Ceriello Imma, Ghislieri Marco, Rum Lorenzo, Camomilla Valentina, Macaluso Andrea, Borzuola Riccardo
Laboratory of Bioengineering and Neuromechanics, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy.
Interuniversity Centre of Bioengineering of the Human Neuromusculoskeletal System, University of Rome "Foro Italico", Rome, Italy.
Eur J Appl Physiol. 2025 Aug 27. doi: 10.1007/s00421-025-05951-7.
Understanding the neuromuscular strategies underlying postural stability is crucial for evaluating motor control and balance. This study examines muscle coordination during several variations of the Functional Reach (FR)-unilateral Functional Reach (uniFR), bilateral Functional Reach (biFR), and Lateral Reach (LR)-in healthy young adults. This study aims to establish a reference baseline for these tasks and assess whether fundamental motor control strategies are preserved across FR variations, despite distinct biomechanical demands and directional stability components.
Seventeen healthy young adults performed ten repetitions for each FR task. Muscle synergies were derived using non-negative matrix factorization on surface electromyography (EMG) data recorded from eight muscles on each side of the body.
Results revealed that fewer synergies were required for anterior-posterior stability (uniFR and biFR), while medial-lateral control entailed in LR required an additional synergy. Despite the directional tuning of muscle contributions, both anterior-posterior and medial-lateral balance control relied on similar underlying motor functions, thus engaging the same muscle synergies in varying combinations. Furthermore, a greater similarity in muscle synergy structure and robustness was observed between uniFR and biFR compared to LR, suggesting a shared neural control strategy. Moreover, the LR task exhibited higher variability, reflecting a more complex and less standardized motor control process.
Our findings indicate that similar motor functions are recruited across different balance tasks, with directionally tuned muscle synergies. This offers a deeper insight into the muscle coordination strategies during reaching tasks, providing a novel framework for evaluating the effects of aging or pathological conditions on neuromuscular control.
了解姿势稳定性背后的神经肌肉策略对于评估运动控制和平衡至关重要。本研究考察了健康年轻成年人在功能性伸展（FR）的几种变体——单侧功能性伸展（uniFR）、双侧功能性伸展（biFR）和侧方伸展（LR）过程中的肌肉协调情况。本研究旨在为这些任务建立一个参考基线，并评估尽管存在不同的生物力学需求和方向稳定性成分，但基本运动控制策略在FR变体中是否得以保留。
17名健康年轻成年人对每个FR任务进行10次重复。使用非负矩阵分解从身体每侧的八块肌肉记录的表面肌电图（EMG）数据中提取肌肉协同作用。
结果显示，前后稳定性（uniFR和biFR）所需的协同作用较少，而LR中涉及的内外侧控制需要额外的协同作用。尽管肌肉贡献存在方向调整，但前后平衡控制和内外侧平衡控制都依赖于相似的潜在运动功能，因此以不同组合使用相同的肌肉协同作用。此外，与LR相比，uniFR和biFR之间在肌肉协同结构和稳健性方面观察到更大的相似性，表明存在共同的神经控制策略。而且，LR任务表现出更高的变异性，反映出更复杂且标准化程度更低的运动控制过程。
我们的研究结果表明，在不同的平衡任务中会调用相似的运动功能，且肌肉协同作用存在方向调整。这为深入了解伸展任务期间的肌肉协调策略提供了见解，为评估衰老或病理状况对神经肌肉控制的影响提供了一个新框架。
