Tracking of time-dependent changes in concentric and eccentric quadriceps and hamstring torques and powers after a half-marathon.

The increasing participation in running events, particularly half-marathons, has been noteworthy in recent decades. However, the time course of recovery of muscle performance after a half-marathon running remains largely unclear. This study aimed to investigate changes in concentric and eccentric quadriceps and hamstring peak torques and mean powers, as well as hamstring to quadriceps torque and power ratios, after a half-marathon. Thirty-eight recreational runners participated in this study. Isokinetic dynamometry was used to measure peak torque and mean power at four time points: pre (baseline), immediately post (within 5 min), 1 day post and 2 days post half-marathon running. Compared with baseline measurements, reductions were observed in concentric and eccentric quadriceps and hamstring peak torques (p < 0.001) and mean powers (p < 0.001), reductions in eccentric hamstring to concentric quadriceps torque ratios (p < 0.001) and power ratios (p = 0.033). Most measured parameters recovered to baseline within 1 day, except concentric quadriceps peak torques and mean powers, which were restored within 2 days. By the second day, we also observed supercompensation in concentric hamstring and eccentric quadriceps peak torques and mean powers. These findings suggest that recreational runners should avoid high-intensity exercise within 2 days after a half-marathon to minimize injury risk.