Abstract：
Hamstring strain injuries would frequently occur during the late swing phase of sprinting, while increasing biceps femoris long head\'s (BFlh) fascicle length induced by eccentric contraction exercises can reduce the risk of strain injuries. Thus, using a musculoskeletal modelling simulation, we examined how manipulating BFlh optimal muscle fibre length would change muscle force during the late swing phase of sprinting for providing knowledge preventing hamstring strain injuries. A motion capture system was used to collect kinematic data from 40 male athletes during maximal speed sprinting. Muscle force and force-generating capabilities determined by force-length-velocity properties were estimated with three BFlh optimal muscle fibre lengths (90%, 110% and 120%), which were perturbed from the nominal (100%). During the late swing phase of sprinting, the muscle force and force-generating capabilities, induced by the force-length property rather than the force-velocity property, were increased by increases in BFlh optimal muscle fibre length. Moreover, magnitudes of the simulated increases in muscle force and force-generating capabilities were correlated with the peak BFlh muscle-tendon unit length. These results demonstrate that lengthening BFlh optimal muscle fibre might increase muscle force during the late swing phase, and the magnitude of increment would be associated with increasing muscle-tendon unit length.
摘要：
腿筋拉伤经常发生在短跑的摆动后期，偏心收缩运动引起的股二头肌长头（BFlh）束长度的增加可以降低劳损的风险。因此，使用肌肉骨骼建模模拟，我们研究了在短跑后期摆动阶段操纵BFlh最佳肌纤维长度如何改变肌肉力量，以提供预防腿筋拉伤的知识。运动捕获系统用于在最大速度冲刺期间从40名男性运动员收集运动学数据。通过三个BFlh最佳肌纤维长度（90％，110%和120%)，从标称值(100%)扰动。在短跑的后期挥杆阶段，肌肉力量和力量生成能力，由力-长度特性而不是力-速度特性引起，通过BFlh最佳肌纤维长度的增加而增加。此外，肌肉力量和力量产生能力的模拟增加幅度与BFlh肌肉肌腱单位长度的峰值相关。这些结果表明，延长BFlh最佳肌纤维可能会在摆动后期增加肌肉力量，并且增量的大小与肌肉肌腱单位长度的增加有关。
