Faculty of Sport Sciences, Waseda University, Tokyo, Japan.
Department of Kinesiology, San José State University, CA, USA.
J Sports Sci Med. 2021 Mar 12;20(2):275-283. doi: 10.52082/jssm.2021.275. eCollection 2021 Jun.
The semitendinosus (ST) muscle is primarily used during Nordic hamstring exercise (NHE), which is often prescribed for preventing hamstring injury, though the biceps femoris long head (BFlh) muscle that is more susceptible to injuries. Thus, this study aimed to identify the modulation of BFlh muscle activity with different knee flexion angles during NHE using an inclined platform. Fourteen male athletes performed NHE and maintained their position at maximum inclination (NH). Subjects also performed isometric NHE using a platform inclined to 50° (ICL) and 40° (ICH), and the knee flexion angle was controlled to 50° and 30°. The electromyography (EMG) activity of the BFlh, ST, semimembranosus, gluteus maximus, elector spinae, and rectus abdominus muscles was determined during each exercise. The EMG of the ST was higher than that of the BFlh during NHE and the highest of all muscles in all exercises (p < 0.05). Moreover, the activity of the BFlh tended to be higher than that of the ST for ICH than for ICL, regardless of the knee joint angle. The activity of the BFlh becomes equivalent to that of the ST during NHE at a knee flexion angle of less than 50°. These results indicate that performing NHE at a shallow knee flexion angle will enhance the activity of the BFlh muscle.
半腱肌（ST）肌肉在北欧腘绳肌练习（NHE）中主要使用，尽管更易受伤的股二头肌长头（BFlh）肌肉，但 NHE 常用于预防腘绳肌受伤。因此，本研究旨在使用倾斜平台确定不同膝关节屈曲角度下 NHE 期间 BFlh 肌肉活动的调节。14 名男性运动员进行了 NHE，并保持在最大倾斜位置（NH）。受试者还使用倾斜至 50°（ICL）和 40°（ICH）的平台进行等长 NHE，控制膝关节角度至 50°和 30°。在每项运动中，都确定了 BFlh、ST、半膜肌、臀大肌、腰方肌和腹直肌的肌电图（EMG）活动。在 NHE 期间，ST 的 EMG 高于 BFlh，在所有运动中均高于所有肌肉（p<0.05）。此外，无论膝关节角度如何，ICH 时 BFlh 的活动都比 ICL 时高。在膝关节屈曲角度小于 50°时，NHE 期间 BFlh 的活动与 ST 相当。这些结果表明，在浅膝关节屈曲角度下进行 NHE 将增强 BFlh 肌肉的活动。
