Department of Clinical and Experimental Sciences, Research Centre for Neuromuscular Function and Adapted Physical Activity "Teresa Camplani", Università degli Studi di Brescia, Brescia, Italy.
Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK.
J Electromyogr Kinesiol. 2020 Dec;55:102472. doi: 10.1016/j.jelekin.2020.102472. Epub 2020 Sep 18.
Acute changes in central control and peripheral properties of motor units following a half-marathon has never been examined in master athletes. Therefore, the main purpose of this study was to estimate the firing properties and twitch characteristics of motor units after a 21-km race in a group of ten trained older adults. High-density surface EMG decomposition was used to identify motor unit activity during a submaximal contraction of the tibialis anterior muscle before and after the half marathon. The area of the estimated motor unit twitch profile was found smaller after the race (P = 0.039). This reduction in contractile efficiency was compensated by a significant increase in the initial and average discharge rate of the identified motor units (P < 0.001). By estimating the amount of shared and independent synaptic input to tibialis anterior motor neurons, we demonstrated that adaptations in the discharge properties of master athletes' motor units are the likely consequence of an increased net excitatory synaptic drive to the motor neuron pool. These findings suggest a potential role of long-distance running in ameliorating declines in muscle function of older adults by enhancing the neural drive to muscle.
在精英运动员中，从未研究过半马拉松后中枢控制和运动单位外周特性的急性变化。因此，本研究的主要目的是估计在一组经过训练的老年成年人进行 21 公里比赛后运动单位的放电特性和抽搐特征。高密度表面肌电图分解用于在半程马拉松前后识别胫骨前肌的亚最大收缩期间的运动单位活动。比赛后发现估计的运动单位抽搐轮廓的面积较小（P=0.039）。这种收缩效率的降低通过所识别的运动单位的初始和平均放电率的显著增加得到了补偿（P<0.001）。通过估计胫骨前运动神经元的共享和独立突触输入量，我们证明了精英运动员运动单位放电特性的适应是运动神经元池的净兴奋性突触驱动增加的可能结果。这些发现表明，长跑可能通过增强对肌肉的神经驱动，改善老年人肌肉功能的下降。
