419 FO77 – Higher eccentric hamstring muscle fatigue after participation in a soccer match in young female athletes

Background Hamstring (HS) strength deficits and imbalances have been identified as risk factors for sustaining ACL injuries and muscular strains, with HS injuries being the most prevalent muscle injuries in soccer athletes. Objective The aim was to investigate HS eccentric strength before and after a football match in male and female athletes. The hypothesis is that HS fatigue could depend on sex. Design Cohort observational study. Setting Semi-professional football. Participants Sixty-four healthy men and women semi-professional football players aged from 14 to 25 years. Interventions HS eccentric strength during the execution of the Nordic hamstring exercise (NHE test) and anterior-knee laxity (AKL) were measured before and after a 90-minute soccer match. Main Outcome Measurements The pre- and post-match difference between genders in HS eccentric strength (mean and absolute peak torque and total work) and in AKL. Results Mean and absolute eccentric HS peak torque decreased by 4.5 Nm (p<0.0005) and 21.9 Nm (p<0.0005) in females, whereas male peers improved by 19.9 Nm (p=0.01) and by 20.9 Nm (p=0.02), respectively. HS total work in females decreased by 831.1 J (p<0.0005) compared to the males' reduction of 235.3 J. Both the pre- vs. postmatch intersex mean and absolute eccentric HS peak torque changes were significant (p<0.0005), as were the changes in HS total work (p=0.007). The pre- vs. postmatch AKL difference was not significantly different. Younger female athletes (14–19 years old) presented a greater decrease in mean and absolute peak HS eccentric strength compared to those in older female athletes and males. Conclusions HS eccentric strength and work differ based on the athlete's sex, as measured by the NHE test. Mean peak, absolute peak, and total work showed greater reductions in females than those in their male peers. The subgroup of 14- to 19-year-old female athletes experienced the highest reduction in strength.