Measuring Hamstring Strength, Imbalance, And Injury History In Older Active Adults: A Baseline Study

Hamstring strength plays an important role in daily activities such as walking, running, and climbing stairs. Strong hamstrings reduce the risk of injury, stabilize lower extremity joints, and may lower the chance of repeat injury in athletes and older adults. As exercise is more and more accepted and encouraged as medicine, there will be increasing need for knowledge about active older populations. Measuring, analyzing, reporting, discussing, and publishing findings about active older populations will establish foundational knowledge within the literature. PURPOSE: We measured active older adults performing eccentric nordic curls to establish baseline levels of hamstring strength and impact of past injury on hamstring imbalance. Based on previous findings in athletes, we hypothesize there will be less inter-leg hamstring imbalance in the injured group (HSI) than in the uninjured group (no HSI). METHODS: Seventy-two participants (40 F, 32 M; age: 67.0 ± 8.3; height 170.6 ± 10.3 cm; weight 71.5 ± 13.1 kg) performed at least two repetitions of an eccentric hamstring curl. Participants self-reported previous hamstring injuries (HSI). We analyzed differences between the no HSI group (strong - weak leg) and the HSI group (non-injured - injured legs). Participants with bilateral injury history were excluded from this analysis. RESULTS: Males generated more absolute force than females (M: 411 ± 89.3 N, F: 286.6 ± 92.1 N, t-test: p < 0.001), in force per kg body mass males generated more force than females (M: 5.2 ± 1.2 N/kg, F: 4.4 ± 1.2 N/kg, p < 0.012). Between HSI (n = 15) and no HSI (n = 47) groups, the mean difference between leg measurements in HSI was 1.16 ± 29.01 N and the difference between strong and weak legs in no HSI was 21.64 ± 18.19 N (between group difference p < 0.020). CONCLUSION: We found support for our hypothesis. Publishing baseline findings and establishing foundation for strength and performance metrics in an older, active population gives a basis for continuing research which may lead to better quality of life and reduced injury risk.