Yong Jennifer R, Silder Amy, Delp Scott L
Departments of Mechanical Engineering, USA.
Bioengineering, Stanford University, USA.
J Biomech. 2014 Nov 28;47(15):3593-7. doi: 10.1016/j.jbiomech.2014.10.015. Epub 2014 Oct 23.
Running research has focused on reducing injuries by changing running technique. One proposed method is to change from rearfoot striking (RFS) to forefoot striking (FFS) because FFS is thought to be a more natural running pattern that may reduce loading and injury risk. Muscle activity affects loading and influences running patterns; however, the differences in muscle activity between natural FFS runners and natural RFS runners are unknown. The purpose of this study was to measure muscle activity in natural FFS runners and natural RFS runners. We tested the hypotheses that tibialis anterior activity would be significantly lower while activity of the plantarflexors would be significantly greater in FFS runners, compared to RFS runners, during late swing phase and early stance phase. Gait kinematics, ground reaction forces and electromyographic patterns of ten muscles were collected from twelve natural RFS runners and ten natural FFS runners. The root mean square (RMS) of each muscle׳s activity was calculated during terminal swing phase and early stance phase. We found significantly lower RMS activity in the tibialis anterior in FFS runners during terminal swing phase, compared to RFS runners. In contrast, the medial and lateral gastrocnemius showed significantly greater RMS activity in terminal swing phase in FFS runners. No significant differences were found during early stance phase for the tibialis anterior or the plantarflexors. Recognizing the differences in muscle activity between FFS and RFS runners is an important step toward understanding how foot strike patterns may contribute to different types of injury.
跑步研究一直聚焦于通过改变跑步技术来减少损伤。一种提出的方法是从后脚着地（RFS）转变为前脚着地（FFS），因为FFS被认为是一种更自然的跑步模式，可能会减少负荷和受伤风险。肌肉活动会影响负荷并影响跑步模式；然而，自然前脚着地跑步者和自然后脚着地跑步者之间的肌肉活动差异尚不清楚。本研究的目的是测量自然前脚着地跑步者和自然后脚着地跑步者的肌肉活动。我们测试了以下假设：与后脚着地跑步者相比，在前脚着地跑步者的摆动末期和站立初期，胫骨前肌的活动会显著降低，而跖屈肌的活动会显著增加。从12名自然后脚着地跑步者和10名自然前脚着地跑步者身上收集了步态运动学、地面反作用力和10块肌肉的肌电图模式。在摆动末期和站立初期计算每块肌肉活动的均方根（RMS）。我们发现，与后脚着地跑步者相比，前脚着地跑步者在摆动末期胫骨前肌的RMS活动显著降低。相反，在摆动末期，前脚着地跑步者的腓肠肌内侧头和外侧头的RMS活动显著增加。在站立初期，胫骨前肌或跖屈肌未发现显著差异。认识到前脚着地跑步者和后脚着地跑步者之间的肌肉活动差异是理解着地方式如何导致不同类型损伤的重要一步。
