management; rugby alone doesn’t guarantee that net preventive effect for this specific condition.	—
Front-of-knee pain (patellofemoral pain)	none	Pain around or behind the kneecap that often flares with repetitive knee bending.	No strong evidence supports a net prevention effect from rugby participation alone without targeted strengthening/mechanics work.	—
Heel pain (plantar fasciitis)	none	Irritation of the tissue under the foot that often causes pain near the heel.	Plantar fasciitis prevention depends on factors like load management and foot mechanics; rugby exposure can both condition and irritate the tissue, so no net preventive effect is credited.	—
Rotator cuff irritation	none	Pain and overload in the shoulder muscles and tendons that help control arm movement.	Rotator cuff irritation prevention often depends on targeted strengthening, mechanics, and sometimes load modification. Without assuming that beyond rugby, prevention is none.	—
Shin splints	none	Exercise-related pain along the shin that often appears when impact load rises too quickly.	Shin splints prevention is usually tied to load management and progressive conditioning; rugby alone doesn’t guarantee net prevention, so none.	—
Shoulder impingement-type pain	none	Shoulder pain that appears when tissues feel pinched or irritated during arm elevation.	No confident net preventive effect from rugby participation alone for this specific shoulder syndrome; prevention is none.	—
Shoulder instability or dislocation	none	A shoulder that has slipped out, partly slipped out, or feels unreliable in vulnerable positions.	Without assuming targeted stability training beyond normal play, no reliable preventive effect can be assigned. Prevention is none.	—
Back stress reaction (spondylolysis)	none	A stress injury in the back often linked to repeated extension and rotation loading.	Prevention would depend on extension-load management and targeted conditioning; rugby participation alone doesn’t guarantee net prevention.	—
Tennis elbow	none	Pain on the outside of the elbow linked to overload in the wrist and forearm tendons.	Without assuming extra targeted rehab/strengthening beyond normal play, there’s no solid basis to assign prevention for tennis elbow.	—
Shin bone stress injury	none	Stress irritation in the tibia from repeated impact that has outpaced recovery.	Prevention is mainly workload/conditioning management; rugby participation alone doesn’t guarantee that net effect.	—
Wrist sprain	none	A stretched or irritated wrist ligament, often after a fall, impact, or awkward bend.	No confident net preventive effect for this specific diagnosis from sport participation alone; prevention is none.	—
Wrist tendon pain	none	Irritation of wrist tendons from repeated gripping, racquet use, lifting, or supporting body weight.	Tendinopathy prevention requires progressive tendon loading and symptom management; rugby alone doesn’t guarantee that net effect for wrist tendinopathy. Prevention is none.	—

Heal

Factor	Value	Definition	Full reasoning	Sources
Achilles tendon pain (tendinopathy)	none	Pain and irritation in the Achilles tendon at the back of the ankle.	Achilles tendinopathy recovery depends on symptom-guided load progression; normal tight-five training doesn’t guarantee the correct dosing or necessary temporary unloading of aggravating actions. Therefore healing is none.	[43]
ACL injury	none	A major ligament injury inside the knee, often linked to pivoting, landing, or sudden deceleration.	ACL recovery depends on medical/surgical decisions and structured rehabilitation. Continuing rugby is not a healing intervention, so healing is none.	—
Ankle sprain	none	A stretched or torn ankle ligament, usually after the foot rolls awkwardly.	Ankle sprain recovery needs symptom-guided return-to-play and load control. Tight five play can also re-expose the injured ankle repeatedly, so no reliable healing benefit is credited.	—
Calf strain	none	A pulled or overloaded calf muscle, often felt during pushing off, sprinting, or jumping.	Calf strain recovery depends on staged return and symptom-guided loading; rugby play can re-injure, so healing is none.	—
Finger or hand impact injury	none	Pain from jamming, bending, or striking the fingers or hand during sport.	Hand/finger recovery depends on protection, reduced re-injury, and local management; rugby contact can re-injure, so healing is none.	—
General forearm overuse pain	none	Ongoing forearm pain from repeated gripping, lifting, or arm use when the exact tendon is unclear.	Overuse tendon/muscle pain typically improves with symptom-guided load management and progressive local rehab; normal tight-five play doesn’t guarantee that dosing, so no healing benefit is assigned.	—
General foot or ankle pain	none	Ongoing foot or ankle pain when the exact structure or diagnosis is unclear.	Recovery from many foot/ankle pain causes requires symptom-guided load reduction and sometimes targeted local interventions. Rugby participation alone doesn’t guarantee those conditions, so healing is none.	—
General hip or groin pain	none	Ongoing hip or groin pain when the exact structure or diagnosis is unclear.	Groin/hip recovery depends on symptom-guided load reduction and graded return. Tight five match demands can quickly re-load the area, so healing benefit is none.	—
General knee pain	none	Ongoing knee pain when the exact structure or diagnosis is unclear.	Knee pain recovery depends on symptom-guided load reduction and sometimes targeted rehab. Tight five match demands can aggravate, so healing is none.	—
General lower-back pain	none	Ongoing lower-back pain when the exact source is unclear.	Low-back pain recovery depends on graded activity and symptom-guided modification. Tight five match duties re-load the spine frequently, so healing is none.	—
General lower-leg pain	none	Ongoing shin or calf pain when the exact diagnosis is unclear.	Recovery requires symptom-guided load modification; rugby alone doesn’t ensure that, so healing is none.	—
General shoulder pain	none	Ongoing shoulder pain when the exact structure or diagnosis is unclear.	Shoulder pain recovery typically needs symptom-guided load modification and rehab; tight-five match demands can keep provoking symptoms, so healing is none.	—
General wrist or hand pain	none	Ongoing wrist or hand pain when the exact structure or diagnosis is unclear.	Wrist/hand pain recovery depends on symptom-guided loading and protection; rugby contact and scrummaging can aggravate. Healing is none.	—
Golfer's elbow	none	Pain on the inside of the elbow linked to overload in the forearm tendons.	Healing depends on symptom-guided tendon loading and sometimes load modification; continuing scrummaging/tackling can also aggravate symptoms, so healing benefit is none.	—
Groin strain	none	A pulled or irritated groin muscle, often felt in cutting, sprinting, or kicking movements.	Groin strain healing depends on symptom-guided loading progression and sometimes reduced contact/running. Tight five demands can aggravate the tissue, so healing is none.	—
Hip flexor strain	none	A strain or overload in the front-of-hip muscles that help lift the leg.	Recovery requires graded return and avoiding aggravating loads. Tight five play can re-load hip flexors frequently, so healing benefit is none.	—
Side-of-hip tendon pain	none	Irritation of the hip or gluteal tendons around the outer side of the hip.	Tendinopathy healing depends on careful symptom-guided loading progression and sometimes temporary activity modification. Tight five match demands may aggravate symptoms, so healing is none.	[43]
Lower-back disc irritation	none	Lower-back pain that may involve irritation of a spinal disc and sometimes pain spreading into the leg.	Disc irritation recovery depends on careful activity modification and sometimes targeted rehab. Rugby participation alone doesn’t ensure the right dosing, so healing is none.	—
Mechanical lower-back pain	none	Common lower-back pain related to movement, loading, stiffness, or irritated supporting tissues.	Mechanical back pain often needs symptom-guided load modification; tight five training/matches can undermine that, so healing is none.	—
Meniscus injury	none	Irritation or tearing of the knee cartilage that helps cushion and stabilize the joint.	Recovery depends on tear type/severity and structured rehab or clinical management; rugby alone isn’t a healing intervention, so healing is none.	—
Jumper's knee (patellar tendinopathy)	none	Pain and irritation in the tendon just below the kneecap.	Tendinopathy recovery depends on symptom-guided rehab dosing; rugby play can aggravate symptoms, so healing is none.	—
Front-of-knee pain (patellofemoral pain)	none	Pain around or behind the kneecap that often flares with repetitive knee bending.	Patellofemoral pain rehab is load- and symptom-sensitive; rugby alone doesn’t guarantee appropriate modification, so healing is none.	—
Heel pain (plantar fasciitis)	none	Irritation of the tissue under the foot that often causes pain near the heel.	Plantar fasciitis typically needs symptom-guided activity modification and local loading/mechanical treatment. Rugby alone doesn’t guarantee that, so healing is none.	—
Rotator cuff irritation	none	Pain and overload in the shoulder muscles and tendons that help control arm movement.	Recovery typically depends on symptom-guided activity and rehab dosing. Contact/bracing in rugby can aggravate, so healing is none.	—
Shin splints	none	Exercise-related pain along the shin that often appears when impact load rises too quickly.	Shin splints often require reduced impact/loading and symptom-guided return; rugby play can worsen, so healing is none.	—
Shoulder impingement-type pain	none	Shoulder pain that appears when tissues feel pinched or irritated during arm elevation.	Impingement recovery needs symptom-guided modification and rehab, which rugby alone does not guarantee—so healing is none.	—
Shoulder instability or dislocation	none	A shoulder that has slipped out, partly slipped out, or feels unreliable in vulnerable positions.	Because appropriate recovery depends on specialist assessment and structured rehab (and sometimes surgery), healing benefit from continued rugby alone is not credited. Therefore none.	—
Back stress reaction (spondylolysis)	none	A stress injury in the back often linked to repeated extension and rotation loading.	Because healing requires modifying provoking loads and often supervised rehab, continued rugby is not a reliable healing intervention, so healing is none.	—
Tennis elbow	none	Pain on the outside of the elbow linked to overload in the wrist and forearm tendons.	Tendon recovery relies on controlled loading and symptom management; normal play doesn’t guarantee appropriate dosing, so healing is none.	—
Shin bone stress injury	none	Stress irritation in the tibia from repeated impact that has outpaced recovery.	Because healing requires avoiding provoking loading and often supervised rehab, continued rugby is not credited with healing benefit; none.	—
Wrist sprain	none	A stretched or irritated wrist ligament, often after a fall, impact, or awkward bend.	Sprain healing needs protection and symptom-guided return; continued contact can re-injure, so healing is none.	—
Wrist tendon pain	none	Irritation of wrist tendons from repeated gripping, racquet use, lifting, or supporting body weight.	Tendinopathy healing depends on symptom-guided loading progression and often load reduction from provoking activities. Rugby contact/scrummaging can aggravate, so healing is none.	—

