People who naturally have a longer lever arm between their kneecap and knee joint tend to get stronger in eccentric movements (like lowering a weight) after training, likely because their anatomy gives them a mechanical advantage.
Scientific Claim
In previously untrained men, pre-training patellar tendon moment arm distance is associated with eccentric strength gains after 10 weeks of heavy resistance training, with models including this variable receiving substantial statistical support.
Original Statement
“The change in % VA and pre-training moment arm distance had substantial support for use in eccentric torque prediction models (AICC < 2)”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim correctly uses 'associated with' and references AICc support, which is the appropriate inference from this observational design. No causal language is used.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Randomized Controlled TrialLevel 1bThat individuals with longer patellar tendon moment arms gain more eccentric strength than those with shorter arms when given identical training.
That individuals with longer patellar tendon moment arms gain more eccentric strength than those with shorter arms when given identical training.
What This Would Prove
That individuals with longer patellar tendon moment arms gain more eccentric strength than those with shorter arms when given identical training.
Ideal Study Design
A double-blind RCT of 120+ untrained men aged 18–40, stratified by pre-training moment arm (high vs. low quartile), randomized to identical 10-week eccentric-focused resistance training, measuring eccentric torque gain and controlling for CSA and EMG:M.
Limitation: Cannot isolate whether the effect is due to moment arm alone or correlated traits like muscle-tendon stiffness.
Longitudinal Cohort StudyLevel 2bIn EvidenceWhether pre-training moment arm consistently predicts eccentric strength gains across individuals.
Whether pre-training moment arm consistently predicts eccentric strength gains across individuals.
What This Would Prove
Whether pre-training moment arm consistently predicts eccentric strength gains across individuals.
Ideal Study Design
A prospective cohort of 250+ untrained adults undergoing 10 weeks of standardized heavy resistance training, with pre-training moment arm measured via X-ray and post-training eccentric torque assessed, testing for correlation while controlling for CSA and EMG:M.
Limitation: Cannot rule out that moment arm correlates with other unmeasured biomechanical factors.
Cross-Sectional StudyLevel 3Whether individuals with longer moment arms have greater eccentric strength capacity at baseline.
Whether individuals with longer moment arms have greater eccentric strength capacity at baseline.
What This Would Prove
Whether individuals with longer moment arms have greater eccentric strength capacity at baseline.
Ideal Study Design
A cross-sectional analysis of 300+ healthy adults aged 20–50, measuring patellar tendon moment arm via X-ray and maximal eccentric torque, controlling for muscle size and age.
Limitation: Cannot determine if moment arm causes higher strength or if stronger individuals develop longer arms over time.
Evidence from Studies
Supporting (1)
The study found that men who started with a longer patellar tendon lever arm gained more eccentric strength after 10 weeks of weight training — exactly what the claim says.