اثر خستگي شبيه سازي شده بازي هندبال بر نسبت گشتاور ايزوكينتيك عضلات همسترينگ به چهار سر ران و عضلات اينورتور به اِوِرتور مچ پاي هندباليست هاي حرفه اي

Handball is a team and competitive sport at different levels with high injury preva‎lence. Lower limb injuries in the knee and ankle regions are most common in the handball players. Handball due to its time-consuming nature, exposes athletes to some degrees of fatigue, hence, most of the injuries occur at the end of the match. The behavior of the knee and ankle joints surrounding muscles of handball players in fatigue conditions has been less addressed. The purpose of the present study was to investigate the effect of simulated handball protocol induced-fatigue on the isokinetic hamstring to the quadriceps torque ratio and the isokinetic invertor to the evertor muscles in professional handball players. Peak isokinetic torque of the hamstring, quadriceps, evertor and invertor muscles of handball players at three angular velocities of 60, 120 and 180 degrees per second was measured in 30 professional handball players before and after the fatigue protocol by Biodex isokinetic dynamometer. Multivariate analysis of variance for repeated measurement was utilized to investigate the effect of fatigue on the outcomes. The results showed that handball simulation protocol induced fatigue decreased the hamstring muscles peak torque at angular velocities of 60 degrees/s (p=0.001), 120 degrees/s (p=0.002) and 180 degrees/s (p=0.001). Fatigue decreased peak isokinetic torque of quadriceps muscles at angular velocities of 60°/s (p=0.009) and 180°/s (p=0.037). Fatigue decreased peak isokinetic torque of invertors in 60 degrees/s (p=0.001). Also, fatigue decreased evertors peak isokinetic torque at the angular velocities of 60 degrees/s (p=0.001), 120 degrees/a (p=0.001) and 180 degrees/s (p=0.001). Fatigue decreased the ratio of hamstring to quadriceps maximum torque at angular velocities of 60 degrees/s (p=0.013), 120 degrees/s (p=0.018) and 180 degrees/s (p=0.002) and causes an increase in the torque ratio of inverter to evertor muscles at angular velocities of 60 degrees/s (p=0.042), 120 degrees/s (p=001) and 180 degrees/s (p=0.003). According to the findings of this study, it can be concluded that fatigue decreases lower limb muscles peak torque and hamstring to quadriceps muscles peak torque ratio, and increases invertor to evertor muscles peak torque ratio in handball players. This decreased muscles peak torque increases the risk of injury in ankle and knee. In order to prevent the adverse effects of fatigue, handball coaches are advised to develop the strength and endurance of the hamstring and evertor muscles to reduce the advert effects of fatigue.

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