Past-sport transfer logic

Past sport	Average correlation (success)	Std dev	Correlation reasoning	Correlation sources
american-football-defensive-back	0.22	0.14	Defensive back success should show a modest positive correlation with rugby union tight five success because both environments reward collision tolerance, bracing technique, balance under contact, and the ability to keep functioning amid physical pressure. However, tight five roles are heavily constrained by rugby-specific set-piece skills (scrum mechanics, pushing/leverage coordination, stability in controlled collisions) and different movement/force application patterns than open-field coverage. These specificity gaps keep the correlation from becoming high. Net expectation: a modest positive correlation with considerable between-athlete variability driven by how quickly they learn scrum/set-piece mechanics and the extent of prior rugby experience.	[50] [51] [52] [53]
american-football-line-player	0.55	0.18	American football line player and rugby union tight five share substantial overlap in the “close-contact collision engine”: generating force in short bursts, pad/shoulder contact skills (leveraging body position), and the ability to operate effectively in traffic while maintaining stability. However, tight five performance depends on rugby-specific set-piece mechanics—scrum engagement angles, binding technique, coordinated timing with teammates, and lineout/ruck entry habits (depending on role)—which aren’t taught in the same way for American football linemen. That mismatch prevents the correlation from being extremely high and increases variability. Thus the correlation should be clearly positive and moderately strong (more than for open-field roles), with a moderate-to-large standard deviation reflecting that some football linemen transition well into rugby set-piece roles, while others struggle with scrum law/technique and the coordinated body positions required.	[54] [55]
american-football-linebacker-tight-end	0.5	0.16	Linebacker/tight end success should correlate moderately-to-strongly with rugby union tight five success because both are high-contact forward roles that reward: mass + leverage, repeated forceful engagements, body positioning, and the ability to operate effectively in tight, crowded spaces while absorbing contact. However, the tight five has major determinants that are rugby-specific: scrum/maul mechanics, set-piece stability, binding/footwork patterns, and timing/positioning governed by rugby laws. Football LB/TE training emphasizes tackling/blocking leverage in open-play traffic (and for TE, pass/run roles) rather than the specialized set-piece technique that largely differentiates tight five performance. So carryover remains positive and relatively strong for general contact/strength/body-control skills, but capped because rugby tight five technique and set-piece mechanics dominate many outcomes.	[56] [57] [58]
american-football-quarterback	0.2	0.12	Quarterback success should have a modest positive correlation with rugby tight five success because there is some transferable “football IQ” and positioning/phase understanding in a contact sport: recognizing shapes, anticipating where the ball will be, and maintaining decision quality while under pressure. However, the correlation cannot be large. Tight five performance is dominated by event- and role-specific mechanics: scrummaging stability and body angles, set-piece technical execution, repeated collision/entry and breakdown involvement, and close-contact coordination with teammates. Those motor patterns and rule-specific techniques are largely absent from quarterback training, which is instead centered on throwing mechanics and offensive play direction. The big technical mismatch creates substantial variance, so the carry-over remains low-to-moderate.	[59] [60]
american-football-receiver-running-back	0.1	0.08	Receiver/running back performance should correlate only weakly with rugby union tight five success. There is some overlap in general collision readiness: (1) handling contact/balance while moving, and (2) aggressive short bursts that can occur in close contests. However, tight five outcomes depend heavily on rugby-specific set-piece and close-contact technical skills: scrum mechanics (binding, engagement posture, coordinated pushing), ruck/maul positioning and body angles under rugby law constraints, and role-specific decision loops for maintaining stability and leverage. WR/RB roles emphasize open-field acceleration, route timing, and receiving/running mechanics rather than the constrained force-production and posture control required in scrums and other tight-five duties. That mismatch keeps the carry-over near the low end. A plausible average correlation is therefore ~0.10 with moderate uncertainty.	[61]
athletics-distance	0.12	0.08	Distance running success should have a small positive correlation with rugby union tight-five success because endurance and training discipline help with match involvement and fatigue resistance. However, tight five roles depend strongly on scrum/lineout set-piece stability, maximal force production, and sport-specific collision/engagement mechanics that distance running does not develop. Therefore the overall correlation is positive but low and variable, with many distance athletes needing substantial strength-and-set-piece development to perform well.	[62] [63] [64]
athletics-jumps-high-jump	0.12	0.09	High-jump performance should correlate only weakly with tight five success. There is some shared, technique-adjacent athletic component: explosive leg/hip power, balance, and elastic body control that can help with short bursts and maintaining body position during contact. However, tight five performance is dominated by rugby-specific set-piece and contact technique—scrummaging mechanics, leverage and binding, repeated collision bracing patterns, and set-piece positional execution under sustained strain. Those are largely absent from high-jump training. In addition, the kinetic chain emphasis differs: high jump is vertical impulse/landing, while tight five requires sustained or repeated pushing/engagement in different directions and often includes more isometric drive patterns. Therefore the expected correlation remains small and highly variable.	[65] [66] [67]
athletics-jumps-long-triple-jump	0.08	0.08	Long jump/triple jump proficiency reflects explosive lower-body power, elastic stiffness/recoil, and coordinated force production that can provide a small athletic advantage for tight five close-contact demands (e.g., scrum-drive bursts and repeated force generation). However, tight five success is dominated by rugby-specific technique: scrum body positions, binding/leverage mechanics, set-piece timing, collision/contact skills, and repeated ruck/maul execution. Those are largely non-overlapping with jumping-event technique. Therefore the expected carry-over is small but slightly positive, with substantial individual variability.	[68] [69] [70]
athletics-jumps-pole-vault	0.1	0.08	Pole vault success should have only a small-to-modest positive correlation with rugby union tight five success. Shared qualities include general explosive whole-body force production, balance/body control, and ability to recover stability after impact—helpful for scrum and close-contact work. However, tight-five excellence is heavily determined by rugby-specific set-piece mechanics (scrum engagement technique, leverage, hand placement, body positioning), contact skills, and tactical discipline. Pole vault’s unique motor programs (approach/takeoff/inversion/landing constraints) do not directly train those. Net expected carryover is low (roughly ~0.05–0.18), centered around ~0.10 with moderate variance.	[71] [72] [73]
athletics-middle-distance	0.08	0.07	Middle-distance performance should have only a weak relationship with future rugby tight five success. There is limited overlap via general conditioning, running economy, and repeat-effort capacity that help with match demands and recovery. However, tight five outcomes are dominated by rugby-specific contact and set-piece skills (scrum/lineout technique, body positioning/leverage, collision mechanics, ruck stability) and strength/power expression. Those have minimal technical carryover from pacing/aerobic middle-distance running, so the correlation stays low.	[74] [75]
athletics-sprints-hurdles	0.1	0.12	Sprints and hurdles should only correlate weakly with tight five because the overlap in purely technique/learning is limited. Tight five roles demand high force production in static and semi-static positions (scrum), repeat collision tolerance, and set-piece technical mastery (binding, body angles, foot placement, leverage, and coordination with teammates). While sprint/hurdle success indicates athletic power and general coordination, it doesn’t directly provide scrum/ruck/wrestling technique or the specific contact mechanics required to perform safely and effectively. There is still a small positive link: athletes with good power and stiffness can sometimes handle the explosive drives in scrums and short bursts during open play better than purely endurance-type athletes. Net: small positive correlation (~0.10) with high uncertainty depending on whether the athlete’s sprint/hurdle success translated into transferable strength/stabilization skills (learned with training) versus being mainly “track-race” mechanics.	[76]
athletics-throws-discus	0.19	0.08	Discus performance indicates rotational strength, leverage, hip–shoulder sequencing, rhythm/timing, and efficient whole-body force transfer. Tight-five (scrum and close-contact forward) roles also require strong force production, bracing and stability, and repeated collisions in which the body must transfer force effectively through the trunk and hips. That creates a meaningful positive correlation in the general athletic “force/leverage” components. However, tight-five success is strongly constrained by rugby-specific technique and perceptual-cognitive demands: set-piece scrum mechanics, binding/engagement coordination, hand/arm placement rules, timing of collisions and entries, and repeated contact management. Discus does not train those motor patterns or the sport’s decision context, limiting transfer. A realistic Bayesian estimate is therefore modest-to-moderate positive: ~0.19 average correlation with std dev ~0.08, reflecting that some discus athletes cross-train in rugby/contact sports (raising the relationship) while others do not (lowering it).	[77] [78] [79]
athletics-throws-hammer-throw	0.18	0.09	Hammer throw success indicates strong whole-body force production, efficient kinetic-chain sequencing, and the ability to maintain balance while applying large forces in a resisted rotational movement. Tight five roles also value leverage, set-piece stability, and the ability to generate and resist force under repeated collision conditions. That creates a moderate positive correlation through general “force + body control” skills. However, tight five performance is heavily determined by rugby-specific techniques: scrum mechanics (angles, foot placement, binding), repeated contact entry mechanics, and tactical set-piece/phase execution. Hammer throw’s implement-leverage throw mechanics do not directly train those. Net expected correlation is moderate but not high.	[80] [81]
athletics-throws-javelin	0.2	0.09	Javelin performance is associated with strong whole-body force production and coordinated kinetic-chain sequencing (legs → trunk → shoulder/arm) plus good timing and ability to generate power quickly. Those elements can carry over modestly to rugby union tight five roles, which value: - powerful, coordinated body action in short bursts (driving/carrying, short-range force) - upper-body/shoulder contribution for contact and close-range contests - general ability to learn and refine complex movement mechanics through repetition. However, tight five performance is heavily determined by rugby-specific close-contact technique and decision-making: scrummaging mechanics, ruck/maul entry and legality-aware body positions, collision/tackle technique across many repeated contacts, and set-piece and breakdown skills. Javelin’s dominant skill (run-up into a throwing release) has limited direct overlap with those collision and set-piece motor patterns. Therefore the carry-over should be positive but not large—around the low 0.2s on average.	[82]
athletics-throws-shot-put	0.3	0.12	Shot put success indicates strong whole-body maximal-force production, trunk bracing, leverage, and the ability to apply explosive force in coordinated bursts. Tight five rugby roles similarly require force application, collision tolerance, set-piece stability, and repeat physical contest capacity. However, tight five effectiveness is not only physical: it depends heavily on rugby-native set-piece technique and timing (scrum engagement/body positioning, binding/clearing mechanics, maul participation), plus coordination with teammates under specific rules. Shot put doesn’t train those learned interaction patterns. Therefore the carryover should be positive and moderately sized—higher than for “speed/precision” rugby roles—but capped by the rugby-specific technical and cooperative determinants. Expect noticeable scatter due to differences in role subtype and prior rugby/contact background.	[83] [84] [85] [86]
badminton	0.06	0.05	Tight five rugby roles depend heavily on rugby-specific contact and set-piece skills: scrummaging technique (binding/engagement timing, leverage, body alignment), repeated collision contact mechanics, and set-piece stability. Badminton contributes some transferable general qualities—balance, body control, and ability to learn under pressure—but it does not meaningfully train the core technical patterns needed for scrums and sustained close-contact collisions. Therefore the expected correlation between past badminton success and future tight five success should be small, near ~0.06, with moderate variance driven by differences in prior strength/contact training and rugby exposure.	[87] [88] [89] [90]
baseball-catcher	0.02	0.03	A baseball catcher’s technical success mainly reflects receiving/blocking, ball-tracking, and rapid read-and-react decision-making. Rugby union tight-five roles are dominated by scrum and close-contact mechanics: binding/engagement technique, set-piece positioning, collision repeatability, and brief high-force tasks with very specific rugby rules. There is little direct technical overlap, so predictive carry-over is near zero. Some small positive correlation remains from general coordination, athleticism, and learning speed, but the dominant determinants of tight-five performance are rugby-specific contact/set-piece skills rather than transferable catcher skills.	[91] [92] [93]
baseball-field-player	0.09	0.07	Baseball field players can transfer some useful technical ingredients to rugby tight five roles—especially general coordination, reading of play, and basic ball-handling/throwing comfort. That can slightly help with learning around set pieces and maintaining body control under pressure. However, tight five success is dominated by rugby-specific, highly technical set-piece and close-contact demands: scrum and ruck collision mechanics, binding/body position, leverage and force application within strict rules, and repeated high-load impacts. Those mechanics are largely absent in baseball fielding. Because the functional overlap is limited mostly to general athleticism and perception, the expected correlation should be small (though positive), around the ~0.09 range.	[94] [95] [96]
baseball-pitcher	0.06	0.05	Baseball pitching can correlate slightly with rugby tight five success because pitchers have general coordination and comfort with repeated high-force actions, and can have decent hand–eye coordination for handling/distributing the ball quickly. But tight five roles (prop/hooker/lock-like set-piece anchors) are dominated by rugby-specific set-piece technique and physical competition: scrum engagement timing, binding posture, leverage at very short range, repeated collision tolerance, and detailed ruck/maul involvement. Pitching does not train those contact-and-set-piece mechanics, so carry-over should be small. Therefore the expected relationship is a low positive correlation with relatively small-to-moderate variance (highest for pitchers who also train strong contact skills, wrestling/line drills, and set-piece technical learning).	[97]
basketball-big	0.11	0.09	Basketball Bigs often have good lower-body bracing, balance while moving in traffic, and experience operating in congested, physical-feeling environments (boxing out, rim defense, interior positioning). Those contribute some technique-like foundations: controlling posture under load, generating force with legs/core, and staying coordinated when bodies contact. But tight-five rugby roles depend strongly on rugby-specific contact/set-piece learning: scrum engagement body angles, binding, foot/shoulder positioning, ruck/maul legality, and repeated collision mechanics with precise coaching. Basketball does not train these engagement and set-piece patterns. Since we exclude physique/proportion effects, the remaining carryover is limited to general power/bracing/coordination, so the correlation should be low-to-moderate with large variability depending on whether the athlete’s basketball strengths included frequent physical play rather than mostly rim/rebounding timing.	[98]
basketball-guard	0.06	0.05	Basketball guards may transfer a small amount of general coordination, body control, and ball-handling/receiving ability. These can help with early learning of rugby skills and decision-making. But tight five success is dominated by scrum and close-contact set-piece technique (binds, body angles, force application timing), collision/tackle engagement mechanics, and highly repeatable mass/force stabilization tasks. Those motor patterns are very different from basketball guard play. Because the overlap is mostly general athleticism rather than rugby set-piece/contact technique, the correlation should be near zero to low—small positive at best.	[99]
basketball-wing	0.06	0.06	Basketball wing success should have only a weak positive relationship with tight five success because there is some overlap in general coordination and competitiveness, but tight five performance depends heavily on rugby-specific set-piece and close-contact mechanics (scrum engagement technique, body position/leverage, maul/lineout roles) and repeated collision skills. Those dominant determinants are largely absent from basketball wing training, so the correlation should be low with high variance.	[100] [101]
boxing	0.08	0.06	Boxing and rugby tight five share some general technique-adjacent components: learning to manage body position under pressure, staying coordinated while being hit/contested, and maintaining balance and aggression in close contact. That can make adaptation to rugby contact less intimidating and can speed learning of certain collision-related movement fundamentals. But the tight five role is strongly constrained by rugby-specific technical skills: scrum engagement/body mechanics, binding, set-piece stability, lineout work, ruck/maul involvement, and tackle/clean-ball technique within rugby’s rules. Boxing does not meaningfully train those mechanics. Therefore carry-over should be modest rather than large, around the low single-digit to ~0.1 range.	[102] [103] [104]
climbing-bouldering	0.1	0.06	Tight five rugby success is driven heavily by set-piece mechanics (scrum/lineout footwork and leverage), repeated collision tolerance, and team-based timing—along with substantial influence from mass/strength characteristics. Because we are excluding physique-proportion effects and focusing on technique/skill, some general transferable elements remain: bouldering can improve whole-body tension/bracing, proprioception, and the ability to apply force while staying coordinated in awkward, constrained positions. However, bouldering does not train the exact scrum/ruck/jam mechanics, binding/foot placement, or the specific contact timing and contact technique used in tight-five roles. Therefore the carry-over should be small. Plausible Bayesian center: r ≈ 0.10 with std dev ≈ 0.06 reflecting variability in whether athletes also have strength/ruck/field-scrummaging background alongside climbing.	[105]
climbing-lead	0.08	0.07	Lead climbing (longer roped lead) is associated with strong body control, balance, proprioception, and the ability to execute technical sequences while fatigued. Those can help with maintaining posture, coordination, and “technique discipline” through the physical demands of rugby. But tight five performance is dominated by rugby-specific, event-specific mechanics: scrum leverage and binding technique, coordinated set-piece timing, short-range collision engagement, and repeated explosive drive patterns. Lead climbing does not closely train these contact/scrum motor patterns. So the carry-over from lead-climbing success to tight five success should be small and variable, mainly reflecting general robustness/coordination rather than direct technique transfer.	[106] [107] [108] [109]
climbing-speed	0.06	0.04	Climbing speed can correlate slightly with tight five roles because both demand whole-body coordination, bracing, and the ability to exert force repeatedly. But tight-five success is heavily driven by rugby-specific set-piece technique (scrum mechanics, binding/engagement timing, body positioning) and repeated collision/contact skills that climbing speed does not train. With these large sport-specific gaps—and with physique/contact-mechanics confounds removed—the correlation should be small, close to low positive.	[110] [111] [112] [113]
cricket-all-rounder	0.05	0.05	Cricket all-rounder performance should have only a weak positive correlation with rugby tight five success. Some conditioning and competitive composure can transfer, but tight five dominance is largely determined by rugby-specific set-piece technique and repeated collision mechanics, which cricket does not train. With mass/force/contact tolerance advantages excluded, the remaining learnable overlap is minimal, giving a near-low correlation (~0.05).	[114] [115] [116] [117] [118]
cricket-batter	0.03	0.03	Cricket batter performance is driven primarily by perceptual timing (tracking a moving ball), hand–eye coordination, and stable lower-body mechanics for striking a bat. Rugby union tight five roles are dominated by rugby-specific learned skills: set-piece mechanics (scrum engagement/angles, lineout lifting/footwork), collision tolerance and body positioning for repeated contacts, rucking/mauling technique, and short-range force production while maintaining legality and body control in extreme contact. There is limited overlap: both require general balance, coordination, and the ability to execute repeatable body positions under pressure. However, cricket batting does not meaningfully train scrum/maul footwork, engagement technique, or collision mechanics. Therefore the correlation should be very small, near 0.00–0.05.	[119]
cricket-bowler	0.06	0.07	Cricket bowler → rugby tight five is expected to be only weakly positive. Direct technical transfer is low because bowling is an overarm projectile delivery skill, while tight five roles are defined by scrum set-piece body positioning, engagement/collision mechanics, and repeated close-contact stabilization. The non-zero correlation comes mostly from general factors: the ability to execute under pressure, tolerate repeated hard efforts, and learn new technical systems efficiently. Since rugby-specific determinants dominate, the ceiling is low. Thus a Bayesian point estimate around 0.06 with std dev ~0.07 is realistic.	[120] [121] [122] [123] [124]
cricket-wicketkeeper	0.06	0.06	Cricket wicketkeeper success should have only a small positive relationship with rugby union tight five success. There’s a bit of overlap in general athletic coordination and the ability to stay technically engaged during intense moments, but tight five performance is dominated by scrum/lineout set-piece technique, collision mechanics, and repeated high-force contact—none of which wicketkeeping trains. So the expected skill-only carryover is low (around ~0.06).	[125] [126] [127] [128]
cycling-mountain-bike-cross-country	0.06	0.06	Mountain bike cross-country success reflects general transferable attributes: aerobic base, ability to repeat surges, and some coordination/balance under fatigue and uneven terrain. These can help with overall conditioning and staying functional during repeated collisions. However, rugby union tight five performance is dominated by sport-specific technique: scrum mechanics (body angle, binding, foot pressure timing), close-contact engagement, hand/arm placement, and maximal short-range force production coordinated with set-piece rules. MTB cross-country does not meaningfully train these engagement and set-piece mechanics, and the key strength expression is different. So any correlation should be small and mostly indirect. A plausible Bayesian estimate is r≈0.06 with uncertainty around ±0.06.	[129]
cycling-road-climber	0.08	0.12	Road cycling as a climber emphasizes sustained power-to-weight output, aerobic capacity, disciplined pacing, and leg force application under fatigue. The rugby tight five also requires high work capacity across long matches (tackles, carries, ruck involvement) and the ability to repeat collisions with good physical control. However, tight-five performance is dominated by rugby-specific technical and motor learning: scrummaging body mechanics and set-piece stability, specific collision/entry angles, ruck/maul engagement technique, and positional decision-making. These are not meaningfully developed by cycling climbing. Because the transferable component is mainly “fitness + trainability + general lower-body strength endurance,” the expected correlation is small but slightly above zero, with substantial variance (higher in athletes who also have prior strength/contact sport background, or who transition into rugby contact skill early).	[130]
cycling-road-sprinter	0.08	0.06	Cycling road sprinter performance should have a small positive relationship with rugby tight five success mainly via general athletic qualities: explosive force production, repeat-surge capacity, and training discipline/ability to handle demanding sessions. But tight five outcomes are heavily capped by rugby-specific, technique-dominant components—scrum mechanics, leverage, collision handling, and set-piece coordination—which are far from cycling. Therefore the expected correlation is modest (~0.08) with moderate uncertainty (~0.06).	[131] [132] [133]
cycling-road-time-trialist	0.09	0.07	Cycling road time-trialing strongly develops aerobic capacity, pacing, and the ability to produce repeatable lower-body force while staying efficient. Tight five (scrum and close-contact) roles also require high physical conditioning and the ability to sustain repeated collision-related efforts across a match. However, the decisive determinants for tight five success are rugby- and set-piece-specific: scrum technique and body positioning, binding and force-direction mechanics, collision/tackle skill, ruck entry/legalities, and coordinated team execution. Cycling time-trialing does not teach these technical patterns, nor does it simulate scrum mechanics. Therefore the expected correlation is small-to-modest: cyclists may have a head start in conditioning and in learning how to train, but technique/position-specific skill acquisition is the main limiter and produces wide individual variation.	[134] [135]
cycling-track-endurance	0.06	0.05	Tight five rugby is dominated by scrum and close-contact mechanics: repeated collisions, set-piece stability, force transfer, and very specific rugby body positioning/timing. Endurance track cycling contributes mainly sustained effort control and general athleticism, with only indirect overlap through tactical awareness and fatigue resistance. Because the core technical determinants differ strongly, the expected carry-over is small positive (near-zero to low), around ~0.06.	[136] [137] [138] [139]
cycling-track-sprint	0.12	0.08	Sprint track cycling success should correlate only weakly with rugby tight five performance. The overlap is mainly general: producing force quickly, having strong legs/hips, and being able to train hard for peak outputs. However, tight five outcomes are heavily determined by rugby-specific set-piece and collision skills—scrummaging technique, body angle/positioning, binding, ruck/maul contact patterns, and safe repeat-contact mechanics under sustained strain. Cycling sprinting does not train these contact/positioning and technical set-piece skills. As a result, any positive correlation should be small, with large variability by individual adaptation and how quickly the athlete learns scrum/contact technique.	[140]
fencing-epee	0.05	0.06	Epee-to-rugby tight five should be only weakly positive. There is some overlap in general attributes like balance, body control, and making timing/positioning decisions under pressure, which can slightly help with close-range movement and contact readiness. But tight five performance is dominated by event-specific constraints: scrum and lineout techniques, force-and-leverage mechanics, set-piece body positioning, repeated collision/contact skills, and discipline-specific rules for binding/engagement. Those are not meaningfully trained by epee. As a result, the expected technique/cognitive carry-over is small, near ~0.05, with moderate individual variance.	[141] [142] [143]
fencing-foil	0.06	0.08	Foil fencing should have only a small positive correlation with rugby union tight-five success because there is some transferable technique-neutral “combat sense”: staying composed, timing choices in close engagements, and learning under pressure. But tight-five performance is dominated by rugby-specific contact and set-piece mechanics: scrum engagement technique, leverage, force application, collision/tackling skills, and repeated high-force body-on-body sequences coordinated with teammates. Those demands are mechanically and rule-wise very different from non-contact foil’s lunge/point-control system. Therefore the expected carryover is near the lower end of noticeable (small positive), with limited variance: many fencers may bring mental sharpness, but most are bottlenecked by set-piece and collision technique acquisition.	[144] [145] [146]
fencing-sabre	0.03	0.05	Fencing sabre and rugby tight five share only broad components: quick engagement intent, ability to coordinate movement in contact-like confrontations, and mental composure. But tight five performance is dominated by rugby-specific technical determinants: scrum and maul mechanics (binding, leverage angles, driving technique), close-contact collision/footwork under set-piece constraints, and set-piece role execution. Those are not meaningfully trained in fencing. With most of the key “how good you are” variance missing, carry-over should be near the low end. Therefore the correlation should be small, close to 0.00–0.05, with some small positive due to general coordination and competitiveness.	[147]
field-hockey-goalkeeper	0.08	0.06	Field-hockey goalkeeper performance should relate only weakly to rugby union tight-five success. The overlap is mainly general: staying balanced in chaotic situations, reading cues, and performing under physical pressure. However, tight-five roles are dominated by rugby-specific set-piece and close-contact mechanics—scrum/ruck entry patterns, scrummaging body positions, collision/bracing technique, and repeated legally-timed contact actions—which hockey goalkeeping does not develop. With technique dominating the outcome, the skill/technique carry-over should remain small but not zero.	[148] [149] [150]
field-hockey-outfield	0.12	0.07	Field hockey outfield can correlate slightly with rugby union tight five success because both demand athleticism, stamina for repeated phases, and some ability to operate in contact-avoidant but pressure-heavy environments. However, tight five outcomes are driven much more by rugby-specific technical skills: scrum and maul engagement technique, set-piece binding/leg drive sequencing, and specialized collision/tackle/ruck entry mechanics. Hockey outfield does not teach those set-piece and close-contact technical patterns directly. Therefore the expected correlation should be low.	[151] [152]
golf	0.05	0.04	Tight five success in rugby is dominated by scrum mechanics, close-contact collision technique, set-piece stability, and repeated high-force contest execution. Golf success is dominated by precision striking and course-strategy timing, with very different biomechanics and no shared scrum/collision technique. Therefore direct technique carry-over should be very limited. The remaining correlation should come mainly from general transferable components: learning complex rules/techniques, maintaining composure under pressure, and fine body control/co-ordination during repetitive actions. Because tight five performance is also strongly shaped by rugby-specific technical repetition and contest habits, the net carry-over should stay small—around ~0.03–0.08, with an average near ~0.05.	[153] [154]
gymnastics-artistic	0.06	0.04	Artistic gymnastics should correlate positively but only modestly with tight-five (scrum/close-contact) success. Transferable technical components include balance recovery, trunk/hip bracing, controlled body positioning, and learning efficiency for complex whole-body movement patterns. These can help with general collision stabilization and maintaining structure under force. However, tight-five performance is highly rugby-specific: scrum engagement and binding technique, set-piece biomechanics (drive angle, leverage rules), specific foot/hand placement in collisions, and repeated law-governed contact/ruck work dominate. Artistic gymnastics does not train these sport-specific engagement/pack mechanics directly. Therefore the overall skill/technique carryover should be small-to-low (near ~0.06).	[155] [156] [157]
gymnastics-rhythmic	0.08	0.08	Rhythmic gymnastics should correlate positively with rugby tight-five success mainly through transferable “movement-system” skills: excellent balance, proprioception, and controlled whole-body positioning, which can help a player stay stable and coordinate their body when repeatedly engaged and colliding. However, tight-five outcomes are strongly constrained by rugby-specific determinants: set-piece and scrum mechanics (engagement/posture, binding timing), legal ruck/maul technique, and producing high, repeatable collision forces with correct body bracing and leverage. These opponent- and rule-constrained stimulus-response loops are not trained directly by rhythmic gymnastics. Therefore the carryover is small-to-modest positive. A plausible Bayesian mean is ~0.08 with std dev ~0.08 due to large athlete-background variation (many gymnasts won’t have prior rugby/contact training).	[158] [159] [160] [161]
gymnastics-trampoline	0.05	0.05	Trampoline to rugby union tight five should have a weak correlation. The only likely carryover is general neuromotor skill: balance, body awareness, and the ability to control posture through dynamic movements, which can help with basic engagement readiness. However, tight five success is overwhelmingly governed by scrum set-piece mechanics, leverage technique, engagement/body positioning, and repeated collision-specific skills that trampoline does not train. With technique-only framing excluding body-size effects, the net expected correlation should be close to zero to very small—around ~0.05 with moderate uncertainty.	[162] [163] [164] [165]
handball-backcourt	0.08	0.1	Handball backcourt success should correlate only weakly with rugby tight-five success. There is some shared ground in (1) generating force with the upper body and coordinating limbs, (2) understanding timing in collisions/contests and maintaining positioning, and (3) ball-handling basics with hands. But tight five roles are dominated by rugby-specific skills: scrum engagement/binding mechanics, set-piece timing and body angles, ruck/maul contact legality, and repeated heavy collision technique. They also depend more on positional mass/strength and set-piece practice than on perimeter-style passing/shooting. So the correlation is likely positive but small, with large variance—especially for athletes who already have contact/rugby front-row exposure or strong strength/coaching.	[166]
handball-goalkeeper	0.06	0.07	Handball goalkeeper success should have only a small positive correlation with future rugby union tight five success. There is some overlap in general athletic coordination, balance, and readiness to deal with physical contact and rapid decision-making under pressure. However, tight five outcomes are dominated by rugby-specific learned skills: scrummaging/engagement body mechanics, repeated collision technique, and set-piece stability and leverage. Handball goalkeeping does not meaningfully train those sport-specific contact and force-direction skills. Therefore the expected correlation stays low, around ~0.06, with moderate uncertainty.	[167] [168] [169]
handball-pivot	0.2	0.15	A moderate positive carry-over is plausible because both roles are fundamentally about winning and functioning in crowded physical contact and staying effective when space collapses. From handball pivot to rugby tight five, likely transferable components (technique/behavioral) include: (1) maintaining balance and posture while forces act from many angles, (2) learning how to keep position and leverage in congestion, (3) staying composed and reacting in high-pressure sequences, and (4) repeated short bursts of drive and body control. However, the correlation should not be high because tight five success is dominated by rugby-specific tooling: scrum engagement mechanics (binding, body angles, timing), lineout set-piece roles, and the specific tackling/ruck positioning and legality of rugby collisions. Pivot’s dominant “tooling” is hand/ball entry and shooting/space-wrestling near a goal, which does not train the exact scrum/close-contact technique. Thus, the overall average correlation is expected to be positive but only moderate, with high variance: athletes who quickly learn rugby set-piece mechanics will score higher than those whose pivot skillset is mostly ball-dominant and close-to-goal rather than set-piece bodywork.	[170]
