Hamstring muscle function during knee flexion has been linked to hamstring injury and performance. However, it is unclear whether knee flexion alone (KF) requires similar hamstring electromyography (EMG) activity pattern to simultaneous hip extension and knee flexion (HE-KF), a combination that occurs in the late swing phase of sprinting. This study examined whether HE-KF maximal voluntary isometric contraction (MVIC) evokes higher (EMG) activity in biceps femoris long head (BFlh) and semitendinosus (ST) than KF alone. Effects of shank rotation angles were also tested. Twenty-one males performed the above-mentioned MVICs while EMG activity was measured along ST and BFlh. Conditions were compared using a one-way mixed functional ANOVA model under a fully Bayesian framework. Higher EMG activity was found in HE-KF in all shank rotation positions than in KF in the middle region of BFlh (highest in the 9th channel, by 0.022 mV [95%CrI 0.014 to 0.030] in neutral shank position). For ST, this was only observed in the neutral shank position and in the most proximal channel (by 0.013 mV [95%CrI 0.001 to 0.025]). We observed muscle- and region-specific responses to HE-KF. Future studies should examine whether hamstring activation in this task is related to injury risk and sprint performance.

膝关节屈曲期间的绳肌功能与绳肌损伤和表现有关。但是，尚不清楚单独的膝关节屈曲（KF）是否需要与同时进行的髋部伸展和膝盖屈曲（HE-KF）类似的绳肌肌电图（EMG）活动模式，这种组合发生在短跑的后期摆动阶段。这项研究检查了HE-KF股二头肌长头（BFlh）和半腱肌（S​​T）是否比单独的KF引起更高的主动等距收缩（MVIC）活动。还测试了柄旋转角度的影响。21名男性进行了上述MVIC，同时沿ST和BFlh测量了EMG活性。在完全贝叶斯框架下，使用单向混合功能方差分析模型比较条件。在所有刀柄旋转位置，HE-KF的EMG活性均高于BFlh中部区域的KF（在第9通道中最高，在中性刀柄位置，其EMG活性为0.022 mV [95％CrI 0.014至0.030]）。对于ST，仅在中性柄位置和最近端的通道中观察到此现象（0.013 mV [95％CrI 0.001至0.025]）。我们观察到了针对HE-KF的肌肉和区域特异性反应。未来的研究应检查此任务中的绳肌激活是否与伤害风险和短跑表现有关。