Carter Dylan J, Forsyth James R, Mattock Joshua P M, Shemmell Jonathan
Neuromotor Adaptation Laboratory, Faculty of Science, Medicine, and Health, School of Medical, Indigenous, and Health Sciences, University of Wollongong, Northfields Avenue, Wollongong, 2522, NSW, Australia.
Biomechanics Research Laboratory, Faculty of Science, Medicine, and Health, School of Medical, Indigenous, and Health Sciences, University of Wollongong, Northfields Avenue, Wollongong, 2522, NSW, Australia.
Exp Brain Res. 2025 Sep 2;243(10):205. doi: 10.1007/s00221-025-07147-z.
Hand control for dexterous and strength-based tasks involves several levels of the neuromuscular system which interact to produce force. We investigated hand force, motor unit (MU) control, and intermuscular coherence in specialist-trained groups to identify how training may affect neuromuscular force control and motor neuron activity. Equal groups of ten strength-trained (rock climbers) and dexterity-trained (musicians) individuals participated. Measures of forearm muscle structure were recorded and used to normalize maximal five-finger pinch force. Several submaximal trapezoidal pinch contractions were performed while force and electromyography (EMG) were recorded, and force steadiness was calculated. Motor unit firing rates were calculated from spike trains identified by surface EMG decomposition. Intermuscular coherence was calculated between two muscles controlling the hand (the abductor pollicis brevis and flexor digitorum superificialis), providing an estimate of the common synaptic inputs to these simultaneously activated muscles. Strength-trained participants had a higher force capacity (even when normalized to muscle size) and were steadier at controlling forces. The dexterity-trained group had faster MU discharge rates in the abductor pollicis brevis muscle at moderate force levels. Measures of synaptic inputs to the motor neuron pools were inconsistent. However, the largest peaks in the beta-band were at the lowest measured force level for the dexterity-trained group, while at the highest force intensity for the strength-trained group. These findings may indicate that the neuromuscular control of hand force differs between groups with different training histories.
用于执行需要灵巧性和力量的任务的手部控制涉及神经肌肉系统的多个层次，这些层次相互作用以产生力量。我们对经过专业训练的几组人员的手部力量、运动单位（MU）控制和肌间协调性进行了研究，以确定训练如何影响神经肌肉力量控制和运动神经元活动。十名力量训练组（攀岩者）和十名灵巧性训练组（音乐家）的人员参与了研究。记录了前臂肌肉结构的测量数据，并用于将最大五指捏力标准化。在记录力量和肌电图（EMG）的同时，进行了几次次最大梯形捏力收缩，并计算了力量稳定性。通过表面肌电图分解识别出的尖峰序列计算运动单位放电率。计算了控制手部的两块肌肉（拇短展肌和指浅屈肌）之间的肌间协调性，以估计这些同时激活的肌肉的共同突触输入。力量训练组的参与者具有更高的力量能力（即使在根据肌肉大小进行标准化后），并且在控制力量方面更稳定。在中等力量水平下，灵巧性训练组的拇短展肌运动单位放电率更快。对运动神经元池的突触输入测量结果不一致。然而，β波段的最大峰值在灵巧性训练组的最低测量力量水平处，而在力量训练组的最高力量强度处。这些发现可能表明，具有不同训练经历的组之间手部力量的神经肌肉控制存在差异。