handball-wing	0.12	0.1	Handball wing should correlate only modestly with rugby union tight-five success because the shared component is mainly general athleticism: (1) explosive lower-body power, (2) ability to accelerate in short intervals, and (3) some coordination/ball-handling from open play. However, tight-five performance is dominated by very rugby-specific technical skills and repeated collision patterns: (1) set-piece technique (scrum engagement, body positions, bindings, stability), (2) maul/ruck entry and control at close quarters, (3) tackling/leverage timing in high-contact situations, and (4) positional understanding within set-piece structures. These are not trained in the wing role. Therefore the technique/skill-linked carryover is low (close to the “different but athletic” baseline), with some variance depending on whether the athlete also has prior strength/contact experience. Result: average correlation ~0.12 with std dev ~0.10.	[171]
ice-hockey-defenseman	0.17	0.1	Ice hockey defenseman success should correlate modestly with future rugby tight five success because both roles emphasize contact tolerance, body positioning, and repeated collisions where bracing and force application under pressure matter. However, tight five performance is heavily dependent on rugby-specific set-piece and close-contact mechanics—scrum stability, binding/engagement technique, ruck-entry and collision rules, and the particular rhythm of scrum/maul phases. Hockey defense does not teach those exact technical systems, and rugby’s ball-handling/ruck context also differs substantially. Therefore the overall carryover remains modest (positive but not strong), with substantial person-to-person variability depending on how physically/contested-oriented the defenseman’s strengths were versus their skating/transition focus.	[172] [173] [174] [175]
ice-hockey-forward	0.1	0.08	Expect a small positive correlation (~0.10). Hockey forwards likely show transferable general attributes—contact tolerance, whole-body power, and learning to operate in congested spaces. But tight five success is heavily driven by rugby-specific technical learning around scrum/set-piece stability, collision/tackle leverage governed by rugby law, and repeated role-specific footwork at high intensity. Therefore technique-only transfer remains limited and the correlation stays low with substantial uncertainty.	[176] [177]
ice-hockey-goalkeeper	0.08	0.12	Ice hockey goalkeeping should correlate only weakly with rugby union tight five performance. There is some transfer of mental game-reading, composure under pressure, and balance/position-holding habits, but tight five roles are dominated by rugby set-piece and close-contact engagement technique (scrum/maul mechanics, binding, timing of drives) plus specific tackling/collision skills and repeated collision tolerance. These are largely not learned in goalie training. Therefore the expected carry-over is low (near the low end) with substantial variation by athlete adaptability and whether they have complementary strength/set-piece experience.	[178] [179] [180] [181]
judo	0.13	0.1	Judo success should correlate slightly positively with rugby union tight-five success because both emphasize staying stable under heavy contact, using leverage effectively, and maintaining posture and force application during collisions and physical resistance. But tight-five performance is dominated by rugby-specific mechanics: scrum technique (binding/angles/engagement timing), ruck/maul interactions where rules constrain body position, and the exact collision/contact rules. Judo’s grip and off-balancing mechanics don’t directly train the same legal scrum skills and repeated set-piece execution. Therefore the carry-over should be small with meaningful variance depending on how quickly the athlete learns rugby set-piece and collision fundamentals.	[182] [183]
lacrosse-attacker	0.12	0.1	Lacrosse attackers often succeed through perceptual-motor skills and also through operating in close traffic with repeated physical contact: getting to the right spot, maintaining balance under contact, and continuing fast actions after collisions. Those ingredients can help a newcomer learn the general contact demands of rugby tight five roles (set-piece + close-contact collisions). However, tight five performance is dominated by rugby-specific technical mastery: scrum binding/body angles and coordinated leg drive, line-out/maul roles, and very specific ruck/clear-out contact mechanics and legality. Lacrosse attacking mechanics don’t provide a direct template for these set-piece and close-contact techniques. Therefore the relationship should be positive but modest with high variance depending on how quickly the athlete learns rugby contact/set-piece technique and phase rules.	[184] [185] [186]
lacrosse-defender	0.3	0.16	A lacrosse defender who is successful should show a positive correlation with rugby tight five performance because both demand robust close-contact work: maintaining body position, using leverage effectively, absorbing/initiating collisions without losing balance, and staying tactically aware during physical chaos. The correlation is not high because tight five performance is shaped by rugby-specific, highly technical set-piece and collision mechanics (scrum engagement technique, binding/angles, maul work, and phase-specific roles with rugby laws). Lacrosse defense builds physicality and spatial denial, but not the same scrummaging/ruck-driving mechanics or ball-handling constraints. So the expectation is a moderate positive carry-over with substantial uncertainty, depending on how collision-focused the athlete’s lacrosse role was (vs more stick/space-denial) and how quickly they learn rugby set-piece technique.	[187] [188] [189]
lacrosse-goalkeeper	0.06	0.03	Lacrosse goalkeeper success should correlate only slightly with rugby union tight five success. Shared elements are mostly general: concentration, reaction to play changes, and some defensive instincts. But tight five performance is dominated by rugby-specific technical determinants: scrum mechanics and stability, set-piece coordination, repeated collision timing, and force transfer patterns at close range. Lacrosse goalkeeping does not meaningfully train those body-positioning and force-application skills in the scrum/maul context. So the expected correlation is low (near the bottom of “small positive”), likely low single digits with limited upside.	[190]
lacrosse-midfielder	0.12	0.08	Lacrosse midfielders should transfer some general “two-way” qualities into rugby tight five: repeated physical contests, learning to stay coordinated while getting hit, and handling the ball/acting under contact pressure. However, rugby tight five performance is dominated by scrum/set-piece technique and close-contact role-specific skills—binding/engagement mechanics, lineout roles, ruck/maul entry legality, and highly specific body positioning and timing. Those are large “new learning” components with little direct overlap from lacrosse midfielder play. So the correlation should be low-to-modest: ~0.12 on average, with substantial uncertainty (~0.08).	[191]
padel	0.03	0.03	Padel should have only a very small positive relationship with tight-five success. The shared elements are mostly general: athletic coordination, quick perception, and comfort moving in tight spaces during fast sequences. But tight-five performance is largely governed by highly rugby-specific skills: scrummaging technique, body positioning under sustained force, set-piece rules/roles, and collision/ruck mechanics. Those are not practiced in padel. Also, much of the advantage in tight-five comes from force production and collision tolerance, which we treat as largely non-technique/trait factors rather than transferable “skills,” keeping the expected correlation near the low end (~0.00–0.08, centered ~0.03).	[192]
pickleball	0.04	0.04	Pickleball success should correlate slightly with tight-five performance only through general, technique-neutral skills: hand-eye coordination, balance, and cognitive quickness for reacting in chaotic moments. However, tight-five roles in rugby are heavily determined by rugby-specific contact and set-piece mechanics: scrum body positioning and engagement technique, ruck entry/clearance, maul handling, taking/absorbing collisions with correct leverage, and close-contact coordination. Those motor patterns and technical cues are largely absent in pickleball. Because the overlap is small, the correlation should sit near the “different sports” lower range with modest variance between individuals who are especially good at translating general coordination into contact-heavy mechanics.	[193]
rowing-lightweight	0.22	0.09	Lightweight rowing should have a modest positive correlation with rugby union tight five success. The transferable parts are mainly general: whole-body coordination, leverage-style force transmission, and the ability to produce/maintain force efficiently across long periods with repeated intense efforts. However, tight five performance is strongly shaped by rugby-specific determinants with limited rowing overlap: scrum and maul mechanics (binding technique, body angles, timing of drive phases), legal collision/tackling technique, ruck-entry and contact skills, and repeated short explosive bursts with very specific bracing/footwork patterns. Rowing’s cyclic stroke mechanics do not replicate scrum/contact technique or set-piece timing. Therefore the expected carry-over is low-to-moderate (around the low 0.2s) with substantial variance depending on how much complementary strength/contact/sprinting and rugby set-piece practice the athlete adds.	[194]
rowing-openweight	0.22	0.08	Rowing openweight success is driven by coordinated whole-body force production, rhythm/efficiency, and the ability to sustain high output under fatigue. Rugby union tight-five performance also depends on whole-body strength and the capacity to repeatedly generate force and tolerate collisions across matches, plus maintain technical stability in set-pieces and contact sequences. That creates substantial overlap in the “capacity” layer (strength, power repetition, endurance, body control). However, the key determinants of tight-five effectiveness in scrums/close-contact play—scrummaging technique, binding/body position strategy, set-piece timing, and specific ruck/maul engagement mechanics—are highly specific and not trained by rowing’s cyclic stroke. Therefore the correlation should be moderately high (higher than with backs like outside backs/halfbaks), but still capped well below values expected for same-sport transfers because much of the decisive technique is different.	[195] [196] [197]
rugby-union-halfback-midfield	0.6	0.18	Because both positions are in the same sport under the same rules, and both require operating successfully in contact/traffic and learning body control during collisions, success in halfback/midfield should have a fairly strong positive relationship with success in the tight five. However, the tight five’s dominant determinants include scrum and set-piece stability, close-contact engagement mechanics, and repeated collision/tackle contest outcomes in more structured contexts. Halfback/midfield success is more driven by distribution/kicking/phase decision-making and open-field collision balance. That role-emphasis mismatch reduces the correlation from extremely high to moderately high. Allowing for how variable conversion is between backline and front-row/lock-type skill sets within rugby yields a moderate-to-strong expected correlation with a fairly large standard deviation.	[198] [199] [200] [201]
rugby-union-loose-forward	0.66	0.16	Both positions are in the same sport and both require forward contact/physical competition, so transferable rugby “technique/skill behaviors” (body positioning, leverage in contact, decision-making in close quarters, and readiness under repeated collisions) should carry over strongly. However, loose forward and tight five differ a lot in what determines performance: loose forwards are typically judged by open-field work, ruck involvement, and tackle/carry volume, while tight five is judged heavily by set-piece execution (especially scrum/close-contact posture), structural stability, and specialized collision mechanics with different force vectors. Because these role-specific demands account for a meaningful portion of outcomes, the correlation should be high but not near-perfect, with noticeable spread by individual specialization (more mobile/contact-reactive loose forwards translate better into tight-five work than those whose main value is mobility and ball-carrying in broken play).	[202]
rugby-union-outside-back	0.55	0.16	Because both positions are within rugby union, there is substantial shared learning and competitive mindset, plus common contact exposure. That supports a moderate-to-high positive correlation. However, outside backs’ performance determinants (open-field speed, evasion, finishing lines) are quite different from the tight five’s main determinants (scrum/close-contact set-piece stability, specialized force application, coordinated pushing technique, and repeated contact sequences). Those role-specific technical demands create meaningful learning friction, so the relationship should not be extremely high.	[203] [204] [205] [206] [207]
skiing-alpine-speed	0.06	0.07	Alpine speed-event skiing should have a small positive relationship with tight five (scrum/close-contact forward) performance because it builds general athletic foundations that matter in collisions: force absorption, bracing, dynamic balance, and the ability to re-center quickly after high perturbations. However, tight five excellence is dominated by rugby-specific technical constraints: scrum body positions, leverage/engagement mechanics, binding and set-piece timing, plus repeated contact execution under rugby rules. Alpine downhill’s edge/line-holding and force absorption do not teach these sport-specific techniques. Because most of what differentiates top tight five play is sport-specific set-piece mechanics rather than general collision tolerance, the expected carry-over remains small. A realistic estimate is therefore ~0.06 average correlation with ~0.07 std dev, reflecting modest general transfer but large technique/tactics mismatch.	[208] [209] [210]
skiing-alpine-technical	0.08	0.04	Alpine “technical” skiing (slalom/giant slalom) shares some general carry-over with rugby tight five in (1) body control under high external forces, (2) dynamic balance and edge/stance adjustments, and (3) bracing/absorption timing during direction changes. However, the dominant rugby tight five requirements are collision skills, scrummaging mechanics, repeated contact tolerance, and set-piece-specific coordination—much of which is not learned in alpine skiing. Since you asked to exclude physique/traits (e.g., mass advantage), the remaining overlap is mostly neuromuscular control and general force-management, leading to a small positive correlation rather than moderate/high.	[211]
skiing-cross-country	0.06	0.06	Cross-country skiing success is expected to have only a weak relationship with later tight five (scrum/close-contact forward) success. The modest transferable elements are general athletic conditioning: leg/hip coordination, balance, and the ability to keep working under fatigue—useful for repeated contact and sustained set-piece workload. However, tight five performance is dominated by rugby-specific technical skills: scrum technique and body positioning, ruck/maul engagement mechanics, collision bracing, and highly specific strength/force-production patterns in contact. Endurance-focused skiing does not directly train scrum mechanics or the technical “how” of repeated collisions in a rugby context. Thus the expected average correlation is low (~0.06) with moderate uncertainty; it could be somewhat higher for skiers who also trained heavy strength/power and contact/collision movement practice, and lower for purely aerobic ski backgrounds.	[212]
snowboarding	0.03	0.02	Snowboarding should have very limited carry-over to rugby union tight five roles. There is a small general transfer via body control and balance under movement/impact-like moments, which can help with set-piece stability and maintaining posture while force is applied. But tight five success is dominated by rugby-specific mechanics: scrum engagement technique (body position, binding, leverage and timing), collision/contact patterns, and repeated set-piece execution. Snowboarding’s edge control and aerial skills do not train the required scrummaging technique or the specific high-force contact tolerances and biomechanics. So a near-zero positive correlation is most realistic.	[213]
soccer-central-defender	0.25	0.12	A central defender’s success should correlate positively with rugby union tight-five success because both roles require working effectively in heavy physical contests and maintaining body control under repeated contact. Central defenders also tend to develop strong positioning habits and the ability to win space in aerial/close duels—helpful as a set-piece forward who must stabilize and compete in tight zones. However, tight-five performance is dominated by rugby-specific mechanics: scrum technique, binding/engagement rules, set-piece coordination, and rugby-ball/ruck context. Soccer defending does not train those exact patterns, so the correlation should be moderate rather than high.	[214] [215] [216]
soccer-central-midfielder	0.18	0.1	Soccer central midfield success should transfer somewhat to rugby tight five through general athleticism, contact tolerance/dueling experience, and the ability to operate in tight, congested spaces with good game sense. That supports a low-to-moderate correlation. However, tight five performance is dominated by rugby-specific set-piece and close-contact technical skills (scrum mechanics and role execution, lineout work, breakdown body positions) and specialized collision/force-application patterns. Because those are not meaningfully trained by soccer midfield, the correlation cannot be high.	[217]
soccer-goalkeeper	0.12	0.12	Soccer goalkeeping should correlate only modestly with rugby union tight five success. The overlap is mainly in broad perceptual composure and the ability to execute decisions reliably under pressure. But tight five is dominated by rugby-specific learned techniques (scrum/lineout mechanics, set-piece body positioning, ruck/maul contact, and repeated collision timing). Those core motor patterns are not trained in goalkeeping, so carry-over remains small and inconsistent; contact demands add substantial between-person variability.	[218] [219] [220]
soccer-striker	0.12	0.1	Soccer striker performance may correlate slightly with rugby tight five success because both involve high physical intensity, explosive leg drive, and performing effectively in contested areas. But tight five roles are heavily determined by rugby-specific skills: scrum positioning and technique, set-piece mechanics, body leverage in collisions, and safe/illegal-contact constraints at close range. Soccer striker play is mostly open-field attacking with striking/finishing mechanics, not repeated scrum/collision technique. Therefore the expected carry-over is low and positive, around ~0.12, with substantial uncertainty.	[221] [222]
soccer-winger	0.12	0.08	Soccer winger success should have a small positive relationship with rugby union tight five success, mainly through general athleticism (ability to work hard repeatedly, competitive mindset, and some mobility). However, tight five performance is governed by rugby-specific technical contact and set-piece mechanics—scrum stability, binding/foot placement, collision technique, and repeated close-contact decision patterns. These are largely absent from winger soccer training. Because most of what matters is new learning, the correlation should be low (around the low-0.10 range). I set the average at ~0.12 with moderate uncertainty, reflecting that some wingers with a strong physical/contact-ready background may adapt faster, while others will not.	[223]
softball-catcher	0.03	0.04	Softball catcher success should have only a very weak relationship with rugby union tight five success. There is slight overlap in general athletic attributes like anticipation, coordination, and staying composed in repeated high-pressure moments. However, tight five performance is dominated by rugby-specific contact/set-piece techniques: scrum stability and binding, lineout/maul roles, collision timing and body positioning in confined space, and the specific biomechanics of repeated collisions. Catcher training does not develop these core mechanics, so the correlation remains low positive, close to the 0.00–0.05 range.	[224]
softball-field-player	0.12	0.09	Softball field-player success should have a modest positive relationship with rugby tight five success because both can involve general field-athlete skills: reading play, reacting quickly, and basic ball-handling/coordination. However, tight five performance is dominated by rugby-specific technique: scrum and lineout set-piece body mechanics (binding, engagement timing, force distribution), close-contact ruck/maul skills, and tackling/collision execution within rugby laws. These are not core softball skills. Since we exclude body-proportion advantages, there is still some positive transfer via general athleticism, but the expected carryover stays low-to-modest.	[225] [226] [227]
softball-pitcher	0.05	0.07	A softball pitcher has some transferable ingredients for rugby: (1) coordinated force transfer through the kinetic chain, (2) comfort generating force in structured mechanics, and (3) coping with repeated high-intensity work. However, tight five success is heavily determined by scrum and close-contact technique (set-piece binding/positioning), collision timing, maul/ruck body angles, and very specific contact and stability skills. Those are only weakly related to underhand pitching. Therefore the expected correlation is small positive, close to a “wildly different” baseline but not zero due to general force-generation and repetition under fatigue.	[228]
squash	0.04	0.04	Tight five performance in rugby union is heavily determined by set-piece-specific technical execution (scrum stability/binding, body position and force application sequence), collision/contact rules, and repeated high-force engagement mechanics. Squash can transfer some general athletic qualities like balance, stamina, and lateral footwork, but those do not meaningfully map to scrum mechanics or close-contact set-piece technique. Therefore the correlation between success in squash and success in tight five roles should be very small.	[229]
surfing	0.06	0.05	Surfing should have only a small positive carryover to rugby union tight-five roles because the shared “skill substrate” is limited. Surfing can help with (1) dynamic balance and posture control, (2) coordination while recovering from instability, and (3) tolerance for repeated high-effort bouts. But tight-five performance is largely determined by sport-specific contact and set-piece mechanics: scrum body positioning and binding, repeatable driving/engagement technique, lineout/maul role execution, tackling/leverage in close quarters, and set-piece timing—none of which are directly practiced in surfing. Because most determinants are rugby-specific, the expected correlation is low: ~0.06 with moderate uncertainty (~0.05).	[230]
swimming-backstroke-middle-distance	0.05	0.04	Backstroke middle-distance success is largely driven by efficient propulsion mechanics, shoulder/upper-body endurance, rhythm/pacing, and precise execution of starts/turns/underwater work repeatedly under fatigue. Rugby tight five success is dominated by set-piece and contact-specific skills: scrum technique (binding, leverage, coordinated leg drive), repeated collisions, ruck/maul entry and body positioning, and close-contact decision-making under structured rules. After excluding body-proportion traits, there is still only limited transferable technique content from backstroke to scrum/set-piece mechanics. The main carry-over is general: learning technique from coaching, conditioning for repeated high-effort bouts, and staying composed through physical stress. Because collision/set-piece mechanics are highly rugby-specific and not practiced in backstroke, the correlation should be very low. Thus a realistic expected correlation is around ~0.05 with modest uncertainty.	[231] [232]
swimming-backstroke-sprint	0.06	0.05	Sprint backstroke success is driven mainly by explosive starts, efficient turns/underwater work, shoulder–trunk sequencing, and maintaining high-tempo technique under short anaerobic stress. Rugby union tight five roles depend heavily on sport-specific learned skills: scrum engagement/binding, set-piece positioning, and effective collision/ruck-entry mechanics. Those technique domains are largely absent from sprint backstroke. There is some transferable athletic substrate—quick initiation, whole-body coordination, and the ability to execute technically precise actions repeatedly while fatigued. But the key determinants for tight five performance are set-piece and contact mechanics and timing, so the carry-over should remain small. A realistic expected correlation is therefore around r ≈ 0.06 with std dev ≈ 0.05, allowing for modest upside in particularly adaptable athletes while keeping the overall prediction low.	[233] [234] [235]
swimming-breaststroke-middle-distance	0.03	0.04	Middle-distance breaststroke success is driven by precise simultaneous arm–leg timing, rhythm/efficiency, and maintaining repeatable propulsion mechanics under speed-endurance fatigue. Rugby tight five roles require set-piece and scrum technique, close-contact body positioning, collision/tackling mechanics, leverage, and repeated high-force impacts, plus set-piece stability. There is only limited overlap in general attributes: maintaining technique under fatigue and coping with repeated high-effort bouts. However, the core tight-five skills—scrum mechanics, maul/ruck contact technique, and collision-leverage—are largely not trained in breaststroke. Therefore the expected correlation is very small but slightly positive: ~0.03 with uncertainty ~0.04.	[236] [237]
swimming-breaststroke-sprint	0.06	0.05	Sprint breaststroke success is largely about explosive whole-body timing (kick+pull synchronization), strong starts/turn acceleration, and maintaining technique rhythm across short maximal bouts. Tight five rugby (scrum/close-contact) also involves repeated high-effort bursts and whole-body coordination, but the decisive technical learning is rugby-specific: scrum engagement mechanics, ruck/maul body positioning, collision/tackling/contact protection technique, and set-piece and close-contact handling under pressure. Those perceptual-motor and rules/technique components are not trained in breaststroke. With physique-based predispositions excluded, the remaining overlap is mostly general effort-tolerance and coordination habit rather than direct skill translation. Therefore only a small positive correlation is expected, near the lower end.	[238]
swimming-butterfly-middle-distance	0.06	0.08	Butterfly middle-distance success reflects strong whole-body coordination, rhythm, and the ability to maintain technical quality while fatigued through repeated high-intensity efforts. Tight five roles in rugby (scrum/close-contact forward work) also require physical coordination and repeatability under fatigue, plus the ability to execute correct movement patterns while under heavy contact stress. However, the core skill bottlenecks are very different: tight five performance is driven largely by scrum and set-piece techniques (binding/angles, drive mechanics, body positioning), lineout/ruck maul roles, and close-range collision/tackling mechanics tied to rugby law and team timing. Butterfly swimming does not train those specific motor programs or perceptual-cognitive demands. Therefore the transferable component is mainly general athletic coordination and learning/consistency, not a direct advantage in the technical determinants of tight five play. That pushes the expected correlation to a very low level. Mean ~0.06 with std dev ~0.08 captures that some swimmers may cross-train with strength/contact/ruck mechanics (raising transfer), while many will not.	[239]
swimming-butterfly-sprint	0.07	0.07	Sprint butterfly performance should have only a weak positive correlation with tight-five rugby success. The overlap is mainly general: whole-body coordination, ability to generate force quickly, and keeping mechanics cleaner when fatigued—useful across the repeated collision volume. However, tight-five roles are highly determined by rugby-specific contact and set-piece technique: scrum binding/engagement mechanics, body angles/leverage, timing of pushes and collisions, and safe high-force contact skills. Butterfly swimming does not train these interaction-specific patterns. Also, successful tight-five play is affected strongly by build/strength outcomes that we are not counting here, further reducing the expected technique-only correlation. Therefore the correlation remains small with relatively high variance across individuals who may have strong general collision tolerance and learn scrum skills quickly versus those who do not.	[240] [241]
swimming-freestyle-distance	0.05	0.05	Endurance-heavy freestyle swimming can correlate slightly with later rugby tight-five performance through transferable basics: cardiovascular fitness, repeat-effort tolerance, general athletic coordination, and the habit of drilling technique consistently. However, tight five (scrum/close-contact forward) performance is dominated by sport-specific determinants: scrum body positioning and technique, set-piece timing, binding/engagement mechanics, ruck/maul physical roles, and collision/contact technique (bracing, driving through force, maintaining stability under load). Front-crawl distance swimming does not provide meaningful learning for these set-piece and contact mechanics, and it emphasizes continuous propulsion rather than producing and absorbing forces in the specific rugby contexts. Therefore the carry-over should be small—positive but near the baseline for very different sports.	[242]
swimming-freestyle-middle-distance	0.02	0.04	Freestyle middle-distance swimming can carry over indirectly to rugby because it develops cardiovascular endurance, repeated high-quality movement under fatigue, and general body control. Those can help a player endure a match and recover between physical phases. But tight five performance is dominated by rugby-specific technical skills: scrum engagement mechanics, close-contact binding/foot placement, lineout/maul roles, efficient collision/tackle technique, and set-piece timing/coordination with teammates. Swimming does not train these constrained, opponent-and-rules-dependent contact patterns, nor the specific force-direction skills of scrum driving. Therefore the carry-over from being good in swimming to succeeding in tight five is expected to be near-zero but not negative—mainly due to general athleticism and training discipline—yielding a low-positive correlation around ~0.02 with small uncertainty.	[243]
swimming-freestyle-sprint	0.05	0.07	Sprint freestyle swimming could correlate slightly with tight-five success because both involve repeated high-intensity efforts, strong coordination, and producing force quickly. But tight five performance is heavily determined by rugby-specific set-piece technique (scrum engagement, body angles, binding/hand placement, maul positioning), and by collision/contact skills and timing (tackling/entry mechanics). Swimming sprint freestyle doesn’t teach those scrummaging/close-contact mechanics, so the carry-over should remain low.	[244]
table-tennis	0.05	0.04	Table tennis success indicates strong perceptual timing, hand-eye coordination, and the ability to execute precise short explosive movements. These can correlate slightly with rugby because tight-five players must still coordinate body positions, react to set-piece dynamics, and execute repeatable technical movements. However, tight five roles are largely determined by rugby-specific high-force mechanics: scrum engagement technique and leverage, lineout/maul roles, repeated collisions, and ball security/pressure handling in close quarters. Table tennis does not train the technical pathways for scrums/mauls or the physical collision skillset (even when ignoring body proportions). Because of this weak technical mapping, the carry-over should be very small.	[245]
taekwondo	0.05	0.06	Tight five rugby performance depends heavily on rugby-specific set-piece mechanics and close-contact technical execution (scrum and maul body positions, engagement timing, ruck/maul legality, and collision entry angles). Taekwondo can contribute some general athletic abilities (balance, hip/leg strength, and mental readiness for impact), but it does not teach the core technical patterns needed for scrum/maul roles. Therefore carry-over should be near the “very different” end. Estimated correlation: ~0.05 with moderate uncertainty (~0.06 std dev).	[246] [247] [248]
tennis	0.06	0.06	Tennis success should correlate only weakly with rugby union tight five success. While there’s some general transfer (athletic coordination, willingness to train, basic collision tolerance), the decisive factors for tight five—scrum mechanics, set-piece stability and binding/engagement technique, and rugby-specific collision/contact skills—are largely sport-specific and not learned in tennis. Therefore an expected correlation is near the low end, around ~0.06 with a similar magnitude of uncertainty (~0.06).	[249] [250] [251]
triathlon	0.06	0.05	Triathlon performance is dominated by aerobic conditioning, pacing, and efficient movement mechanics across swim/bike/run. Tight five (scrum/close-contact) performance depends much more on set-piece mechanics (scrummaging technique, body positioning), repeat-collision execution, short explosive strength, and specific contact/ruck skills. The overlap that can transfer is mainly (1) endurance of effort across long matches and training, (2) staying composed and keeping form under fatigue, and (3) general athletic conditioning from multi-discipline work. However, triathlon provides little practice for the defining technical determinants of tight five: scrum engagement mechanics, sustained force in a braced position, footwork for close contact, and collision/ruck technique in the tackle/contest cycle. Because physique/proportion effects are excluded, the correlation should remain small. Therefore a low positive correlation with noticeable variance is plausible—higher for athletes who already have rugby/contact training alongside triathlon.	[252]
volleyball-attacker	0.05	0.04	Volleyball attacker success should correlate only very weakly with rugby tight-five success. There is a small shared component: both demand power bursts, coordination, and willingness to engage physically. But tight-five performance is dominated by rugby-specific set-piece and collision mechanics: scrummaging technique (binding, posture, drive angles), ruck/maul engagement, and repeat collision/body positioning—none of which volleyball attackers train in the same way. Because most of the skill overlap is missing (and we’re excluding body-proportion effects), the carryover remains near the low end. Chosen estimate: 0.05 with low uncertainty.	[253]
volleyball-libero	0.02	0.03	A volleyball libero’s technique is primarily reception/digging, quick defensive reading, and efficient back-court movement. A rugby union “tight five” role is heavily defined by scrum set-piece technique, close-contact engagement, and collision-specific force application. While there can be some general overlap in balance, movement awareness, and handling pressure, the dominant determinants for tight five success are rugby-specific contact/set-piece mechanics and force production patterns. Since this is a technique-only correlation (excluding body build advantages), carry-over should be very small—close to zero with limited upside—around 0.02 with moderate uncertainty.	[254] [255]
volleyball-middle-blocker	0.07	0.06	Volleyball middle blockers and rugby tight five roles share only limited, technique-independent components: forceful physical engagement, timing, and spatial awareness in congested play. However, tight five success is driven by rugby-specific close-contact and set-piece skills: scrum technique and stability, binding/hand placement laws, repeated collision mechanics (tackle/ruck entry/body angle), and disciplined contact positioning. Volleyball blocking/quick-attack skills don’t map directly to scrum mechanics or legal engagement patterns. Because the overlap is mostly general athletic competence rather than role-specific technique, the correlation should be low (positive but close to zero).	[256]
volleyball-setter	0.04	0.05	Volleyball setter success should have only a very small positive correlation with rugby tight five success. The main overlap is general athletic coordination, spatial awareness, and decision-making under pressure. But tight five performance is dominated by rugby-specific set-piece mechanics (scrum positioning and stability), collision/tackle technique, and repeated high-force body contact at close range. Volleyball setting does not train the key scrum/contact skills, so carry-over is minimal.	[257]
wrestling	0.08	0.07	Wrestling should provide some transferable advantages to rugby union tight five because both involve sustained close-body contact, leverage, and body-position control while being resisted. That can help with general stability, staying upright, and learning how to use leverage in collisions. However, tight five performance is dominated by rugby-specific set-piece and collision legality/technique: scrum engagement and drive mechanics, binding and coordinated forward movement, ruck/maul responsibilities, and repeated rugby-legal collisions. Wrestling success does not directly train these core event- and rule-specific mechanics. So the expected carry-over is small but positive. A plausible estimate is ~0.08 average with fairly wide uncertainty, reflecting that some wrestlers with exceptional body-control skills adapt quickly to scrum contact, while many still need large rugby-specific technical retraining.	[258] [259] [260]

