Castronovo Anna Margherita, De Marchis Cristiano, Schmid Maurizio, Conforto Silvia, Severini Giacomo
Department of Bioengineering, Imperial College London, London SW7 2AZ, UK.
School of Electrical & Electronic Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
Appl Bionics Biomech. 2018 Jun 3;2018:4759232. doi: 10.1155/2018/4759232. eCollection 2018.
The term "task failure" describes the point when a person is not able to maintain the level of force required by a task. As task failure approaches, the corticospinal command to the muscles increases to maintain the required level of force in the face of a decreased mechanical efficacy. Nevertheless, most motor tasks require the synergistic recruitment of several muscles. How this recruitment is affected by approaching task failure is still not clear. The increase in the corticospinal drive could be due to an increase in synergistic recruitment or to overlapping commands sent to the muscles individually. Herein, we investigated these possibilities by combining intermuscular coherence and synergy analysis on signals recorded from three muscles of the quadriceps during dynamic leg extension tasks. We employed muscle synergy analysis to investigate changes in the coactivation of the muscles. Three different measures of coherence were used. Pooled coherence was used to estimate the command synchronous to all three muscles, pairwise coherence the command shared across muscle pairs and residual coherence the command peculiar to each couple of muscles. Our analysis highlights an overall decrease in synergistic command at task failure and an intensification of the contribution of the nonsynergistic shared command.
术语“任务失败”描述的是一个人无法维持任务所需力量水平的时刻。随着任务失败的临近，对肌肉的皮质脊髓指令会增加，以便在机械效能下降的情况下维持所需的力量水平。然而，大多数运动任务需要协同募集几块肌肉。接近任务失败时这种募集是如何受到影响的仍不清楚。皮质脊髓驱动的增加可能是由于协同募集的增加，或者是单独发送给肌肉的重叠指令。在此，我们通过对动态腿部伸展任务期间股四头肌三块肌肉记录的信号进行肌间相干性和协同分析相结合的方法来研究这些可能性。我们采用肌肉协同分析来研究肌肉共同激活的变化。使用了三种不同的相干性测量方法。合并相干性用于估计与所有三块肌肉同步的指令，成对相干性用于估计跨肌肉对共享的指令，残余相干性用于估计每对肌肉特有的指令。我们的分析突出了任务失败时协同指令的总体下降以及非协同共享指令贡献的增强。
