Introduction Hamstring strength deficits have been identified as risk factors for ACL and muscular injuries, with hamstring strain being the most prevalent muscle injuries in soccer. The aim of this study was to investigate hamstring eccentric strength before and after a soccer match in soccer athletes.

Material and Methods Hamstring eccentric strength was measured in 64 healthy male and female competitive football athletes (14-25 years) during the execution of the Nordic hamstring exercise (NHE test) before and after a soccer match. Anterior-knee laxity (AKL) was quantified as well.

Results Mean and absolute eccentric hamstring peak torque decreased by 24.5 Nm (p<0.005) and 21.9 Nm (p<0.0005) in females, whereas males improved by 19.9 Nm (p=0.01) and 20.9 Nm (p=0.02), respectively. Hamstring’s total work in females decreased by 831.1 J (p<0.0005) compared to the males’ reduction of 235.3 J. Both pre- vs. post-match intersex mean and absolute eccentric HS peak torque changes were significant (p<0.0005), as the changes in HS total work (p=0.007). Pre- vs. post-match AKL difference and dominant vs. nondominant limb comparison of strength parameters were not significantly different. Younger female athletes (14-19 years old) presented a greater decrease in mean and absolute peak HS eccentric strength than those in older female and overall male athletes.

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 in males. The 14- to 19-year-old female athletes subgroup experienced the highest reduction.