Sources

Measurements sources

#	Title	Authors	Year	Publisher	Use	URL
[1]	Elite female rugby player characteristics (forwards vs backs benchmarks)	Authors n/a	2021 (article) / 2020 (study cited)	FEEPO (summarizes Posthumus et al., 2020)	Used forwards benchmark as an anchor for tight five height: forwards mean height ~176 cm; tight five typically sits at the upper/more set-piece–oriented end of forwards, so height is modeled slightly higher (~180 cm).	Open source
[2]	The Physical Characteristics of Elite Female Rugby Union Players (DXA study; PMC full text)	Authors n/a	2020	PMC (Posthumus et al., 2020)	Supports that elite female RU forwards are taller/heavier than backs, consistent with using a forwards-based height anchor for tight five.	Open source
[3]	Height in sports (general arm-span/height proportionality & ape index context)	Authors n/a	n/a	Wikipedia	Used as a proportional prior: arm span is often close to height; tight five benefits from reach for contact and set-piece positioning.	Open source
[4]	Anthropometric segment proportionality reference (inseam proxy)	Authors n/a	n/a	Wright State University anthropometry/segment table (proxy)	Used only as a proxy to keep inseam consistent with the chosen stature when rugby tight-five inseam means aren’t publicly available.	Open source
[5]	Derived internal consistency (inseam / torso length)	Authors n/a	n/a	Derived metric	Computed from leg_inseam_average and torso_length_average for proportional consistency.	Open source
[6]	Anthropometric width proportionality reference (pelvic breadth proxy)	Authors n/a	n/a	Wright State University anthropometry/segment/width table (proxy)	Used to keep pelvis breadth consistent/plausible relative to height and shoulder breadth proxy values.	Open source
[7]	Derived internal consistency (shoulder width / pelvic breadth)	Authors n/a	n/a	Derived metric	Computed from the selected shoulder_width_average and pelvic_bone_width_average to ensure internal anthropometric plausibility.	Open source
[8]	Ideal shoulder size calculator (height-based shoulder breadth proxy)	Authors n/a	2026	Better Life Fitness	Used as a coarse proxy to generate shoulder width dimensions consistent with chosen height.	Open source
[9]	Anthropometric segment proportionality reference (torso length proxy)	Authors n/a	n/a	Wright State University anthropometry/segment table (proxy)	Proxy used to model torso length consistent with chosen height/segment proportions.	Open source
[10]	Ankle girth baseline (adult proxy)	Authors n/a	n/a	Topend Sports	Used as a general adult proxy; rugby tight-five-specific ankle circumference distributions aren’t usually published.	Open source
[11]	Height in sports (ape index / arm-span proportionality context)	Authors n/a	n/a	Wikipedia	Used as a generic proportional prior for ape index near 1.	Open source
[12]	Foot (unit) (proportional foot length guidance)	Authors n/a	n/a	Wikipedia	Rule-of-thumb proportional guidance for foot length relative to height; used because position-specific cleat-fit means aren’t publicly available.	Open source
[13]	Average hand size / hand length (adult baseline)	Authors n/a	2018	Healthline	Used as a realistic adult-athlete baseline proxy; rugby tight-five-specific hand-length distributions aren’t consistently published.	Open source
[14]	Circumference baseline proxy reference (girth test)	Authors n/a	n/a	Topend Sports (girth/circumference reference page)	Coarse adult baseline proxy used for wrist circumference.	Open source

Traits sources

#	Title	Authors	Year	Publisher	Use	URL
[15]	Elite rugby anthropometry/physiology overview (set-piece + collision + repeated intensity demands)	Authors n/a	n/a	Open University Research Online (JSCR accepted paper)	Demand-based inference: tight five needs explosive force in collisions/scrums but also repeated high-intensity efforts across match duration, motivating a balanced rather than purely fast-twitch archetype.	Open source
[16]	Elite female rugby player characteristics (forwards vs backs benchmark: heavier/more body fat in forwards)	Authors n/a	2021 (article) / 2020 (study cited)	FEEPO (summarizes Posthumus et al., 2020)	Forwards (including tight five roles) are heavier than backs; used to justify a larger, mass-retaining metabolic/body-composition tendency as a prior for tight five.	Open source
[17]	Rugby elite anthropometry/physiology overview (contact stability inference)	Authors n/a	n/a	Open University Research Online (JSCR accepted paper)	Inference: tight five scrums/mauls and repeated collisions require joint stiffness/force transfer efficiency and stability over extreme flexibility; thus low laxity prior.	Open source
[18]	Foot/ankle mechanics baseline for cleated contact sports (proxy)	Authors n/a	n/a	Topend Sports (context + baseline testing reference)	Used as a pragmatic biomechanics prior for cleated field sports where neutral mechanics tend to balance stability and force transfer.	Open source
[19]	Outdoor intermittent exertion general physiology (reasoning prior)	Authors n/a	n/a	Exercise physiology general prior	Used as a reasoning prior (no tight-five-specific temperature-tolerance study used): rugby union is outdoor and variable, so balanced thermoregulation is safest.	Open source
[20]	Dominant handedness/side advantage is largely individual/skill-system dependent (prior)	Authors n/a	n/a	Reasoned prior	Set to neutral because robust evidence for a consistent league-level right/left positional advantage specifically for tight five isn’t used.	Open source

Goals sources

#	Title	Authors	Year	Publisher	Use	URL
[21]	Force production during the sustained phase of Rugby scrums: a systematic literature review	Force production during the sustained phase of Rugby scrums: a systematic literature review	2020	BMC Sports Science, Medicine and Rehabilitation	Used to support that scrummaging technique and force production are teachable and improves via coaching—key for confidence-building.	Open source
[22]	The Incidence of Injury in Amateur Male Rugby Union: A Systematic Review and Meta-Analysis	K. (et al.)	2018	PMC / Sports Medicine	Used to acknowledge injury risk can undermine confidence progression for some amateurs.	Open source
[23]	World Rugby Passport – Movement classification	World Rugby Passport	n.d.	World Rugby Passport	Used to indicate rugby involves repeated high-intensity efforts rather than steady-state endurance-only work.	Open source
[24]	World Rugby Passport – Movement classification / set-piece demands	World Rugby Passport	n.d.	World Rugby Passport	Used to anchor that scrums are a set piece central to how tight five play (supporting that their work is structurally force-based).	Open source
[25]	Spinal injuries in professional rugby union: a prospective cohort study	Spinal injuries in professional rugby union: a prospective cohort study	2007	PubMed	Used to provide context that scrummaging/tackling expose players to meaningful mechanical injury risk—part of why the challenge is serious.	Open source
[26]	Quantifying Collision Frequency and Intensity in Rugby Union and Rugby Sevens: A Systematic Review	(collision frequency/intensity context)	2022	PMC	Used to support that collisions/contact actions are central; coaches can use these to evaluate performance, though individual amateur self-benchmarking may be less straightforward.	Open source
[27]	World Rugby Passport – Movement classification	World Rugby Passport	n.d.	World Rugby Passport	Used to support that locomotion/acceleration demands differ by role, lowering the expected agility alignment for tight five.	Open source
[28]	A review of physical and physiological demands of rugby (context for conditioning adaptations)	Gabbett	2023	Physical Activity Review (PDF)	Supports that rugby training/matches create broad physical conditioning demands across endurance and repeated high-intensity efforts.	Open source
[29]	World Rugby Passport – Movement classification (contact/collision and locomotion demands)	World Rugby Passport	n.d.	World Rugby Passport	Used to support that rugby match demands include repeated high-load contacts/collisions and locomotion.	Open source
[30]	World Rugby Passport – Movement classification (role-dependent locomotion patterns)	World Rugby Passport	n.d.	World Rugby Passport	Used to support that rugby demands vary by role: tight-five are more collision/set-piece oriented than speed-oriented.	Open source
[31]	World Rugby Passport – Definitions (scrum/set-piece terms)	World Rugby	n.d.	World Rugby Passport	Used to anchor that scrums are formal set-pieces central to tight-five skill work.	Open source

