Faculty of Frontier Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-Machi, Kanazawa, 920-1192, Japan.
Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia.
Eur J Appl Physiol. 2024 Dec;124(12):3707-3717. doi: 10.1007/s00421-024-05553-9. Epub 2024 Aug 7.
The aim of this study was to examine the effect of vibration on motor unit (MU) firing behavior and physical performance of antagonist muscles in healthy young adult males.
Fourteen males (age = 24.3 ± 3.6 years) were included in this study. There were two conditions, one in which participants received 80 Hz vibration in the distal tendon of the hamstring for 30 s and the control condition (no vibration). High-density surface electromyography (HD-SEMG) signals and maximal voluntary contraction (MVC) of knee extensor muscles were evaluated before and after the respective conditions and recorded from the vastus lateralis muscle during submaximal ramp-up and sustained contractions at 30% MVC. Convolution blind source separation was used to decompose the HD-SEMG signals into individual MU firing behaviors.
In total, 739 MUs were detected (control; 360 MUs and vibration; 379 MUs), and a total of 312 matched MUs were identified across both submaximal contraction conditions (control: 150 MUs; vibration: 162 MUs). Vibration significantly increased the discharge rate (p = 0.047) and decreased the recruitment threshold before and after intervention (p = 0.001) but not in the control condition. Furthermore, the recruitment threshold is a factor that influences discharge rate. Significant correlations were observed between the recruitment threshold and both the ∆ discharge rate and the ∆ recruitment threshold under the vibration condition (p < 0.001).
Vibration increased in the discharge rate and decreased the recruitment threshold of the antagonist muscle. These findings suggested that vibration contributes to immediate changes in the neural control of antagonist muscles.
本研究旨在探讨振动对健康年轻男性运动单位（MU）放电行为和拮抗肌物理性能的影响。
本研究纳入了 14 名男性（年龄=24.3±3.6 岁）。实验设置了两种条件，一种是在腘绳肌远端肌腱处接受 80Hz 振动 30s，另一种是对照条件（无振动）。在各自的条件前后，评估了膝关节伸肌的高密度表面肌电图（HD-SEMG）信号和最大自主收缩（MVC），并在 30%MVC 的亚最大斜坡上升和持续收缩期间从股外侧肌记录。卷积盲源分离用于将 HD-SEMG 信号分解为个体 MU 放电行为。
共检测到 739 个 MU（对照：360 个 MU，振动：379 个 MU），在两种亚最大收缩条件下共识别到 312 个匹配 MU（对照：150 个 MU，振动：162 个 MU）。振动显著增加了放电率（p=0.047），并降低了干预前后的募集阈值（p=0.001），但在对照条件下没有。此外，募集阈值是影响放电率的一个因素。在振动条件下，募集阈值与放电率的变化量（∆放电率）和募集阈值的变化量（∆募集阈值）之间存在显著相关性（p<0.001）。
振动增加了拮抗肌的放电率，降低了募集阈值。这些发现表明，振动有助于拮抗肌神经控制的即时变化。
