Injury Mechanism of Bi-articular Muscle Hamstring during Sprint Running

Abstract

Many mechanisms and risk factors of hamstring injury were implicated. In sprinting, the greatest length of the hamstring muscle occurs during later swing phase. However, maximal muscle torque at knee joint and consequent stress on muscle occurs during stance phase. In present paper, we apply the intersegmental dynamics and the optimization model combined with kinematics, ground reaction force (GRF) and Electromyography （EMG）measurement to study the injury mechanisms of hamstring muscle. The findings of intersegmental dynamics analysis revealed that the GRF produced a large extension torque at knee joint during the initial stage of stance phase, meanwhile, the hamstring muscle was required to generate a flexion torque in order to counteract the effect of GRF, this may contribute to the occurrence of hamstring injury. This kind of analysis provides a new approach for understanding the mechanisms of hamstring injury.