Yang Ningjia, Li Xuesi, An Qi, Li Jingsong, Shimoda Shingo
IEEE Trans Neural Syst Rehabil Eng. 2025;33:1381-1391. doi: 10.1109/TNSRE.2025.3557777. Epub 2025 Apr 16.
The coordination of muscles in human locomotion is commonly understood as the integration of motor modules known as muscle synergies. Recent research has delved into the adaptation of muscle synergies during the acquisition of new motor skills. However, the precise interplay between modulated muscle synergies during movement according to motion requirements remains unclear. Here, we aim to elucidate the alterations in locomotor synergies across various lower-limb motion strategies and motor tasks. Our findings reveal consistent weights of muscles in muscle synergies alongside varying timing activation aligned with specific motion requirements. It shows that spatial muscle synergies remain stable across different motor tasks, but humans adjusted the timing activation of these modules (temporal muscle synergies) to meet the motor requirements. To classify temporal muscle synergies and quantify connection weights for both self-connections and connections between muscle synergies, we employed a graph neural network. Our results demonstrate that muscle synergy 4, responsible for elevating the thigh to propel forward during the swing phase, experiences pronounced enhancement with changes in motion strategies. Furthermore, we observed a reduction in the self-connection of muscle synergy 2, implicated in stabilizing body posture, during motion tasks other than normal walking. Additionally, the connections between muscle synergy 2 and other synergies diminished, indicating more adaptation in muscle synergy 2 to achieve stabilization in more challenging motor tasks. The validity of these findings was verified through five-fold cross-validation, affirming the efficacy of our approach in elucidating neuro-modulation mechanisms in human locomotion. Our proposed methodology holds promising implications for the development of personalized training strategies, offering insights into the intricate interactions among different muscle synergies in accomplishing motor tasks.
人类运动中肌肉的协调通常被理解为被称为肌肉协同作用的运动模块的整合。最近的研究深入探讨了在获得新运动技能过程中肌肉协同作用的适应性。然而，根据运动需求在运动过程中调节的肌肉协同作用之间的确切相互作用仍不清楚。在这里，我们旨在阐明不同下肢运动策略和运动任务中运动协同作用的变化。我们的研究结果表明，肌肉协同作用中肌肉的权重一致，同时不同的激活时间与特定的运动需求相匹配。这表明空间肌肉协同作用在不同的运动任务中保持稳定，但人类会调整这些模块的激活时间（时间肌肉协同作用）以满足运动需求。为了对时间肌肉协同作用进行分类并量化自我连接以及肌肉协同作用之间连接的权重，我们采用了图神经网络。我们的结果表明，负责在摆动阶段抬高大腿以向前推进的肌肉协同作用4，随着运动策略的变化而显著增强。此外，我们观察到，在除正常行走之外的运动任务中，与稳定身体姿势有关的肌肉协同作用2的自我连接减少。此外，肌肉协同作用2与其他协同作用之间的连接减少，表明肌肉协同作用2在更具挑战性的运动任务中为实现稳定而有更多适应性变化。这些发现的有效性通过五折交叉验证得到了验证，证实了我们的方法在阐明人类运动中的神经调节机制方面的有效性。我们提出的方法对个性化训练策略的发展具有重要意义，为不同肌肉协同作用在完成运动任务中的复杂相互作用提供了见解。
