This study aimed to determine the acute effects of static stretching of the hamstrings on maximal sprint speed and its spatiotemporal variables and lower-limb kinematics during the late swing phase, as well as the relationship with Nordic hamstring strength. The study had a within-participant experimental design. Sixteen healthy male college sprinters were asked to sprint 80 m without static stretching and with static stretching of the hamstrings for 4 × 30 s per leg before the sprint; both conditions were counterbalanced. The knee flexion peak torque was measured using the Nordic hamstring. The differences between no static stretching and static stretching as well as their relationship with Nordic hamstring strength were investigated. The results showed that the touchdown distance (p = .036) significantly increased following static stretching. Although not significant, maximal sprint speed decreased (p = .086), and the theoretical hamstring length (difference between knee angle and hip angle) at ipsilateral touchdown was greater (p = .069) following static stretching. In addition, a lower peak torque of the Nordic hamstring resulted in a more significant decrease in maximal sprint speed following static stretching. Therefore, static stretching of the hamstring just before sprinting may increase the theoretical hamstring length during the late swing phase at maximal sprint speed and induce kinematics that increases the hamstring strain injury risk. Moreover, it is suggested that improving the Nordic hamstring strength may help minimize the negative effects of static stretching on the hamstrings.

本研究旨在确定腿筋静态拉伸对最大冲刺速度及其时空变量和摆动后期下肢运动学的急性影响，以及与北欧腿筋力量的关系。该研究采用了参与者内部的实验设计。 16 名健康男性大学短跑运动员被要求在不进行静态拉伸的情况下冲刺 80 m，并在冲刺前每条腿进行 4 × 30 s 的静态拉伸；这两个条件都得到了平衡。使用北欧腿筋测量膝关节弯曲峰值扭矩。研究了无静态拉伸和静态拉伸之间的差异以及它们与北欧腿筋力量的关系。结果表明，静态拉伸后触地距离 ( p  = .036) 显着增加。虽然不显着，但静态拉伸后最大冲刺速度降低了 ( p  = .086)，并且同侧触地时的理论腿筋长度（膝盖角度和臀部角度之间的差异）更大 ( p  = .069)。此外，北欧腿筋的峰值扭矩较低，导致静态拉伸后最大冲刺速度更显着下降。因此，在冲刺前对腘绳肌进行静态拉伸可能会增加最大冲刺速度下摆动后期的理论腘绳肌长度，并诱发增加腘绳肌拉伤风险的运动学。此外，建议提高北欧腿筋力量可能有助于最大限度地减少静态拉伸对腿筋的负面影响。