Abstract

The present study sought to evaluate how mental effort modulates premotor activity within forearm muscles in the context of an isometric grasping task. Muscle activity of the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC) was recorded during the application of maximum grip forces in nineteen healthy adult subjects. Each subject was examined under two experimental conditions: 1) spontaneous initiation of grasp (SI) and 2) focused concentration preceding the initiation of grasp (CA). Two novel parameters, the mean premotor duration (MPD) and the mean premotor power (MPP) were used to distinguish patterns of muscle activity. Here we tested the hypothesis was maximal grip strength is primed by muscle activity during the premotor phase. Our results demonstrate that MPD for each muscle group was significantly longer in the CA condition than for the SI condition (BF₁₀ = 491497) and that MPP was significantly greater in EDC than in FDS (BF₁₀ = 4305). Furthermore, both the MPD and MPP of the EDC were significantly correlated with maximum grip force. These results suggest that the increase of premotor activity consequent to the mental effort (focused concentration) may support internal biomechanical and physiological mechanisms which serve to enhance patterns of neuromuscular synergies.

摘要

本研究试图评估在等距抓取任务的背景下，精神努力如何调节前臂肌肉内的运动前活动。在十九名健康成人受试者中，在施加最大握力的过程中记录了浅指屈肌（FDS）和指伸伸肌（EDC）的肌肉活动。在两个实验条件下对每个受试者进行检查：1）自发开始抓握（SI）和2）集中注意力在抓握开始之前（CA）。两个新参数，平均运动前持续时间（MPD）和平均运动前功率（MPP）被用来区分肌肉活动模式。在这里，我们测试了这一假设，即在运动前阶段，最大的抓地力是由肌肉活动引起的。₁₀ = 491497），而EDC中的MPP明显高于FDS（BF ₁₀ = 4305）。此外，EDC的MPD和MPP都与最大抓地力显着相关。这些结果表明，由于精神努力（集中注意力）而导致的运动前活动的增加可能支持内部生物力学和生理学机制，这些机制可增强神经肌肉协同作用的模式。