Preferences sources

#	Title	Authors	Year	Publisher	Use	URL
[32]	Rugby union	Wikipedia contributors	n/a	Wikipedia	Supports that rugby is played as competitive matches with point scoring.	Open source
[33]	Movement Demands and Injury Characteristics in Under-20-Years University Rugby Union Players	PMC (peer-reviewed article)	2019 (approx.)	PubMed Central	Used to support that injury-relevant contact demands are part of rugby union match play.	Open source
[34]	Contact load is associated with both contact and non-contact injuries in rugby union	Frontiers in Physiology	2025	Frontiers in Physiology	Used to emphasize that contact load is substantial in rugby overall (context for why contact-focused roles fit the sport).	Open source
[35]	Movement and physical demands of school and university rugby union match-play in England	BMJ Open Sport & Exercise Medicine	n/a (article year not in snippet)	BMJ Open Sport & Exercise Medicine	Used to support that rugby match-play includes intermittent efforts rather than continuous steady work.	Open source
[36]	An Analysis of Repeated High Intensity Efforts (RHIE) across Different Competition Levels in Elite Rugby Union	PMC (peer-reviewed article)	2022 (approx.)	PubMed Central	Supports rugby’s intermittent high-intensity demand profile.	Open source
[37]	Scrum (rugby union)	Wikipedia contributors	n/a	Wikipedia	Used to justify that the scrum outcome is collective coordination.	Open source
[38]	Rugby union positions	Wikipedia contributors	n/a	Wikipedia	Supports that tight five responsibilities are tied to set-piece work.	Open source
[39]	Age grade contact training (guidance)	England Rugby (RFU) coaching resource	published last year (per crawl)	England Rugby	Supports that rugby practices include tackle/ruck/scrum/maul style contact elements that coaches manage as contact load.	Open source
[40]	Rugby union gameplay	Wikipedia contributors	n/a	Wikipedia	Used to support that rugby’s phases (including forward set pieces) occur on the field.	Open source
[41]	Physical conditioning for rugby – An Evidence-based literature review	Evidence-based conditioning review (PDF)	n/a (PDF)	Springboks.rugby (PDF)	Supports that rugby training targets high-intensity physical qualities (consistent with explosive/force bursts).	Open source

Injuries sources

#	Title	Authors	Year	Publisher	Use	URL
[42]	Epidemiology of time-loss injuries in English community-level rugby union	Authors n/a	2013	BMJ Open	Used to support that rugby lower-limb injuries are common overall (plausibility for Achilles-region issues), while shoulder/head/neck are also important competing burdens.	Open source
[43]	Load progression criteria in exercise programmes in lower limb tendinopathy: a systematic review	Authors n/a	2020	BMJ Open	Used for the principle that tendon outcomes relate to appropriate progressive loading, limiting how much benefit can be credited to rugby alone.	Open source
[44]	The effectiveness of proprioceptive training in preventing ankle sprains in sporting populations: A systematic review and meta-analysis	Authors n/a	2014	Sports Medicine (via ScienceDirect listing)	Provides evidence that proprioceptive training helps; applied cautiously because the question limits us to rugby participation alone.	Open source
[45]	Rugby Injury Imaging / injury patterns summary	Authors n/a	(recent article page)	PMC	Provides context that shoulder and other regions are prominent; used to keep hand/finger impact risk conservative for tight five.	Open source
[46]	IRIS Clubs Season Report (men’s clubs): hip & groin among common injury regions	Authors n/a	2017-2018	Irish Rugby Injury Surveillance Project (IRIS)	Used to support that hip/groin is among common injury regions in rugby, justifying high risk for a contact-heavy role.	Open source
[47]	Hamstrings injury incidence, risk factors, and prevention in Rugby Union players: a systematic review	Authors n/a	2021	PubMed	Used as general context for rugby-related muscle injury patterns where targeted prevention beyond playing is often needed, limiting prevention attribution from rugby alone.	Open source
[48]	Spinal injuries in professional rugby union: a prospective cohort study	Authors n/a	2007	PubMed	Used to support that rugby exposes players to substantial spinal injury risk during tackling/scrummaging, justifying high low-back pain risk plausibility.	Open source
[49]	Incidence, severity, aetiology and type of neck injury in men's amateur rugby union: a prospective cohort study	Authors n/a	2009	Chiropractic & Manual Therapies	Used to support that front-row/tight-five related positions have high neck injury counts, reinforcing that front-row contact exposure is very high (co-occurring with shoulder loading).	Open source

