The Effect Of A 6-week Eccentric Hamstring Training Intervention On Sprint Acceleration

Eccentric (ECC) training of the hamstrings can improve muscle strength and may subsequently enhance athletic performance. Acceleration, a key component of sprinting performance, is influenced by hamstring strength. However, it is unclear how hip- and knee-dominant hamstring exercises specifically influence sprint acceleration. PURPOSE: To determine changes in initial, early, and late acceleration phases in a 60 m sprint after a 6-week ECC intervention performing either the Nordic Hamstring Exercise (NHE) or Romanian deadlift (RDL). METHODS: Participants were randomly assigned to RDL or NHE training groups. Testing was performed prior to (PRE), after the intervention (POST), and after 2 weeks of detraining (DT). Timing gates were placed at 0, 5, 10, and 20 m to calculate acceleration for initial (0 to 5 m), early (0 to 10 m), and late acceleration (0 to 20 m). Separate linear mixed effects models were used to assess differences between groups and across time. RESULTS: A total of 25 participants were included (RDL: n = 12, age: 20.6 (0.8) years, height: 1.72 (0.1) m, mass = 68.9 (9.0) kg, males = 7; NHE: n = 13, age: 21.0 (1.1) years, height: 1.72 (0.1) m, mass = 70.0 (10.9) kg, males = 6). A significant effect of time was found for acceleration from 0 to 5 m (p = 0.03) but not for 0 to 10 m (p = 0.15) or 0 to 20 m (p = 0.22). Mean differences in acceleration from 0 to 5 m between PRE-POST, POST-DT, and PRE-DT were 0.27 [-0.03, 0.58] m/s2 (p = 0.08), 0.04 [-0.28, 0.35] m/s2 (p = 0.95), and 0.31 [0.001, 0.62] m/s2 (p = 0.04), respectively. There were no differences between training groups in 0 to 5 m (p = 0.90), 0 to 10 m (p = 0.73), or 0 to 20 m acceleration (p = 0.53). CONCLUSION: ECC training of the hamstrings, regardless of exercise, improved initial acceleration. The improvement in 0 to 5 m acceleration may reflect increased horizontal force production in the initial push-off of a sprint. These improvements were maintained after 2 weeks of detraining, suggesting performance enhancements in initial acceleration from ECC training are robust to short rest periods. Sprint mechanics likely have a more pronounced effect beyond the initial acceleration, possibly explaining the lack of significant improvement in the later phases. ECC hamstring training, such as NHE or RDL, could be valuable for athletes seeking sustained improvements in early-stage acceleration.