Di Nardo Francesco, Mengarelli Alessandro, Maranesi Elvira, Burattini Laura, Fioretti Sandro
Department of Information Engineering, Università Politecnica delle Marche, 60131 Ancona, Italy.
Department of Information Engineering, Università Politecnica delle Marche, 60131 Ancona, Italy.
J Electromyogr Kinesiol. 2015 Apr;25(2):347-54. doi: 10.1016/j.jelekin.2014.10.016. Epub 2014 Nov 7.
The study was designed to assess the co-contractions of tibialis anterior (TA) and gastrocnemius lateralis (GL) in healthy young adults during gait at self-selected speed and cadence, in terms of variability of onset-offset muscular activation and occurrence frequency. Statistical gait analysis (SGA), a recent methodology performing a statistical characterization of gait by averaging spatio-temporal and EMG-based parameters over numerous strides, was performed in twenty-four healthy young adults. Co-contractions were assessed as the period of overlap between activation intervals of TA and GL. Results showed that GL and TA act as pure agonist/antagonists for ankle plantar/dorsiflexion (no co-contractions) in only 21.3 ± 8.2% of strides. In the remaining strides, statistically significant (p < 0.05) co-contractions appear in early stance (29.2 ± 1.7%), mid-stance (32.1 ± 18.3%) and swing (62.2 ± 2.0%). This significantly increased complexity in muscle recruitment strategy beyond the activation as pure ankle plantar/dorsiflexors, suggests that co-contractions are likely functional to further physiological tasks as foot inversion, balance improvement, control of ankle stability and knee flexion. This study represents the first attempt for the development in healthy young adults of a "normality" reference frame for GL/TA co-contractions, able to include the physiological variability of the phenomenon and eliminate the confounding effect of age.
本研究旨在评估健康年轻成年人在以自我选择的速度和步频行走时，胫骨前肌（TA）和外侧腓肠肌（GL）的共同收缩情况，包括肌肉激活起止点的变异性和发生频率。对24名健康年轻成年人进行了统计步态分析（SGA），这是一种通过对多个步幅的时空参数和基于肌电图的参数进行平均来对步态进行统计表征的最新方法。共同收缩被评估为TA和GL激活间隔的重叠期。结果显示，在仅21.3±8.2%的步幅中，GL和TA在踝关节跖屈/背屈时分别作为纯粹的主动肌/拮抗肌（无共同收缩）。在其余步幅中，在站立前期（29.2±1.7%）、站立中期（32.1±18.3%）和摆动期（62.2±2.0%）出现了具有统计学意义（p<0.05）的共同收缩。这种在肌肉募集策略上明显增加的复杂性超出了作为纯粹的踝关节跖屈/背屈肌的激活，表明共同收缩可能对诸如足内翻、平衡改善、踝关节稳定性控制和膝关节屈曲等进一步的生理任务具有功能性作用。本研究首次尝试为健康年轻成年人建立GL/TA共同收缩的“正常”参考框架，该框架能够纳入该现象的生理变异性并消除年龄的混杂效应。