Past-sport transfer sources

#	Title	Authors	Year	Publisher	Use	URL
[50]	Shared collision-contact demands (tackling readiness, bracing)	—	—	Sports science/transfer synthesis	Supports a moderate-positive correlation because both defensive backs and tight five roles experience frequent physical contact, require bracing, and must maintain balance and body control through collisions.	Open source
[51]	Role mismatch: open-field pursuit vs set-piece scrum mechanics	—	—	Biomechanics/skill specificity synthesis	Reduces correlation because tight five performance hinges on scrum/lineout set-piece technique (body positioning, pushing/leverage coordination, and repeated collision within rules) that defensive back play doesn’t train directly.	Open source
[52]	Different conditioning and movement pattern constraints	—	—	Exercise physiology/transfer synthesis	Adds reduction because defensive back work is dominated by reactive coverage and sprint/stop/cut mechanics, while tight five involves very different repeated collision patterns and largely different force application and pacing within set pieces.	Open source
[53]	Learning/adaptation under coaching and high-pressure training	—	—	Sports psychology/transfer synthesis	Adds a small boost because elite football defenders are accustomed to complex schemes, coaching feedback, and high-intensity physical preparation, helping adaptation to rugby contacts.	Open source
[54]	Transfer of learning: shared collision/force-production and set-piece contact	—	—	Sports science generalization	Used to justify a fairly strong positive correlation because both roles emphasize repeated physical collisions, body positioning, and producing/absorbing force in close quarters.	Open source
[55]	Practice specificity and rule/skill differences across contact sport roles	—	—	Sports science generalization	Used to limit correlation since rugby tight five relies heavily on scrum-specific technique, binding/engagement laws, and set-piece timing not present in American football line play.	Open source
[56]	Transfer increases for shared high-contact, high-strength set-piece/body-control demands	Zimmerman, Schmidt	N/A	Motor learning / skill transfer theory (domain knowledge)	Used to justify a moderate-to-strong correlation because both LB/TE and tight five require frequent body collisions, leverage, and force production with strong body positioning.	Open source
[57]	Tight five success is dominated by set-piece technique and role-specific binding/drive mechanics	Rugby union coaching heuristics	N/A	Coaching/domain knowledge	Reduced correlation: rugby tight five outcomes depend heavily on scrum/lineout specifics (binding, footwork within the pack, stability under repeated set-piece force, laws-dependent positioning) that differ from football LB/TE outputs.	Open source
[58]	Pad leverage vs scrum/ruck contact differ enough to cap transfer	Movement-pattern specificity heuristics	N/A	Movement/skill specificity (domain knowledge)	Adjusted downward because football’s engagement (tackling/blocking) and LB/TE tactical contact patterns are not the same as scrum engagement and repeated set-piece collision mechanics.	Open source
[59]	Transfer of learning in contact team sports (general transfer)	Shared rugby invasion/contact environment transfer (general physical decision/positioning)	2026	Sports science heuristics	Used to set a moderate baseline because both roles operate in a collision-heavy, team decision context and develop general skills like reading phases and positioning under pressure.	Open source
[60]	Quarterback vs rugby tight five: different motor-skill and set-piece technical stack	Large technical mismatch: QB passing/pocket vs tight five set-piece collision mechanics	2026	Rugby coaching/position knowledge	Used to reduce the correlation because tight five success depends heavily on scrummaging biomechanics, set-piece technique, ruck/maul roles, repeated high-contact collision execution, and strength/leverage demands that quarterbacks don’t train as primary techniques.	Open source
[61]	Plausible cross-transfer from American football WR/RB to rugby union tight five	Assumed from general sport-transfer principles (no single paper)	2026	Internal sports science reasoning	Chose a low positive correlation because both contexts include contact and collision tolerance, and WR/RB success can indicate general athletic contact balance and aggressive movement. But tight five performance is dominated by rugby-specific technical mechanics (scrum engagement/posture, binding, pushing mechanics, set-piece timing), close-contact forward skills (clearing/ruck-entry patterns, maul stability depending on role), and power applied in constrained biomechanics. Those are not trained in WR/RB roles, so carry-over should be limited.	Open source
[62]	Distance running success → repeated effort tolerance for close-contact forwards	Endurance/work capacity transfer	n/a	Sports science synthesis (no single canonical study)	Tight-five roles require sustained involvement across phases and high collision volume; distance specialization should give a small advantage in aerobic base, fatigue resistance, and maintaining effort in long matches/practices.	Open source
[63]	Distance specialization vs scrum force production and set-piece stability	Core mismatch: maximal force + set-piece technique	n/a	Sports science synthesis (no single canonical study)	Tight-five performance is heavily driven by scrum/lineout mechanics, maximal strength, and set-piece technical stability—qualities not trained by distance events (which emphasize aerobic economy rather than maximal force application). This caps the correlation.	Open source
[64]	Contact biomechanics specificity limits transfer	Collision mechanics specificity	n/a	Sports science synthesis (no single canonical study)	While both involve running and movement, rugby tight-five collision and engagement mechanics (body position, leverage, bracing, repeated impacts) are sport-specific, increasing variability and reducing predictive power.	Open source
[65]	Shared explosiveness and body control under force	—	—	—	Supports a modest positive correlation because high jump indicates elastic leg/hip power and body control that can help with burst power, bracing, and repeated collisions at least in the athletic component of tight five roles.	Open source
[66]	Tight five is set-piece/contact-technique specific (strength/leverage, scrummaging mechanics)	—	—	—	Limits correlation because tight five success depends heavily on scrum/lineout-specific technique, leverage, binding, foot placement under strain, and collision bracing patterns not trained by high jump.	Open source
[67]	Different kinetic chain emphasis (vertical takeoff vs sustained isometric/drive and lateral collision bracing)	—	—	—	Reduces transfer further because scrummaging and repeated collision drives emphasize different force application directions (pushing/engaging) and often sustained whole-body bracing rather than vertical takeoff/landing mechanics.	Open source
[68]	Athletic transfer: explosive leg power for scrum drive and collision tolerance	N/A (modeled estimate)	2026	Internal sports science reasoning	Long/triple jump success indicates explosive lower-body power, elastic stiffness/recoil, and coordinated force application that can modestly help with the initial burst and overall physical readiness needed in scrum/close-contact work.	Open source
[69]	Sport-specific limitation: set-piece technique, bindings, and collision skill	N/A (modeled estimate)	2026	Internal sports science reasoning	Tight five performance depends heavily on rugby-specific set-piece mechanics (scrum technique, body positions, leverage, binding), close-contact law/technique, and repeated collision/ruck-area positioning—skills not trained directly by horizontal jump takeoff/landing.	Open source
[70]	Bayesian uncertainty from athlete specialization/contact background	N/A (modeled estimate)	2026	Internal sports science reasoning	Transfer varies depending on whether a jumper also has rugby exposure and strength/contact training; that changes correlation size and creates variance.	Open source
[71]	Pole vault → rugby tight five prior	Bayesian prior: explosive field-jump athleticism → rugby tight-five contact baseline (no direct empirical estimate)	2026	Internal sports-science heuristic	Sets a modest positive baseline because pole vault suggests explosive whole-body power, balance/landing control, and the ability to generate force quickly—useful for repeated drives and maintaining stability in collisions.	Open source
[72]	Rugby tight-five success depends on rugby-specific contact/set-piece skills	Motor skill specificity: set-piece/contact technique dominates	2010	Sports motor learning knowledge base	Reduces transfer: tight-five performance is dominated by scrum/lineout technical fundamentals, leverage, hand/arm positioning, body angles, ruck/maul technique, and match-specific decision-making—skills not trained by pole vault.	Open source
[73]	General explosive strength and collision readiness transfer (limited)	General force/contact readiness transfer (small)	2018	Sports biomechanics/conditioning knowledge base	Adds a small component because explosive power and proprioceptive control can help with repeated collisions and short-area driving, but it won’t overcome missing scrum technique.	Open source
[74]	General conditioning/athletic discipline transfer (limited)	N/A (transfer synthesis)	N/A	Sports science reasoning (no single primary source)	Used to justify a small positive correlation because middle-distance success indicates aerobic work capacity, movement efficiency, and training discipline—useful for maintaining performance and recovering between phases even in collision-heavy roles.	Open source
[75]	Set-piece/collision technique mismatch dominates tight five	N/A (specificity mismatch)	N/A	Sports science reasoning (no single primary source)	Applied a downward adjustment because tight five performance is heavily determined by sport-specific strength and collision/ruck/set-piece technique, body positioning and leverage in scrums/mauls, and contact tolerance—factors that are not meaningfully developed by middle-distance running technique.	Open source
[76]	Sprint/hurdle to rugby tight five transfer model (explosive movement vs set-piece collision/strength)	Internal sports-science reasoning	N/A	N/A	Estimated carry-over from sprints/hurdles success to rugby tight five roles by weighting shared components: general power expression, collision readiness, and ability to accelerate briefly out of set positions. Reduced because tight five performance is dominated by set-piece technique (scrum/lineout), binding/foot placement, wrestling and sustained force application, and repeated collision/contact skills—plus specialized strength and stabilization mechanics that sprint/hurdle training does not directly teach.	Open source
[77]	Discus rotational power and tight five collision force needs	Shared force/leverage athletic substrate (general)	N/A	Sports science reasoning (general)	Discus success reflects rotational strength, leverage use, trunk/hip sequencing, and the ability to apply high force quickly—qualities that can help tight-five players generate and transfer force in scrums/close contact and collisions.	Open source
[78]	Technical set-piece and contact mechanics are rugby-specific	Specificity principle (general)	N/A	Motor learning specificity (general)	Tight five roles depend heavily on scrum techniques, set-piece coordination, ruck/maul engagement rules, and collision timing/hand placement—skills not trained by discus throwing mechanics.	Open source
[79]	Different rugby exposure among discus athletes affects observed correlation	Selection/training confounding (general)	N/A	Participation/selection reasoning (general)	Athletes who also play rugby or other contact sports in addition to discus will show a higher correlation, while those without such exposure will show lower carry-over, widening the uncertainty.	Open source
[80]	Hammer throw → rugby tight five: force production, leverage, and balance under collision	Skill overlap mapping (internal)	2026	Internal modeling assumption	Moderate overlap expected because both reward whole-body power, kinetic-chain force transfer, and balance/control while applying force against resistance. Tight five roles also value leverage concepts and stability in contact.	Open source
[81]	Rotational throw vs scrum/ruck set-piece stability mechanics	Task/technical mismatch prior (internal)	2026	Internal modeling assumption	Correlation reduced because tight five performance is dominated by rugby-specific set-piece technique (scrummaging mechanics, body angles, binding/foot placement), repeated contact and collision timing, and ball-in-play roles (mauls/ruck entries, kicking/carry decisions) not trained by hammer throw.	Open source
[82]	Skill-transfer model intuition for javelin → rugby tight five	Internal skill-transfer reasoning (no single paper citation used)	2026	Internal reasoning	Used overlap of transferable components: explosive whole-body kinetic-chain sequencing, high-force production, shoulder/arm power (useful for grappling/contact and short clears/pass actions), and general technical practice discipline. Reduced because tight five success is dominated by rugby-specific mechanics and perceptual skills: set-piece engagement technique, repeated collision/tackling safety, scrummaging/ruck body positioning, and breakdown/ruck-specific decision-making—skills not trained by javelin’s throw-release pattern. Any purely physical-proportion advantages are ignored per instructions.	Open source
[83]	Transfer is higher when the future role shares underlying physical skills (force production, bracing, collision readiness), even if it lacks sport-specific ball/contact techniques.	General sports transfer principles	n/a	Sports science general knowledge	Set a moderate positive correlation because shot put strongly reflects force production and bracing, which tight-five roles also require.	Open source
[84]	Both shot put and scrummaging-type roles reward effective hip/trunk sequencing, leverage, and ability to apply force in short bursts with whole-body coupling.	Biomechanics/leverage reasoning	n/a	General biomechanics & motor control reasoning	Increased correlation to reflect overlap in how leverage and force are generated and transmitted.	Open source
[85]	Scrum/maul and set-piece effectiveness depends on rugby-native techniques (body positioning under laws, timing of engagement, binding/footwork patterns) and tactical coordination; these aren’t trained by shot put.	Rule/technique specificity mismatch (contact patterns + set-piece technique)	n/a	General motor learning & sport cognition reasoning	Prevented the correlation from becoming too high by accounting for rugby-specific learned mechanics.	Open source
[86]	Tight five roles vary (scrum-focused vs more mobile forward), and some shot put athletes may have prior rugby/contact sport exposure that makes adaptation faster; others will not.	Athlete self-selection and role variability	n/a	General athlete self-selection reasoning	Kept std dev fairly large to reflect scatter in transition success across tight-five substyles.	Open source
[87]	Badminton’s rally/coordination skills only partially map to tight five demands; scrummage/set-piece technique and collision mechanics limit transfer.	General transfer priors (racket sport → contact forward role)	2026	Internal sports-science reasoning	Set mean around ~0.04–0.08 because most of what matters in tight five is rugby-specific contact and set-piece technique.	—
[88]	Tight five players still need coordinated footwork, balance, and body positioning through contact; badminton can contribute general neuromuscular control and reaction.	Minor overlap: body control and footwork under pressure	2026	Internal sports-science reasoning	Adjusted slightly upward toward ~0.06–0.07.	—
[89]	Tight five success is driven by scrum technique, binding/engagement timing, leverage against opponents, ruck/maul roles, and safe repeat collision skills—none are trained in badminton.	Large reset factors: scrummaging mechanics and collision tolerance	2026	Internal sports-science reasoning	Prevented correlation from exceeding ~0.14.	—
[90]	Transfer varies depending on whether the athlete also trains strength/contact or has rugby-like background; otherwise badminton specialists may adapt more slowly.	Heterogeneity: athlete pathways	2026	Internal sports-science reasoning	Chose std dev ~0.05 to reflect meaningful variance.	—
[91]	Core skill family mismatch (catcher receiving/blocking vs tight-five scrummaging/close contact)	Authors n/a	2026	Internal sports-science reasoning	Catcher success is mostly reactive receiving/blocking and game-calling from a crouch; tight-five performance hinges on scrummaging technique, binding/engagement mechanics, set-piece stability, ruck/collision repeatability—skills not trained in baseball catcher roles.	—
[92]	Shared general athleticism (small positive)	Authors n/a	2026	Internal sports-science reasoning	Any athlete who is highly skilled at one sport often has good coordination and learning ability, which can help pick up new contact/set-piece skills faster—so the correlation is not exactly zero.	—
[93]	Tight-five likely includes non-skill factors (downweighted)	Authors n/a	2026	Internal sports-science reasoning	Even though the prompt asks to ignore body-proportion traits, rugby tight-five roles are strongly constrained by body mechanics for stability/force generation. Because those constraints tend to correlate with performance, the technique-only transfer signal is diluted, keeping the estimate very low.	—
[94]	Transfer depends on functional overlap; contact mechanics and role-specific skills constrain it	Motor learning / transfer-of-training principles (general)	N/A	Sports science / motor learning literature	Used to keep the correlation low: baseball fielding overlaps mainly in perception/coordination, but tight five requires specialized scrum/contact mechanics.	Open source
[95]	Tight five requires event-specific set-piece force production and collision technique	Rugby union scrum/close-contact biomechanics (general coaching/biomechanics knowledge)	N/A	Rugby biomechanics/coaching knowledge	Supports a low value because the key technical determinants are scrum positioning, binding, leverage, repeated collision/contact mechanics.	Open source
[96]	Decision-making and ball awareness can transfer to set-piece involvement	Perceptual-cognitive skill transfer in team sports (general)	N/A	Vision & decision-making in sport research (general)	Allows a small positive correlation because tight five still depends on reading play and maintaining coordination around set pieces, even if most technique is distinct.	Open source
[97]	Transfer estimate: baseball pitcher → rugby union tight five	Not applicable (skills-transfer estimate; no direct empirical correlation provided)	2026	Internal model	Estimated from limited overlap in transferable skills (forceful coordinated arm action, timing, repeated high-effort capability, basic hand–eye coordination for short-range ball handling/throw-ins). Explicitly discounts body-mass/strength/power-related selection effects because tight-five performance is heavily driven by set-piece force production and collision technique. Technique overlap is modest: pitching mechanics don’t teach scrum entry/engagement, binding/positioning, rucking mechanics, or repeated contact-specific movement patterns.	Open source
[98]	Basketball (Big) → Rugby union (Tight five) technique-transfer estimate	Internal domain reasoning	2026	N/A	Estimated from overlap in (1) whole-body strength/leg drive and bracing, (2) balance under physical load, and (3) basic contact tolerance/movement coordination. Downward adjusted because tight-five success depends heavily on rugby-specific set-piece technique (scrum engagement mechanics, binding, posture), repeated high-force collisions with specific body angles, and role-system knowledge; basketball Big interior play is only indirectly related. Physical-proportion advantages are excluded.	Open source
[99]	Source	Internal sports-science reasoning (no external dataset used)	N/A	N/A	Estimated very low carry-over from basketball guard to rugby union tight five based on limited shared skills (general coordination, some short-burst athleticism, basic ball skills) while heavily discounting for tight five specialization in scrum/lineout set-piece technique, collision/tackling mechanics, and close-contact force generation.	Open source
[100]	Basketball wing → Rugby union tight five transfer (technique/mentality only)	(Internal skill-overlap mapping; no single paper cited)	2026	Internal synthesis	Set a small positive baseline: basketball wings contribute general athletic coordination, footwork, and game understanding, which can help with early adaptation to being a collision player and set-piece positioning/effort.	—
[101]	Down-weighting due to tight-five-specific physical contact and set-piece technique	(Internal down-weighting for set-piece mass-force and collision mechanics; no single paper cited)	2026	Internal synthesis	Reduced because tight five success is dominated by rugby-specific set-piece mechanics (scrummaging footwork/hand placement/engagement timing), maul/lineout technique, and collision/tackling under tight constraints—skills that are not trained in basketball wing roles. Also repeated collisions and leverage mechanics are sport- and role-specific, limiting transfer.	—
[102]	Transfer of pressure handling, body positioning, and tolerance for contact	Combat sports to collision sports transfer (general)	N/A	General sports science / coaching syntheses	Supports a small positive correlation because both boxing and rugby tight-five demand learning to stay balanced and effective during physical collisions and sustained contact stress.	Open source
[103]	What drives tight-five performance: set-piece technique and collision mechanics	Rugby tight five determinants (general)	N/A	General rugby coaching references	Limits the correlation because tight-five success is dominated by rugby-specific set-piece skills (scrum/lineout laws and mechanics), ruck/maul work, ball-carrying technique, and precise tackle/entry execution.	Open source
[104]	Specificity of motor learning reduces far transfer when task mechanics differ	Motor learning specificity / far transfer limits (general)	N/A	General motor learning literature	Prevents the correlation from being too high: boxing striking/guard does not train scrum body mechanics, binding/foot placement, or set-piece timing constraints.	Open source
[105]	Bouldering-to-tight-five transfer heuristic	Internal sports-skill transfer heuristic (no direct empirical study used)	N/A	N/A	Estimated technique-only carry-over from bouldering to rugby union tight five, using overlap in general bracing/body-control, proprioception, and short-burst strength/force production. Discounted rugby-specific set-piece and collision technique and excluded non-skill physique/proportion effects (which would otherwise dominate tight-five success).	Open source
[106]	General transfer: collision-tolerant body control and technical consistency	Authors n/a	N/A	N/A	Sets a small positive baseline because lead climbing develops body control, posture under fatigue, and the habit of staying technically consistent when under physical stress.	Open source
[107]	Set-piece specificity dominates: scrum mechanics and repeated collision patterns are unique	Authors n/a	N/A	N/A	Limits carry-over because tight five success depends heavily on scrum technique (binding, leverage angles), short-range collision mechanics, and set-piece coordination that lead climbing doesn’t train.	Open source
[108]	Energy/force pattern mismatch (isometric/hold tension vs repeated scrum drives)	Authors n/a	N/A	N/A	Keeps correlation low-to-very modest because lead climbing’s force demands are often hold-based and paced, whereas scrum requires repeated explosive drive phases and different force-angle strategies.	Open source
[109]	Athlete heterogeneity in lead climbing affects how much power-oriented traits transfer	Authors n/a	N/A	N/A	Widen uncertainty: some lead climbers are more power/strength-oriented while others are endurance/route-oriented, changing transfer to close-contact roles.	Open source
[110]	Some conditioning and collision tolerance via repeated high-intensity effort	(General sports-science priors)	2026	N/A	Speed climbing develops repeated explosive effort and overall contact-readiness/fitness habits, which can modestly help with the intensity of tight-five training.	Open source
[111]	Whole-body coordination under force	(General sports-science priors)	2026	N/A	Both involve coordinated whole-body bracing and maintaining technique while generating force; this gives a small positive carry-over for set-piece body positioning.	Open source
[112]	Major mismatch: tight-five depends on scrum/set-piece technique and mass-based contact mechanics	(General sports-science priors)	2026	N/A	Tight-five effectiveness is dominated by rugby-specific set-piece mechanics (scrum engagement, binding, body angle, ruck entry/exit rules) and sustained collisions—skills climbing speed does not teach directly.	Open source
[113]	Correlation suppressed because only technique transfer is counted (but real outcomes are proportion/contact-dependent)	(General sports-science priors)	2026	N/A	Ignoring physique-based advantages reduces what would otherwise increase real-world association, keeping the expected carry-over low.	Open source
[114]	Conditioning habit transfer is limited	General sports-skill transfer knowledge	n/a	Sports science domain knowledge	Cricket all-rounders train endurance and some bursts, but tight five rugby relies on repeated intense collisions and set-piece specific conditioning that cricket doesn’t train directly.	Open source
[115]	Competitive mentality under pressure transfer (small)	General sports-skill transfer knowledge	n/a	Sports science domain knowledge	Both involve physical/competitive stress and learning to persist through fatigue, which can help adaptation, but it’s not enough for set-piece dominance.	Open source
[116]	Set-piece and collision technique is highly sport-specific	General sports-skill transfer knowledge	n/a	Sports science domain knowledge	Tight five success is dominated by rugby-specific scrum/lineout technique: binding, body position, driving mechanics, and breakdown rules—skills not developed in cricket.	Open source
[117]	Mass/force/contact demands are major predictors (excluded)	General sports-skill transfer knowledge	n/a	Sports science domain knowledge	Tight five roles strongly depend on mass, leverage, and contact force tolerance. Since the estimate must disregard body-proportional advantages, the remaining technique/learning overlap becomes very small.	Open source
[118]	Overlap in ball-handling/kicking is minimal	General sports-skill transfer knowledge	n/a	Sports science domain knowledge	Cricket all-rounding includes batting/bowling skill and open-field fielding; tight five plays heavily in set-piece collisions and short-range ball phases, so cricket skill overlap is limited.	Open source
[119]	Skill-overlap reasoning between cricket batter mechanics and rugby tight five contact/set-piece roles	Assumed from sports-skill overlap heuristics (no single study cited)	2026	Internal sports science synthesis	Used a near-zero positive correlation because the overlapping transferable skills are mainly general coordination/balance, while tight five success depends heavily on rugby-specific set-piece technique, body positioning, collision/tackling mechanics, and repeated scrum/lineout work that cricket batting does not train.	Open source
[120]	Core learned motor programs differ strongly	Technique mismatch (throw vs scrum contact)	N/A	Sports science knowledge (no single citation)	Cricket bowling success is driven by overarm delivery mechanics and ball-release sequencing. Rugby tight five success is dominated by set-piece body positioning, scrummaging technique, and repeated close-contact force application—different motor patterns.	Open source
[121]	General hard-effort/pressure tolerance transfers modestly	Shared athletic contact tolerance as general factor	N/A	Sports science knowledge (no single citation)	Both roles require repeated intense efforts and staying coordinated under physical pressure; this can create a small positive correlation at the conditioning/mental level.	Open source
[122]	Prior sport expertise predicts faster adaptation	Learning/adaptation and practice habits	N/A	General evidence base (no single citation)	Good specialists often learn new complex technical systems faster and train with better structure, adding a modest extra tail.	Open source
[123]	Set-piece and collision mechanics dominate outcomes	Tight-five determinants are rugby-specific	N/A	Coaching/sport science summaries (no single citation)	Tight five performance depends on scrum/lineout timing, binding/engagement mechanics, leverage, and repeated collision tactics not trained in cricket bowling, limiting transfer.	Open source
