a Head Office for Information Systems and Cybersecurity , RIKEN , Saitama , Japan.
b Department of Human Sciences , Kanagawa University , Kanagawa , Japan.
J Sports Sci. 2019 Sep;37(17):1972-1980. doi: 10.1080/02640414.2019.1610146. Epub 2019 Apr 29.
This study aimed to investigate the influence of foot strike patterns on the behaviour of the triceps surae muscle-tendon unit, including the Achilles tendon whose length nearly corresponds to force of the triceps surae, and the medial gastrocnemius muscle (MG) during running. Seven male volunteers ran with forefoot and rearfoot strikes at 10, 14 and 18 km h on a treadmill. The MG fascicle length was measured using ultrasonography. The length of the curved Achilles tendon was quantified by combining ultrasonography with optical motion capture of reflective markers on the right lower limb and an ultrasound probe. The forefoot strike resulted in a significantly shorter MG fascicle length at the initial contact, at Achilles tendon peak elongation, and at toe-off, than the rearfoot strike. The Achilles tendon length at initial contact was greater during the forefoot strike than during the rearfoot strike at 18 km h, while its peak elongation was not significantly different during forefoot and rearfoot running. These results indicate that the MG, with a shorter length during forefoot running, manages to address demands for a similar peak force of the triceps surae than during rearfoot running.
本研究旨在探讨足着地方式对小腿三头肌-肌腱复合体行为的影响，包括跟腱（其长度几乎与小腿三头肌的力相对应）和内侧腓肠肌（MG）在跑步过程中的行为。7 名男性志愿者在跑步机上以前脚和后脚着地的方式分别以 10、14 和 18km/h 的速度跑步。使用超声检查测量 MG 肌腹长度。通过将超声与右下肢反光标记的光学运动捕捉以及超声探头相结合，定量测量弯曲跟腱的长度。前脚着地在初始接触、跟腱最大伸长和足趾离地时，MG 肌腹长度明显短于后脚着地。在 18km/h 时，前脚着地时初始接触时的跟腱长度大于后脚着地，而最大伸长时前后脚跑步时没有显著差异。这些结果表明，MG 在前脚跑步时长度较短，但能够满足与后脚跑步时相似的小腿三头肌峰值力的要求。
