Niebuhr B R, Marion R, Hasson S M
University of Texas Medical Branch, Galveston.
Electromyogr Clin Neurophysiol. 1993 Apr-May;33(3):149-56.
The purpose of the present research was to investigate the use of surface EMG in assessing effort while measuring grip strength with the Jamar dynamometer. We hypothesized that sincere, maximal grip contractions could be distinguished from feigned, submaximal contractions by differences in the amplitude and frequency content of the EMG, as well as by differences in force. Healthy subjects (seven men and ten women) were instructed on different trials to give a sincere (maximal, 100%) effort or a feigned (50% of maximal) effort with the right hand. The subjects were tested at each of the five handle positions of the Jamar dynamometer. Surface EMG was obtained for the right palmaris longus/flexor carpi radialis muscles. Consistent with previous research, we found that the 50% efforts, compared to 100% efforts, showed, (1) lower peak force; (2) a slower rise to peak force; and (3) a different pattern of force measurements as a function of handle position. Feigned and sincere efforts also differed in the EMG. As hypothesized, amplitude was lower for 50% than 100% efforts. The frequency spectra of the EMG were obtained by Fourier analysis. The 50% efforts showed a higher frequency EMG than did the 100%. The results supported the hypothesis that surface EMG may provide a measure of effort in a grip strength task. Analysis of the EMG, in conjunction with force analysis, has the potential of being a valuable tool for the clinician needing to determine whether a patient is giving a sincere, maximal effort or is feigning.
本研究的目的是在使用贾马尔握力计测量握力时，研究表面肌电图在评估用力程度方面的应用。我们假设，通过肌电图的幅度和频率成分差异以及力量差异，可以区分真诚的最大握力收缩和假装的次最大收缩。健康受试者（7名男性和10名女性）在不同试验中被要求用右手给出真诚的（最大，100%）用力或假装的（最大用力的50%）用力。在贾马尔握力计的五个手柄位置分别对受试者进行测试。获取右手掌长肌/桡侧腕屈肌的表面肌电图。与先前的研究一致，我们发现，与100%用力相比，50%用力表现为：（1）峰值力较低；（2）达到峰值力的上升速度较慢；（3）作为手柄位置函数的力测量模式不同。假装用力和真诚用力在肌电图方面也存在差异。如假设的那样，50%用力的幅度低于100%用力。通过傅里叶分析获得肌电图的频谱。50%用力的肌电图频率高于100%用力。结果支持了表面肌电图可能为握力任务中的用力程度提供一种测量方法的假设。肌电图分析与力量分析相结合，有可能成为临床医生确定患者是在真诚地、最大程度地用力还是在假装用力的有价值工具。