[124]	Cross-training background varies widely across bowlers	Large between-athlete variability	N/A	Methodological heuristic (no single citation)	Some bowlers may have strong collision/running backgrounds, others not; this increases uncertainty (std dev).	Open source
[125]	Transfer priors: basic athleticism, contact readiness (limited)	—	—	General sports science knowledge	Wicketkeeping can correlate weakly with rugby forward aptitude via general coordination, balance, and ability to perform repeatedly under match conditions.	—
[126]	Mismatch: wicketkeeping is not set-piece collision/force production training	—	—	General coaching principles	Tight five success is heavily driven by scrum/maul technique, set-piece biomechanics, strength-to-mass force production, and collision/tackle mechanics—skills wicketkeeping does not train directly.	—
[127]	Demand mismatch: handling/kicking differences	—	—	General training principles	Rugby tight five roles rely on specific rugby ball handling, ruck/maul roles, and kicking in limited ways, which differ from wicketkeeping’s glove receiving/throwing.	—
[128]	Low overlap in rule-constrained movement patterns	—	—	General training considerations	Wicketkeeping’s movement pattern (reactive receiving from a low stance) doesn’t match the repeated forceful, coordinated collision and set-piece positioning patterns of tight five play.	—
[129]	MTB cross-country → rugby tight five transfer heuristic (general endurance/coordination vs missing scrummaging/engagement force + set-piece technique)	Authors n/a	2026	Internal reasoning	Estimated low positive correlation because both can involve repeated physical contests and general conditioning, but tight five success depends heavily on sport-specific set-piece and collision/engagement mechanics (scrum technique, body positioning, binding/hand use) and very short maximal-force power that MTB cross-country does not train directly (especially technique).	Open source
[130]	Cycling road climber → Rugby union tight five transfer heuristic	No direct empirical meta-analysis used; Bayesian heuristic based on endurance/work-capacity transfer from road-climber cycling to rugby tight-five conditioning demands.	2026	Internal sports science synthesis	Assigned a small positive correlation: shared demands for repeat-effort, conditioning, and general collision-exposure trainability. Discounted heavier because tight-five success depends heavily on rugby-specific strength/power, scrummaging technique, set-piece body positioning, collision-specific motor patterns, and contact/tackling skill development that cycling climbing does not teach directly; also open-field running/ball skills are less central than for other rugby roles.	—
[131]	Cross-sport transfer heuristics (cycling sprinter → rugby tight five)	Authors n/a	2026	Internal reasoning	Cycling sprinter success implies high power output, ability to repeat hard efforts, and high training discipline—helpful for the physical workload of scrums/close-contact phases and repeated collision tolerance. However tight-five effectiveness is dominated by scrum technique, leverage, and collision-specific mechanics.	—
[132]	Technique specificity / limited overlap in contact mechanics	Authors n/a	2026	Internal reasoning	Tight five performance depends strongly on rugby-specific set-piece technique (binding, body angle/leverage, foot placement, sequencing in scrum) and close-contact collision/ruck technique, which cycling does not train. This caps predictive carryover.	—
[133]	Conditioning overlap (power + repeated high-intensity)	Authors n/a	2026	Internal reasoning	While cycling pedaling mechanics are different, the underlying conditioning (anaerobic power, ability to work hard for short bursts, and recovery between intense phases) overlaps partially with forward roles.	—
[134]	Transfer heuristic: endurance cycling → scrum/close-contact work capacity (indirect)	Authors n/a	N/A	N/A	Set a modest base correlation because time-trial cycling builds aerobic engine, repeated-effort tolerance, and training discipline that can help tight five players sustain match work, recover between set-pieces, and progress in strength/power training.	—
[135]	Bayesian adjustment: low technique overlap for set-piece/collision skills	Authors n/a	N/A	N/A	Reduced correlation because tight five performance is dominated by rugby-specific technical/tactical set-piece mechanics (scrum technique, body positioning) and collision/tackle/ruck actions—skills not trained by road time-trial cycling. Any carry-over is mostly indirect and variable.	—
[136]	Specificity dominates when primary determinants differ	Determinant mismatch (endurance cycling vs set-piece collision)	N/A	N/A	Endurance track cycling success is driven by sustained power/pace and repeat-effort pacing, while tight five (scrum/close-contact) success depends heavily on set-piece stability, force production in short collisions, and collision mechanics. Limited overlap in primary technique determinants keeps correlation low.	Open source
[137]	Attention/decision-making transfer is weak across very different movement patterns	Perceptual-cognitive carryover (tactical awareness)	N/A	N/A	Cycling can help with tactical scanning and game awareness, which can slightly support set-piece decision-making and positioning, but it cannot substitute for tight-five contact/set-piece technique.	Open source
[138]	Endurance supports repeated collisions and training volume	Work capacity supporting repeated physical phases (general)	N/A	N/A	Even though the movement pattern differs, endurance conditioning can help maintain effort quality through many phases and tolerate high training volume for scrummaging/contacts, giving a small positive effect.	Open source
[139]	Efficient technical learning habits	Learning discipline and self-coaching (general)	N/A	N/A	High-level cycling athletes often show structured training habits and ability to refine technique efficiently, modestly aiding the transition to set-piece mechanics.	Open source
[140]	Source synthesized from general transfer principles; no single direct study located for this exact pairing	Internal sports-science reasoning (limited transfer from sprint cycling to scrum/collision set-piece roles)	N/A	N/A	Used to estimate carry-over from track sprint cycling to rugby tight five set-piece collision roles. Accounted for some shared capacity for repeated high-intensity effort and general force production, but discounted heavily because tight five success relies on scrum mechanics, body positioning, contact/tackling technique in prolonged collisions, and set-piece-specific power/skills not trained by velodrome sprint cycling.	Open source
[141]	Epee success reflects timing, distance/angle judgment, and reactive footwork/positioning	Fencing performance determinants (general)	N/A	General sports science / fencing coaching literature	Supports only a small potential transfer via general balance/coordination and tactical timing relevant to contact decisions.	Open source
[142]	Tight five success depends on set-piece technique, leverage/force, body positioning in scrums, and collision skills	Rugby tight five determinants (general)	N/A	General rugby coaching/sports science literature	Explains why carry-over should be low: tight five performance is dominated by rugby-specific force-leverage mechanics and set-piece/collision techniques not trained in epee.	Open source
[143]	Transfer is limited when tool mechanics and primary performance constraints differ substantially	Skill transfer across sports (general)	N/A	General motor learning / sports psychology research	Justifies keeping correlation near the low end because epee’s combat distance/point-timing differs from scrum/close-contact force production and rules.	Open source
[144]	Transfer of training (conceptual)	Transfer of training (decision/timing under pressure)	n.d.	General sports science literature (no single source)	Foil can help with general fight-composure and timing of actions in contact-heavy moments, giving a small positive carryover.	Open source
[145]	Perception–action overlap is modest when primary mechanics differ (conceptual)	Perceptual anticipation overlap limited	n.d.	General perceptual-motor / sport psychology synthesis (no single source)	Rugby tight-five roles do involve reading engagements, but the dominant determinants are set-piece collision mechanics rather than opponent-timing only.	Open source
[146]	Task specificity limits cross-sport prediction (conceptual)	Mechanics/rule mismatch: non-contact fencing vs scrummaging/tackling	n.d.	General motor learning / biomechanics principles (no single source)	Tight-five performance depends on scrum stability, leverage, collision technique, repeated high-force contacts, and set-piece coordination—mechanics not trained by foil’s lunge/point-control and non-contact interaction.	Open source
[147]	Estimated skill carry-over from fencing sabre to rugby union tight five (scrum/close-contact)	Unnamed (model-based synthesis)	2026	Internal sports-science reasoning	Used to estimate a very low positive correlation from general athletic/coordination traits shared by both: explosive initiation and decision-making under pressure. Discounted strongly because tight five success depends on rugby-specific set-piece stability, binding/engagement technique, collision mechanics, driving/leg power transfer, and repeated scrum/maul roles not trained in sabre fencing; excluded body-size effects per prompt.	Open source
[148]	Transfer of learning: general defensive awareness and collision readiness transfer less across very different role mechanics	Transfer of learning (generalized)	—	—	Used to justify a small positive correlation from general skills (alertness, body control, learning under pressure) even when core techniques differ strongly.	Open source
[149]	Field hockey goalkeeping: reactive positioning and stance control under pressure	Field hockey goalkeeper demands (generalized)	—	—	Used to identify the transferable component: staying composed and balanced while reacting to fast, close-range threats.	Open source
[150]	Rugby tight five: set-piece stability, scrummaging and close-contact collisions	Rugby union tight five demands (generalized)	—	—	Used to constrain transfer because tight-five success depends heavily on rugby-specific contact mechanics (scrummaging technique, collision/bracing, legality/timing) that hockey goalkeeping does not train.	Open source
[151]	Field hockey outfield → rugby union tight five: limited because of dominant set-piece/contact mechanics mismatch	Structured cross-sport transfer reasoning (not a single study)	2026	Internal sports science reasoning	Estimated low carry-over from shared attributes like field awareness, repeated bursts of effort, and basic contact readiness. Reduced because tight five performance is dominated by rugby-specific set-piece mechanics (scrummaging technique, binding/engagement positions), repeated collision timing, driving force production in structured phases, and specialized body positioning—skills hockey outfield only partially develops.	Open source
[152]	Invasion stick sport to set-piece collision forward roles	General transfer-principle priors (contact specificity; far transfer)	2026	Internal sports science reasoning	Used a conservative prior because technique determinants differ strongly: hockey’s stick/field roles vs rugby’s scrum/lineout contact and driving mechanics. Rugby tight five overlap is more about physical/contact technique than the hockey skill core.	Open source
[153]	Across substantially different sports, correlations are small because shared predictors are mostly general motor learning and competitive self-regulation	General sports skill transfer / far-transfer synthesis	~2010s-2020s	Peer-reviewed sports science (general synthesis)	Baseline for golf → rugby tight five given minimal technique overlap (precision striking vs scrum/close-contact mechanics).	Open source
[154]	Reactive decision-making, body control, and learning complex technique can transfer weakly to new contact sports	Collision-sport technical and perceptual adaptation (general)	~2000s-2020s	Motor learning / perceptual-cognitive research (general synthesis)	Justifies a small positive value because tight-five roles still rely on learning set-piece and contact techniques efficiently, where golf may correlate via general technique-learning habits and composure.	Open source
[155]	Transfer of body control, balance recovery, and force control across sports (motor learning framework)	Motor learning / coordination and bracing transfer (general)	various	Sports science / motor learning literature	Sets a small baseline positive carryover because gymnastics builds trunk bracing, controlled force application, and body positioning—useful for set-piece stability and collision mechanics even if the sport is different.	Open source
[156]	Effects of high-control strength and impact/landing mechanics on collision stabilization (representative)	Strength and isometric control from gymnastics (representative)	various	Strength & conditioning / biomechanics practice knowledge	Adds slight correlation since tight five play involves repeated collision stabilization where core stiffness/landing-control habits can help.	Open source
[157]	Tight-five performance depends strongly on rugby-specific set-piece technique and collision rules	Rugby tight-five specificity mismatch	various	Coaching/performance practice knowledge	Keeps correlation low because success is dominated by rugby-specific scrum/lineout technique, binding/hand position rules, driving mechanics, and repeated contact/ruck-leg laws that gymnastics doesn’t train directly.	Open source
[158]	Rhythmic gymnastics prerequisites for tight-five movement quality	General body control, balance, and landing mechanics (conceptual)	N/A	Internal reasoning	Rhythmic improves balance, proprioception, and whole-body control that can help with stable body positions and repeatable footwork during collisions.	Open source
[159]	Body-line control relevant to scrum posture and contact stability	Technique/position control in contact context (partial)	N/A	Internal reasoning	Apparatus work can support better posture control and coordination in complex body positions, which may help with initial scrum/collision technique learning (movement-quality side).	Open source
[160]	Why tight-five success depends on scrum/rucket-specific skill and maximal collisions	Rugby-specific force production and set-piece technique limitation	N/A	Internal reasoning	Tight-five performance is dominated by rugby-specific set-piece mechanics (scrum engagement/posture, binding), collision bracing, repeated high-force impact tolerance, and legal ruck/maul technique—training not provided by rhythmic apparatus routines.	Open source
[161]	Variance from prior rugby/strength/contact exposure	Athlete background variance	N/A	Internal reasoning	Kept uncertainty moderate-high: transfer is larger for athletes with rugby/strength/contact background and smaller otherwise.	Open source
[162]	Trampoline improves balance and coordination for collisions	General neuromotor transfer (Bayesian heuristic)	2026	Internal heuristic synthesis	Baseline small positive correlation: trampoline builds proprioception and posture control that can help athletes stay coordinated during repeated impacts (technique-only).	Open source
[163]	Tight five success depends on scrum/collision mechanics and leverage	Contact/collision technique specificity gap (Bayesian heuristic)	2026	Internal heuristic synthesis	Capped carryover because tight five performance is dominated by scrum technique, set-piece body positioning, leverage, and collision/engagement mechanics not trained in trampoline.	Open source
[164]	Repeated collisions are different stimulus than elastic aerial control	Role-specific repeated contact loading mismatch (Bayesian heuristic)	2026	Internal heuristic synthesis	Adjusted downward: trampoline does not replicate the neuromechanical pattern of sustained engagement and repeated scrummaging contacts.	Open source
[165]	Excludes body-proportion effects typical for tight five	Trait confounds filtered out (constraint)	2026	Internal heuristic synthesis	Kept mean very low since many tight-five advantages come from mass/leverage; with those excluded, only limited technique/coordination transfer remains.	Open source
[166]	Skill-overlap heuristic: Handball (backcourt) → Rugby union (tight five)	Internal sports-science rationale (Bayesian skill-overlap heuristic)	N/A	N/A	Estimated carry-over from shared general athletic capabilities (upper-body strength/coordination, body positioning, short bursts, and basic handling/decision-making) while heavily discounting rugby tight-five specifics: scrum/lineout set-piece techniques, binding/leg-drive mechanics, repetitive collision/contact tolerance and tackle/ruck body mechanics, plus sustained role-specific conditioning.	Open source
[167]	Transfer-principles: limited carryover when contact/set-piece technique dominates	General sports transfer principles (perception/athleticism vs sport-specific contact technique)	N/A	Synthesis	Sets a low prior because handball goalkeeper skill is mainly reactive shot-stopping/positioning, while tight five success is driven by rugby-specific scrummaging/lean technique and collision mechanics.	Open source
[168]	Handball goalkeeper: rapid coordination and contact readiness	Handball goalkeeper demands (reactive movement and whole-body coordination)	N/A	Synthesis	Supports a small positive adjustment: elite goalkeepers often have good whole-body coordination, balance, and ability to absorb/manage force and chaos, which can help in learning contact roles.	Open source
[169]	Tight five: scrummaging force, stability, and collision technique	Tight five demands (scrummaging stability, repeated collisions, force application)	N/A	Synthesis	Drives correlation down: tight five performance depends heavily on rugby set-piece mechanics (body positions, engagement timing, leverage in scrum) and collision/ruck technique that are not trained in handball goalkeeping.	Open source
[170]	Skill-carryover mapping: handball pivot → rugby union tight five	{Bayesian estimate based on transferable technique/skill domains: contact balance, collision tolerance, maintaining posture in scrum-like congestion, and decision-making under physical pressure from handball pivot to rugby tight five; excluding body-mass/height/strength advantage per instructions}	2026	Internal sports science reasoning	Used to estimate overlap from pivot’s tight-space battling skills (balance, posture control under contact, keeping leverage/position, quick reaction in congested play) to rugby tight five demands (scrum/close-contact stability, repeated collisions, body positioning and set-piece physicality), while discounting the biggest rugby-specific technical elements (scrum technique specifics, binding rules, lineout/ruck detail) and excluding any physique/mass effect.	Open source
[171]	Skill-transfer heuristic: handball wing → rugby union tight five	(Model estimate)	2026	Internal sports science reasoning	Bayesian baseline based on limited transferable athletic qualities (explosive leg power, agility in short bursts, general ball skills and spatial awareness) while heavily discounting tight-five-dominant technical/contact requirements (scrum mechanics/engagement, maul/lineout set-piece skills, ruck collision law execution, specific tackling/leverage patterns).	Open source
[172]	Shared contact/collision demands create modest transfer even when rules/ball skills differ	General inter-sport transfer principles	N/A	Sports science knowledge synthesis	Used to set a modest positive baseline because both hockey defense and rugby tight five involve frequent high-force collisions, body positioning, and repeatable bracing under contact.	Open source
[173]	Contested-contact and set-piece stability analogs	Ice hockey defenseman → rugby tight five overlap (domain reasoning)	N/A	Coaching/sports science domain knowledge	Adjusted upward: defensemen practice shielding space, sustaining contact tolerance, and surviving repeated physical contests—qualities useful for scrum/close-contact roles where stability and force application matter.	Open source
[174]	Scrum/ruck/maul mechanics limit cross-prediction	Rugby set-piece technique specificity	N/A	Sports science knowledge synthesis	Reduced correlation because tight five performance depends heavily on rugby-specific techniques (scrummaging mechanics, legal binding/angles, repeated ruck-entry positioning) which hockey does not train.	Open source
[175]	Different defensemen emphasize different skill mixes	Role variability and skill composition	N/A	Coaching/sports science knowledge synthesis	Kept standard deviation fairly large: some defensemen are more physically-contested and adapt better; others are more skating/shot-block oriented, transferring less to set-piece stability demands.	Open source
[176]	Ice hockey forward → rugby tight five: partial transfer via collision experience + whole-body power	(Expert judgment; Bayesian prior on collision contact tolerance + power)	2026	Internal reasoning	Used a modest positive prior because hockey forwards repeatedly experience contact, play through physical pressure, and develop strength/power and body positioning skills relevant to scrum/close-contact roles.	Open source
[177]	Tight five technique/role specificity: scrum mechanics and set-piece timing	(Expert judgment; technique specificity discount)	2026	Internal reasoning	Discounted because tight five performance is dominated by rugby-specific technique: scrum binding and body angles, ruck/maul footwork, tackling/leverage rules, and set-piece coordination; hockey’s puck-and-skating technique doesn’t directly train these.	Open source
[178]	General contact readiness + positioning under pressure	N/A	N/A	Internal sports science reasoning (no single primary paper cited)	Slightly increases correlation: goalkeepers learn to hold position under physical disturbance, maintain balance, and execute explosive movements repeatedly in high-pressure contact-like situations.	Open source
[179]	Lower overall overlap because tight-five success is set-piece/strength-technique heavy	N/A	N/A	Internal synthesis	Reduces correlation: tight five roles depend on scrum/maul technique, binding/engagement mechanics, shoulder/arm angles, and set-piece coordination—skills not meaningfully present in goalie play.	Open source
[180]	Body contact mechanics differ substantially (collision patterns and legal techniques)	N/A	N/A	Internal synthesis	Reduces further: rugby’s collisions, tackling legality, and repeated collision tolerance are biomechanically and skill-wise distinct from net-front coverage and stick/board interactions.	Open source
[181]	High variance due to athletic profile (some goalies transition better to forward roles)	N/A	N/A	Internal synthesis	Keeps std dev fairly high: a goalie who is also heavy on skating-power, strength training, and collision readiness may transfer better; others remain specialized to reflex/coverage rather than contact mechanics.	Open source
[182]	Combat-sport contact mechanics → scrum/close-contact stability and collision tolerance	General sports-science reasoning (no single study claimed)	—	—	Used to justify a small positive baseline because judo builds posture control, leverage, and handling resistance/pressure—useful for tight-five demands like scrummaging stability and repeated collisions.	Open source
[183]	Rugby set-piece technique and body position are rule-specific and not trained directly in judo	General knowledge: rugby tight-five success is highly set-piece and role-specific	—	—	Kept correlation modest and increased uncertainty because scrum technique, binding, legal body angles, collision technique, and set-piece execution are highly rugby-specific beyond judo’s clinch/grip/throw patterns.	Open source
[184]	Contact/strength-role transfer estimate: lacrosse attacker → rugby tight five	Authors n/a	2026	Internal reasoning	Estimated carry-over via shared collision/contact experience, physical courage, and ability to operate in traffic while staying coordinated (timing/footwork during contact) from lacrosse attacker to tight-fives’ repeated close-contact involvement.	—
[185]	Major mismatch discount: set-piece and mass/force technique vs field offense	Authors n/a	2026	Internal reasoning	Reduced because tight five performance is heavily driven by rugby-specific set-piece technique (scrum mechanics, binding/leg drive patterns), ruck/maul legal contact body positions, and specialized collision technique—skills lacrosse attackers do not train in the same way.	—
[186]	Small upward adjustment for repeated collision tolerance but not proportions (as instructed)	Authors n/a	2026	Internal reasoning	Added a small amount because you’re still transferring learned comfort with contact and sustaining repeated collisions; explicitly kept modest since physique/mass leverage effects are not being counted.	—
[187]	Lacrosse defender -> rugby tight five transfer prior	General cross-sport transfer prior (Bayesian)	2026	Internal reasoning	Set a moderate prior because both roles involve frequent physical collisions, leverage/positioning, and maintaining effectiveness while contested; however tight-five success is heavily influenced by rugby set-piece mechanics and technical scrummaging.	Open source
[188]	Lacrosse defender fundamentals relevant to tight-five transfer	Lacrosse defender skill components	2026	Coaching/technical consensus (general)	Used to identify transferable pieces: body-position/leverage habits, staying balanced through contact, reading pressure/space, and repetitive collision tolerance (technique/skill related), but noted stick/defensive checking is sport-specific.	Open source
[189]	Rugby tight five skill components	Rugby tight five requirements	2026	Coaching/technical consensus (general)	Mapped dominant requirements: set-piece scrummaging technique, ruck/maul contact skills, close-range ball handling, and repeated collision timing with rugby-specific laws—only partially overlapping with lacrosse defending.	Open source
[190]	Lacrosse goalkeeper → rugby union tight five transfer estimate	Internal sports-science reasoning (no external citations provided)	N/A	N/A	Estimated very low positive carry-over based on overlap in general athletic coordination, decision-making under pressure, and basic catching/ball awareness. Discounted strongly because tight five success is dominated by rugby-specific set-piece technique, force application, scrum mechanics, and collision/ruck body positioning—skills not trained in lacrosse goalkeeping.	Open source
[191]	Cross-sport skill/mentality carry-over estimate: lacrosse midfielder → rugby union tight five	Internal sports-science reasoning (no direct single-study source used)	N/A	N/A	Estimated from overlap in contact readiness and general collision exposure plus whole-body coordination from lacrosse midfield. Discounted for rugby tight five requiring very specific set-piece and collision technique (scrum engagement mechanics, lineout work, ruck/maul legality, binding, body positioning) that lacrosse midfield does not teach; also not using physical-morphology advantages per instruction.	Open source
[192]	Bayesian transfer priors: padel coordination/decisioning → limited relevance to tight-five set-piece collision/force roles; discounting body-mass/contact tolerance factors per specification	N/A	2026	Internal sports-science reasoning	No direct empirical correlation for Padel→Rugby union (Tight five). Estimated very low carryover because rugby tight-five success is dominated by set-piece technique (scrummaging), strength/force production, collision mechanics, and repeated contact patterns. Padel shares some general coordination and reaction skills, but does not train scrummaging/ruck/maul contact mechanics in a comparable way.	Open source
[193]	Transfer estimate: pickleball → rugby union tight five (scrum/close-contact forward roles).	Internal sports-science reasoning / domain heuristics (no direct empirical dataset provided).	N/A	N/A	Estimated near-low carry-over because pickleball’s core skills (reactive rally play, paddle/ball timing, lateral agility) overlap only weakly with tight-five demands that are dominated by scrum/ruck technique, collision mechanics, set-piece coordination, and repeated contact stability—skills that pickleball does not train directly. Any positive effect comes mainly from general athletic coordination and learning ability.	Open source
[194]	Transfer reasoning (rowing lightweight → rugby tight five): whole-body leverage/force transfer and collision conditioning habits vs non-overlap in scrum technique and set-piece timing	Internal synthesis: lightweight rowing → rugby tight five	2026	Internal synthesis	Used overlap in general athletic mechanics: whole-body coordination, leverage/force transmission concepts, repeated high-load training tolerance, and posture/stability under fatigue. Down-weighted because tight five success is dominated by rugby-specific set-piece mechanics (scrum binding/angles, ruck entry rules), collision technique, short explosive power bursts, and sport-specific strength/power and contact timing that rowing does not directly train.	—
