Measuring eccentric hamstring strength in senior athletes: reference values, age and sex associations, and limb asymmetry

Participation in Masters sport has increased; however, reference eccentric hamstring strength values are unavailable. Instrumented Nordic hamstring exercise (NHE) testing is used in younger athletes, but reports for senior athletes are lacking.

Establish sex-stratified reference values for senior athletes. Secondary aims examined associations with age, sex, and inter-limb asymmetry.

This study included 203 senior athletes (100 female) and measured eccentric hamstring strength during testing. Absolute peak force, relative peak force, and limb asymmetry were calculated.

Mean unilateral absolute peak force was 156 N in females and 242 N in males, corresponding to relative values of 2.46 N/kg and 2.99 N/kg, respectively. Males demonstrated greater absolute peak force (mean difference: 85.6 95% CI 70.2 to 100.9; d = 1.54, 95% CI 1.22 to 1.85) and greater relative peak force (mean difference: 0.53N/kg, 95% CI 0.34 to 0.73; d = 0.76, 95% CI 0.47 to 1.04). Increasing age was associated with lower absolute peak force (-2.10 N/year, 95% CI -3.09 to -1.11) and lower relative peak force (-0.020 N/kg/year, 95% CI -0.033 to -0.008). Mean asymmetry was 11.6 ± 8.8% (75th percentile: 16.1%). Asymmetry was not significantly associated with age or sex.

This study provides the first reference eccentric hamstring strength values for senior athletes. Male athletes demonstrated greater absolute and relative strength than females, whereas increasing age was associated with lower strength despite high physical activity levels. Common asymmetry thresholds may overclassify high-functioning senior athletes as having concerning inter-limb asymmetry, highlighting the need for population-specific interpretation.