Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
J Electromyogr Kinesiol. 2011 Feb;21(1):59-66. doi: 10.1016/j.jelekin.2010.06.006.
The present study examined various biomechanical parameters in symptomatic and asymptomatic computer users during mouse-clicking tasks with different speed and precision demands. Surface electromyography (EMG) of right wrist flexors and extensors were compared between individuals with computer-related wrist/hand symptoms (n=9) and pain-free controls (n=8). Each subject performed four mouse tasks with high and low precision, constant and fastest speed of 5 min each. Results showed that Case subjects recorded significantly lower EMG amplitudes during maximum voluntary contractions in three out of four forearm muscles (p=0.001-0.019). Normalised median amplitudes of extensor carpi radialis and flexor carpi ulnaris showed significant differences between groups in the speed conditions (p=0.01, 0.04, respectively). Case subjects reported significant discomforts in the wrist/hand region in all tasks, while recorded significantly longer response time and fewer mouse clicks compared to controls. Results suggested that forearm muscles in symptomatic individuals were inhibited in their maximal activation as well as during functional tasks, and this may imply altered motor control mechanisms in forearm muscles contributing to work-related musculoskeletal disorders.
本研究在不同速度和精度要求的鼠标点击任务中，检查了有症状和无症状的计算机使用者的各种生物力学参数。对有计算机相关手腕/手部症状的个体（n=9）和无疼痛对照组（n=8）的右手腕屈肌和伸肌的表面肌电图（EMG）进行了比较。每位受试者进行了四项鼠标任务，每项任务的精度和速度分别为高和低，持续时间为 5 分钟。结果表明，在四项前臂肌肉中的三项中，病例组在最大自主收缩期间记录到的 EMG 幅度明显较低（p=0.001-0.019）。在速度条件下，桡侧腕屈肌和尺侧腕屈肌的正常化中位数幅度在组间存在显著差异（p=0.01，0.04）。病例组在所有任务中均报告手腕/手部区域有明显不适，而与对照组相比，记录到的反应时间明显更长，鼠标点击次数更少。结果表明，症状个体的前臂肌肉在最大激活以及在功能任务中受到抑制，这可能意味着前臂肌肉的运动控制机制发生改变，导致与工作相关的肌肉骨骼疾病。
