Aarhus University, Denmark.
Odense University Hospital, Denmark.
Neurorehabil Neural Repair. 2021 Jul;35(7):644-653. doi: 10.1177/15459683211017502. Epub 2021 May 22.
Motor fatigability (i.e. contraction-induced reduction in muscle strength) from a concentric task associate stronger to walking and perception of fatigue in persons with multiple sclerosis (pwMS), compared with an isometric task. However, the central and peripheral contributions of motor fatigability between these tasks have not been investigated.
Compare the central and peripheral contributions of motor fatigability in the knee extensors in a sustained isometric fatigability protocol versus a concentric fatigability protocol and in pwMS versus healthy controls (HCs).
Participants (n=31 pwMS; n=15 HCs) underwent neuromuscular testing before and immediately after two knee extensor fatigability tasks (sustained isometric and concentric) in an isokinetic dynamometer. Neuromuscular testing of fatigability consisted of maximal voluntary contraction, voluntary activation (central/neural contributor), and resting twitch (peripheral/muscular contributor) determined by the interpolated twitch technique.
Sustained isometric and concentric fatigability protocols resulted in motor fatigability for both pwMS and HCs, with no between-protocols differences for either group. Regression analysis showed that motor fatigability variance in pwMS was mainly attributed to central fatigability in the sustained isometric protocol and to both central and peripheral fatigability in the concentric protocol. In HCs, the variance in sustained isometric and concentric fatigability were attributed to both peripheral and central fatigability.
Central and peripheral contributions of motor fatigability differed between sustained isometric and concentric protocols as well as between pwMS and HCs. These between-protocol differences in pwMS provide a neuromuscular dimension to the reported difference in the strength of associations of concentric and isometric tasks to walking and perception of fatigue in pwMS.
与等长任务相比，在多发性硬化症（pwMS）患者中，离心任务引起的运动疲劳（即收缩引起的肌肉力量下降）与步行和疲劳感的相关性更强。然而，在这些任务之间，运动疲劳的中枢和外周贡献尚未得到研究。
比较在持续等长疲劳协议与离心疲劳协议中，膝关节伸肌的运动疲劳的中枢和外周贡献在 pwMS 与健康对照（HCs）之间的差异。
参与者（n=31 名 pwMS；n=15 名 HCs）在等速测力计上进行了两次膝关节伸肌疲劳任务（持续等长和离心）前后的神经肌肉测试。疲劳的神经肌肉测试包括最大自主收缩、自愿激活（中枢/神经贡献者）和通过插值抽搐技术确定的静息抽搐（外周/肌肉贡献者）。
持续等长和离心疲劳协议导致了 pwMS 和 HCs 的运动疲劳，两组之间没有协议之间的差异。回归分析表明，pwMS 的运动疲劳方差主要归因于持续等长协议中的中枢疲劳，以及离心协议中的中枢和外周疲劳。在 HCs 中，持续等长和离心疲劳的方差归因于外周和中枢疲劳。
运动疲劳的中枢和外周贡献在持续等长和离心协议之间以及 pwMS 和 HCs 之间存在差异。这些 pwMS 之间的协议差异为报告的离心和等长任务与 pwMS 的步行和疲劳感之间的关联强度差异提供了神经肌肉维度。
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