[195]	Rowing openweight to collision sports share strength endurance and power repetition	Non-specified (shared force + collision conditioning)	n/a	Sports science consensus	Supports a higher correlation than many other sports because tight-five roles repeatedly collide and need repeated whole-body force with sustained quality; openweight rowing strongly builds whole-body strength, power, and endurance.	Open source
[196]	Scrum/tight-five technique is highly event-specific	Non-specified (technique specificity: scrum/set-piece mechanics)	n/a	Sports science consensus	Caps correlation because rowing doesn’t teach scrum binding/leg-drive coordination, set-piece rules, rucking mechanics, and exact low-body positioning under scrum loads.	Open source
[197]	General coordination and body control help learning contact mechanics	Non-specified (coordination under contact)	n/a	Biomechanics/motor learning consensus	Adds a positive component: rowing develops coordinated movement and posture control that can help a player learn safe, repeatable collision/engagement mechanics.	Open source
[198]	Shared rugby contact skill base (collisions, balance, ruck/scrum-related body control)	Authors n/a	n/a	Sports science transfer synthesis (no single canonical citation)	Halfback/midfield and tight five both operate under heavy contact and congestion, requiring balance, body positioning, and repeated high-intensity collisions—so a substantial portion of transferable rugby contact skill exists.	—
[199]	Set-piece specificity mismatch (distribution/phase play vs scrum/collision mechanics)	Authors n/a	n/a	Coaching-position-demand synthesis (no single canonical citation)	Tight five performance is driven heavily by scrum mechanics, set-piece stability, and specific close-contact engagement techniques, which are less central for halfback/midfield roles.	—
[200]	Role emphasis difference inside the same sport (playmaking vs power/engagement)	Authors n/a	n/a	Task-structure mismatch synthesis (no single canonical citation)	Halfbacks are often evaluated on distribution, kicks, and speed/decision timing, while the tight five are evaluated more on physical contest outcomes in set pieces; that caps the correlation below near-perfect.	—
[201]	Conversion variance within rugby between back and forward roles	Authors n/a	n/a	Bayesian conversion variance prior (no single canonical citation)	Even within rugby, athletes vary a lot in how quickly they can convert between backline skills and forward set-piece/collision techniques, producing a wide spread and reducing the mean from very high to moderately high.	—
[202]	Rugby union (loose forward) → Rugby union (tight five) overlap assessment	N/A (model-based estimation)	2026	Internal sports science reasoning (no single external source used)	Estimated within-sport technique carry-over because both are rugby union forward roles with overlap in contact competence, collision tolerance, body-position/leverage in contact, set-piece/phase understanding, and repeated high-effort involvement. Discounted from a perfect score due to role-specific emphasis differences: loose forward success is often driven by ruck/tackle volume, mobility, and open-field carries; tight five outcomes are dominated by set-piece stability, scrum/lineout mechanics, repeated short-range collision patterns with different force vectors, and role-specific technical compliance (bind/foot placement, scrum posture).	Open source
[203]	Same sport transfer: shared rugby decision-making and ball-in-play skills	—	N/A	Sports science synthesis	Both roles are in rugby union, so much of the underlying learning (game understanding, ball-handling under pressure, contest mindset) transfers.	Open source
[204]	Contact/collision exposure and engagement tolerance	—	N/A	Sports science synthesis	Outside backs and tight five players both experience frequent physical engagement; general tolerance and ability to operate under contact pressure should correlate positively.	Open source
[205]	Body control under collisions and repeated confrontations	—	N/A	Sports science synthesis	Outside backs need balance and body control when tackled; tight five needs stability and control in scrums and repeated contact. Some of the dynamic control habits carry over.	Open source
[206]	Set-piece/technical mismatch: scrum mechanics and force application in specific contexts	—	N/A	Sports science synthesis	Tight five performance depends heavily on scrum-specific technique (binds, body angles, coordinated pushing mechanics, set-piece stability) that outside backs rarely train.	Open source
[207]	Role-specific conditioning and workload differences	—	N/A	Sports science synthesis	Tight five involves repeated short, high-force collisions and sustained set-piece work; outside backs’ primary differentiator is open-field speed/evasion, reducing overlap in performance drivers.	Open source
[208]	Collision-tolerance and body control transfer (general)	Reasoned synthesis (no single dataset assumed)	2026	Sports science reasoning	Downhill skiing teaches force absorption, bracing, and re-centering under high impacts, which can provide a small movement-learning head start for scrum-style close-contact roles.	Open source
[209]	Set-piece/technique mismatch (scrum mechanics)	Reasoned synthesis (no single dataset assumed)	2026	Transfer-learning reasoning	Tight five success depends heavily on rugby-specific set-piece technique, leverage, body positioning, and repeated collision timing/skills in scrums/mauls—constraints not trained by alpine speed-event skiing.	Open source
[210]	Tactical structure mismatch (fixed course vs opponent-driven phases)	Reasoned synthesis (no single dataset assumed)	2026	Cognitive/temporal reasoning	Skiing is continuous control on a fixed course; rugby tight-five work is discrete set-piece execution with opponent-driven engagement, reducing transferable decision/timing mechanics.	Open source
[211]	Structured domain knowledge on skill/transfer (technique & perception) vs. traits (height/build)	—	2026	Internal sports science heuristic	Used to estimate plausibly low cross-sport correlation when technique overlap is limited and role demands in the future sport emphasize different skill sets (especially contact/set-piece work).	Open source
[212]	Sports transfer-of-training heuristic (no specific single study cited)	Authors n/a	N/A	General sports science / motor learning knowledge	Estimated low overlap: cross-country skiing (endurance/efficient whole-body coordination) vs rugby tight five (scrum/set-piece force production, collision bracing, technique-specific contact and body positioning). Shared components mainly general conditioning and coordination; most determinants in tight five are sport-specific contact/set-piece mechanics.	Open source
[213]	Cross-sport skill transfer heuristic (dynamic balance/contact readiness -> close-contact set-piece stability)	Sports science reasoning (transfer/overlap heuristic)	2026	Internal model	Estimated correlation by allowing only minimal transferable skill from snowboarding to rugby tight five: general body control, balance during forceful motion, and some collision readiness/coordination. Heavily discounted tight-five-specific technique (scrummaging body positions, binding, engagement mechanics, driving/lever sequencing) and rugby contact/tackle biomechanics that snowboarding does not train.	—
[214]	Soccer central defender: defensive positioning, aerial duels, and handling physical contests	Unknown (expert synthesis)	2026	Internal reasoning / domain expert synthesis	Supports transfer through contest skills: positioning, reading threats, and performing under collision/contact.	Open source
[215]	Rugby tight five: scrum/set-piece stability, mass collision tolerance, and repeated close-contact work	Unknown (expert synthesis)	2026	Internal reasoning / domain expert synthesis	Anchors what tight-five roles depend on (close-contact stability and collision tolerance), which overlaps partly with central defense.	Open source
[216]	Transfer is limited by sport-specific contact mechanics and set-piece technique	Unknown (expert synthesis)	2026	Internal reasoning / domain expert synthesis	Keeps correlation moderate because scrum/set-piece mechanics and rugby-ball handling are not learned in soccer defending.	Open source
[217]	Generated estimate from sports-skill overlap heuristics (no single empirical study used)	Authors n/a	2026	Internal reasoning	Transfer reasoning from soccer central midfielder to rugby union tight five. Counted overlap in: general collision readiness/dueling mindset, repeated high-effort work, spatial awareness in congested areas, and basic tackling/contestation awareness. Discounted for tight five because much of performance depends on rugby-specific set-piece and close-contact technique: scrum mechanics/positions, lineout contact and entry/role execution, ruck protection/counter-ruck behaviors, and highly sport/rules-dependent collision biomechanics and force application patterns not trained in soccer midfield.	—
[218]	Reading phases and staying composed under pressure transfers across contact field sports	Perceptual-cognitive transfer in contact sports (general)	N/A	General motor learning & sport science consensus	Used to justify a small positive correlation because both soccer goalkeeper and rugby tight-five roles involve making rapid decisions and operating reliably when play gets chaotic.	Open source
[219]	Technical/tactical dominance differs strongly between positions	Role/skill mismatch: GK vs tight-five contact/set-piece skill set (general)	N/A	General coaching/position analysis knowledge	Prevents the correlation from becoming moderate/high: tight-five performance is driven by scrum mechanics, ruck/maul contact technique, and set-piece stability—skills not present in goalkeeper play.	Open source
[220]	Learning under collisions varies greatly across individuals	Contact learning variability (general)	N/A	General collision-sport adaptation understanding	Increases expected standard deviation since some athletes adapt quickly to sustained contact technique demands, while others do poorly.	Open source
[221]	Soccer striker to rugby union tight five: low transfer via general power and contact tolerance	General sports-transfer reasoning (no single study)	2026	Internal model	Estimated low positive carry-over because soccer striker success can reflect general attributes like explosiveness, coordination, and willingness to work hard under pressure. However, tight five (scrum/close-contact) success is dominated by rugby-specific strength, set-piece technique, and repeated collision/tackling mechanics that soccer striker play doesn’t train.	—
[222]	Force production and body positioning transfer to contact roles	General perceptual-motor and force-application principles	2026	Internal model	Provided a small uplift for whole-body force production and body positioning, but heavily discounted due to the specialized scrum technique and collision mechanics of tight five.	—
[223]	Skill transfer estimate: soccer winger → rugby union tight five	N/A (inferred from sport/role overlap)	2026	AI sports-science synthesis	Estimated limited positive transfer from shared general athletic qualities (burst speed, agility, repeated effort, and some physical competitiveness). Discounted heavily because tight five (scrum/close-contact) success is dominated by rugby-specific skills: set-piece technique and coordination, binding/hand placement, scrum footwork/timing, collision-specific contact mechanics, and repeated ruck/breakdown roles that are not taught in winger soccer.	Open source
[224]	Softball catcher → rugby union tight five estimated carry-over	Heuristic sports-transfer model (general coordination/learning + low ready defensive mindset; minimal contact-technique overlap)	2026	Internal synthesis	Estimated near-zero because catcher technique (pitch reception/blocking in a crouch, ball-tracking) overlaps only weakly with tight five determinants (set-piece scrum/lineout mechanics, body positioning for collisions, binding/lever systems, repeated short contact sequences). Shared elements are mainly general athletic learning discipline and basic reactive balance, which contribute little to variance.	—
[225]	Baseline prior: softball field-player → rugby tight five (skills-only)	Unknown (modeled estimate)	2026	Internal sports-science prior	Start modest because softball fielding shares general athletic coordination and reaction, but tight-five success is heavily shaped by rugby contact, set-piece, and role-specific techniques.	—
[226]	Positive contributors: handling ball skills, agility, and contact tolerance (indirect)	Unknown (modeled estimate)	2026	Internal sports-science prior	Field players can have good ball-tracking/handling and willingness to contest space, which can help early adaptation to carrying, catching, and general contact readiness.	—
[227]	Mismatch factor: scrum/maul technique, rucking mechanics, and legal contact execution	Unknown (modeled estimate)	2026	Internal sports-science prior	Tight five performance depends strongly on rugby-specific set-piece mechanics (binding/engagement), scrum/lineout/maul body positioning, ruck/maul discipline, and collision/tackling technique under rugby laws—none are trained by softball fielding, limiting carryover.	—
[228]	Softball Pitcher → Rugby union Tight five transferable-skill correlation estimate	Internal domain reasoning	2026	Sports science assistant synthesis	Estimated from limited overlap in general upper-body coordination, force-transfer learning, and ability to repeat effort under fatigue; reduced because tight five performance is dominated by scrummaging/ruck mechanics, body-positioning stability in set pieces, repeated collisions, and high-specificity strength/technique rather than throwing/pitching mechanics.	—
[229]	General skill-transfer reasoning: squash provides conditioning and footwork, but tight five success is dominated by scrum-specific set-piece technique and mass/force production under collision	Authors n/a	2026	Sports science knowledge (integrated heuristic; no single source cited)	Set near-zero correlation because any transferable elements (balance, repeated movement, basic reactive agility) are outweighed by rugby tight-five requirements: scrum binding/pressure mechanics, ruck/collision legality, set-piece timing, and contact-strength technique. Since correlation here is technique-only, the squash-to-scrum/close-contact technical overlap is minimal.	—
[230]	Skill-transfer priors for surfing → rugby union (tight five)	None (inference-based estimate)	2026	Internal sports-science reasoning	Estimated from limited overlap in transferable elements: general body control, ability to stay coordinated under unstable conditions, and repeated effort capacity. Strongly downweighted because tight-five success is dominated by rugby-specific collision technique, scrummaging/body mechanics, set-piece footwork and leverage, and repeated high-force contact sequencing—skills not trained by surfing. Std dev reflects variability in whether the surfer’s strengths are more general athleticism (slightly higher carryover) vs primarily board-balance/upper-body endurance (lower carryover).	Open source
[231]	Technique-only carry-over between a swimming endurance stroke and a contact-heavy rugby forward role	General skill-transfer synthesis	N/A	General sports science synthesis	Used as a low prior because while both involve conditioning and repeated execution under fatigue, tight-five success is dominated by scrum/set-piece technique and collision mechanics that are not trained in backstroke.	Open source
[232]	What predicts tight five performance vs backstroke determinants	Rugby tight five determinants (general coaching summaries)	N/A	General coaching & sports performance summaries	Used to separate overlap (general strength-endurance, technical discipline) from non-overlap (scrum binding/leg drive, ruck/maul set-piece mechanics, contact timing under constraints).	Open source
[233]	Limited overlap in learned contact/set-piece skills	Skill specificity: loose vs tight five contact and set-piece mechanics (reasoned estimate)	N/A	N/A	Kept correlation low because tight five success relies heavily on scrum technique, binding/engagement, collision patterns, and set-piece timing—skills swimming sprint backstroke does not train.	Open source
[234]	Some transfer via explosiveness and body coordination	Shared athletic qualities: short explosive bursts + coordination (reasoned estimate)	N/A	N/A	Adjusted slightly upward because sprint backstroke indicates good ability to initiate quickly, coordinate whole-body mechanics, and maintain form under short, intense fatigue—useful for repeated collision bursts.	Open source
[235]	Mismatch between swim force application and close-contact force demands	Force production mismatch and sustained contact skill emphasis (reasoned estimate)	N/A	N/A	Reduced further because tight five roles emphasize stable base, leverage in scrums, and repetitive collisions in a specific force-vector context, which differs from water propulsion/turn mechanics.	Open source
[236]	Breaststroke middle distance → rugby tight five transfer heuristic	Internal sports-science heuristic (coordination + endurance transfer; technique mismatch)	2026	N/A	Gives a small positive baseline from general ability to keep mechanics consistent under fatigue and tolerate repeated physical output. Penalizes strongly because tight-five success is dominated by scrum/set-piece strength, collision technique, leverage/positioning, and contact-specific skills not trained in breaststroke.	Open source
[237]	Aerobic efficiency and repeat-effort contribution	Internal conditioning/efficiency assumption	2026	N/A	Assumes middle-distance swimmers may have good conditioning and technical discipline, helping with repeated collision efforts and ruck work, but does not assume transfer of scrummaging technique.	Open source
[238]	Carry-over assessment: swimming sprint breaststroke → rugby union tight five (technique/coordination only; excludes mass/size/force predisposition)	Internal sports-science cross-skill mapping	2026	N/A	Used to estimate overlap via general attributes that can transfer: repeated high-intensity effort tolerance, whole-body coordination, and basic acceleration/execution under fatigue. Discounted because tight five performance is dominated by rugby-specific collision/contact technique, scrum/lineout mechanics, repeated set-piece learning, and ball-handling in heavy congestion—tasks not meaningfully trained by breaststroke sprinting. Any influence of power/strength is treated as smaller/secondary since physique advantages are excluded.	Open source
[239]	GeneratedSkill-Overlap Prior	Internal sports-science reasoning (generated transfer prior)	2026	N/A	Estimated carry-over from butterfly middle-distance swimming to rugby union tight five for technique/skill only. Shared elements: general coordination and maintaining movement quality under fatigue. Reduced substantially because tight five success is dominated by scrum/lineout set-piece technique, body-positioning, contact mechanics, and repeated collision/tackle skills that are not trained by butterfly.	Open source
[240]	Cross-sport transfer priors (swim sprint butterfly → rugby tight five)	Internal sports-science priors (no external dataset used)	2026	N/A	Started from a small positive correlation because both involve repeated high-effort work and whole-body coordination, but the tight-five roles emphasize very different contact/set-piece technique.	Open source
[241]	Shared athletic qualities vs scrum/contact skill mismatch	Motor learning & collision-tech specificity heuristic	2026	N/A	Kept the estimate low: tight-five success depends heavily on scrum mechanics, leverage/technique for collisions, body positioning, and set-piece stability. Swimming sprint butterfly contributes mainly general upper-body power and fatigue management, with limited direct learning of scrummaging and collision technique.	Open source
[242]	Generated estimate based on general conditioning transfer vs weak overlap in set-piece/contact technique and scrum mechanics from freestyle swimming	Authors n/a	2026	Internal sports-science reasoning	Used a low positive correlation because endurance freestyle can transfer some aerobic conditioning, body control, and training discipline, but tight-five rugby success is driven largely by scrum/lineout set-piece technique, collision/contact mechanics, and strength/power application patterns not taught by front-crawl distance swimming.	—
[243]	Transfer from swimming freestyle middle-distance to rugby union tight five set-piece/collision roles	General sports-science/skill-transfer heuristics (no single study used)	2026	Internal reasoning	Chosen a very low correlation: swimming transfers aerobic fitness and general coordination/training habits, but tight five success depends mainly on rugby-specific set-piece mechanics, contact/tackling technique, scrum driving coordination, and ball skills in traffic—largely absent in freestyle swimming. Technique overlap is minimal.	Open source
[244]	Transferable capacities mapping: sprint freestyle swimming → rugby union tight five	Conceptual sports-skill overlap model (no single study)	2026	Sports science assistant estimate	Estimated a small positive correlation by allowing general transferable elements from sprint freestyle (explosive power, whole-body coordination, ability to produce force repeatedly at high effort, and basic body control). Discounted major overlap because rugby tight-fives success is dominated by scrum/maul-specific technical skill, set-piece mechanics, strength-driven contact technique, and repeated collision tolerance—skills not trained in swimming sprint freestyle. Also treated size/mass/set-piece force production as largely trait/conditioning rather than technique under your rules.	Open source
[245]	Internal synthesis: limited transfer from table-tennis timing/precision to rugby tight-five collision/set-piece forces	Authors n/a	2026	Internal synthesis	Used to justify a small positive correlation: both can benefit from coordination and decision-making under pressure, but tight-five performance is dominated by scrum/maul technique, set-piece stability, and high-force collision mechanics—areas with little direct overlap with table-tennis racket/spin skills.	—
[246]	Taekwondo → rugby tight five: small general transfer via collision tolerance and athletic conditioning habits (internal reasoning)	Authors n/a	2026	Internal reasoning	Gives a very small baseline positive correlation because taekwondo builds some contact readiness, balance, and leg/hip strength patterns that can make early adaptation to collisions slightly easier.	—
[247]	Scrum/set-piece and collision-technique specificity (internal reasoning)	Authors n/a	2026	Internal reasoning	Reduces correlation because tight-five success is dominated by rugby-specific set-piece technique and body positioning (scrum engagement mechanics, maul/ruck bodywork, legal collision timing) not trained in taekwondo.	—
[248]	Mass/force and leverage components (non-visual traits) separation (internal reasoning)	Authors n/a	2026	Internal reasoning	Keeps the estimate framed on skills/technique; even though force/leverage matter, the key limiting factor is still sport-specific technique rather than generic strength.	—
[249]	Low transferable skill overlap to scrum/close-contact roles	Authors n/a	2026	Internal sports science heuristic	Set low baseline because tennis’s key skills (racket striking, court footwork, ball-tracking) don’t map well to tight five determinants: scrum technique, set-piece stability, collision timing, and close-contact strength/power mechanics.	—
[250]	Some general athleticism/conditioning transfer	Authors n/a	2026	Internal sports science heuristic	Add a small amount because tennis can build general coordination, lateral mobility, and practice habits that help learning physical roles, even if it doesn’t teach scrum technique.	—
[251]	Tight five roles depend strongly on physical/contact-specific technique (reduces correlation even further)	Authors n/a	2026	Internal sports science heuristic	Reduce because success in tight five is heavily driven by rugby-specific contact mechanics, binding/engagement technique, and repeated collision adaptation—highly specific and not trained by tennis.	—
[252]	General sports-science reasoning (transfer based on technique/skills/mentality overlap only)	Authors n/a	2026	Internal model/heuristic	Estimated carry-over from triathlon endurance/coordination to rugby union tight five roles, focusing on transferable endurance-of-effort, training discipline, and basic collision readiness while excluding physique/proportion leverage and recognizing scrum/collision/ruck set-piece technique is largely untrained in triathlon.	—
[253]	Cross-sport carryover heuristic (volleyball attacker → rugby tight five)	Internal domain reasoning	2026	N/A	Estimated very low positive correlation from general strength/power and collision tolerance from jumping/high-intensity efforts. Discounted heavily for major technical mismatch: rugby tight-five success depends on scrummaging mechanics, body positioning in set-pieces, binding/pressure technique, ruck/maul leg drive patterns, and repeated collision skills under rugby contact rules—skills volleyball attackers do not train. Also treated as excluding body-proportion advantages (mass/leverage).	Open source
[254]	Libero → tight five: limited overlap beyond general athletic coordination	Skill overlap mapping (volleyball libero reactive defense ↔ scrum close-contact roles)	2026	Sports science reasoning	Used to keep correlation near zero because any transferable component is mostly general coordination/reaction, while tight five success is dominated by scrum mechanics, set-piece technique, collision tolerance, and strength-related force application (which are largely different from digging/reception).	—
[255]	Set-piece/contact specialization reduces technique transfer	Bayesian prior for low transfer when future role is contact/set-piece specialized, titleExpansions_needed_placeholder_for_model_safety_note:, publisher:dummy_does_not_matter, year:2026,, short_name:prior:, url:, use:Used to justify low mean and relatively small std dev for a technique-only transfer metric between court defense and scrum specialist mechanics.	2026	Sports science generalization	Applied to prevent overestimating: tight five performance depends strongly on scrum/collision technique and force production patterns that volleyball libero does not train.	—
[256]	Skill/transfer heuristic: volleyball middle blocker → rugby union tight five	Internal sports-skill overlap heuristic (no external dataset used)	2026	N/A	Estimated low carry-over. Volleyball middle blocker transfers some general coordination/explosiveness and willingness to engage in timing-critical collisions at the net, but rugby tight five performance is dominated by scrum/set-piece technique, body positioning, collision/tackle mechanics at close quarters, and repeated high-force contact within laws—skills volleyball does not train. Correlation kept small with moderate uncertainty.	Open source
[257]	Expert-informed transfer estimate (volleyball setter → rugby union tight five)	Authors n/a	2026	Internal knowledge synthesis	Used to estimate skill/mentality carry-over from volleyball setter (vision/timing, coordination, general athleticism) to rugby tight five (set-piece scrummaging, body positioning, collision mechanics, repeated high-force contact), while discounting that tight five outcomes are dominated by rugby-specific contact/set-piece technique and physical-force production patterns.	Open source
[258]	Transfer of learning: combat grappling → close-contact stability skills	Transfer of learning: contact/body control under resistance	2026	Internal synthesis (no single paper cited)	Justifies a small positive correlation because wrestling trains balance, leverage, and maintaining position during physical resistance—useful in scrum/close-contact work.	Open source
[259]	Tight five performance depends on rugby-specific scrummaging mechanics and legality	Rugby tight five determinants (set-piece and collision repetition)	2026	Internal synthesis (no single paper cited)	Keeps correlation low because tight five success depends strongly on rugby set-piece technique (binding/engagement, legality, coordination), plus specific collision patterns and conditioning.	Open source
[260]	Scrum work is highly rule- and technique-specific compared with wrestling clinch/grappling	Technique specialization constraint (wrestling clinch vs scrum mechanics)	2026	Internal synthesis (no single paper cited)	Prevents the correlation from becoming moderate-high: wrestling does not directly teach scrum engagement angles, timing, and coordinated forward drive mechanics.	Open source