Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
Faculty of Nursing, University of Calgary, Calgary, AB, Canada.
J Foot Ankle Res. 2011 Feb 4;4:6. doi: 10.1186/1757-1146-4-6.
The tibialis posterior muscle is believed to play a key role in controlling foot mechanics during the stance phase of gait. However, an experiment involving localised tibialis posterior muscle fatigue, and analysis of discrete rearfoot and forefoot kinematic variables, indicated that reduced force output of the tibialis posterior muscle did not alter rearfoot and forefoot motion during gait. Thus, to better understand how muscle fatigue affects foot kinematics and injury potential, the purpose of this study was to reanalyze the data and investigate shank, rearfoot and forefoot joint coupling and coupling variability during walking.
Twenty-nine participants underwent an exercise fatigue protocol aimed at reducing the force output of tibialis posterior. An eight camera motion analysis system was used to evaluate 3 D shank and foot joint coupling and coupling variability during treadmill walking both pre- and post-fatigue.
The fatigue protocol was successful in reducing the maximal isometric force by over 30% and a concomitant increase in coupling motion of the shank in the transverse plane and forefoot in the sagittal and transverse planes relative to frontal plane motion of the rearfoot. In addition, an increase in joint coupling variability was measured between the shank and rearfoot and between the rearfoot and forefoot during the fatigue condition.
The reduced function of the tibialis posterior muscle following fatigue resulted in a disruption in typical shank and foot joint coupling patterns and an increased variability in joint coupling. These results could help explain tibialis posterior injury aetiology.
人们认为胫骨后肌在步态站立阶段控制足部力学中起着关键作用。然而，一项涉及胫骨后肌局部疲劳的实验，并对离散的后足和前足运动学变量进行分析，表明胫骨后肌的力输出减少并没有改变步态中的后足和前足运动。因此，为了更好地了解肌肉疲劳如何影响足部运动学和受伤的可能性，本研究的目的是重新分析数据，并研究行走时小腿、后足和前足关节的耦合和耦合变异性。
29 名参与者接受了一项旨在降低胫骨后肌力输出的运动疲劳方案。使用八相机运动分析系统评估了在跑步机行走过程中 3D 小腿和足部关节的耦合以及耦合变异性，分别在疲劳前和疲劳后进行评估。
疲劳方案成功地将最大等长力降低了 30%以上，并使小腿在横平面上和前足在矢状面和横平面上相对于后足在额状面上的运动的耦合运动增加。此外，在疲劳状态下，还测量到小腿和后足之间以及后足和前足之间的关节耦合变异性增加。
疲劳后胫骨后肌功能的降低导致典型的小腿和足部关节耦合模式中断，并增加了关节耦合的变异性。这些结果可以帮助解释胫骨后肌损伤的病因。
