Developmental changes in upper limb muscle synergies during throwing: A comparison between preschoolers and schoolers

IF 4.1 2区综合性期刊 Q1 MULTIDISCIPLINARY SCIENCES

iScience Pub Date : 2025-09-03 DOI:10.1016/j.isci.2025.113497

Hiroki Saito , Ayane Kusafuka , Taishi Okegawa , Saki Takao , Naotsugu Kaneko , Hikaru Yokoyama , Ken Takiyama , Kenji Takaki , Kimitaka Nakazawa

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Abstract

Throwing is a fundamental motor behavior that undergoes marked refinement during childhood, yet the neuromuscular mechanisms underlying this process remain unclear. We compared upper limb muscle synergies in preschool-aged (3–5 years; n = 13) and school-aged (6–9 years; n = 8) children during overarm throwing. Participants threw balls toward a fixed target while electromyographic activity from 16 upper limb muscles and ball kinematics were recorded. Muscle synergies, extracted using non-negative matrix factorization, were analyzed for structure and sparseness. School-aged children exhibited higher ball velocity, improved accuracy, and greater synergy sparseness, reflecting more selective muscle recruitment. Cluster analysis identified eight synergy clusters in schoolers versus six in preschoolers, with several preschooler synergies fractionated into functionally specialized components in schoolers. These refinements—across the upper limb—likely enhance energy transfer efficiency and release control. The findings highlight fractionation-driven specialization as a key developmental adaptation that supports improved throwing performance.

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投掷运动中上肢肌肉协同作用的发展变化：学龄前儿童与学龄儿童的比较

投掷是一种基本的运动行为，在儿童时期经历了显著的改进，但这一过程背后的神经肌肉机制尚不清楚。我们比较了学龄前儿童（3-5岁，n = 13）和学龄儿童（6-9岁，n = 8）的上肢肌肉协同作用。参与者向固定目标投掷球，同时记录16块上肢肌肉的肌电图活动和球的运动学。利用非负矩阵分解提取肌肉协同效应，分析其结构和稀疏性。学龄儿童表现出更高的球速、更高的准确性和更大的协同稀疏性，反映出更多的选择性肌肉招募。聚类分析确定了学龄期儿童有8个协同集群，而学龄前儿童有6个协同集群，学龄前儿童中有几个协同集群被划分为功能专门的组件。这些改进——跨越上肢——可能会提高能量传递效率和释放控制。研究结果强调，分馏驱动的专业化是支持提高投掷成绩的关键发展适应。

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来源期刊

iScience Multidisciplinary-Multidisciplinary

CiteScore

7.20

自引率

1.70%

发文量

1972

审稿时长

6 weeks

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