Niebuhr B R
School of Allied Health Sciences, University of Texas Medical Branch at Galveston, USA.
Electromyogr Clin Neurophysiol. 1996 Mar;36(2):113-20.
The purpose was to determine if the surface electromyogram (EMG) would allow detection of submaximal grip exertions of variable effort. Fifteen healthy subjects were instructed on different trials to give maximal 100% efforts, fixed 50% submaximal efforts, or submaximal efforts of variable amount (30, 40, 50 or 70%) 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 was the finding that the variable effort condition yielded a bell-shaped force curve, similar to that produced by patients with true injuries. The key finding was that 100% and 50% exertions yielded linear EMG amplitude curves whereas the variable-effort exertion yielded a bell-shaped or quadratic curve. Thus, the EMG did allow for detection of the variable submaximal effort. However, the 100% and 50% exertions could not be distinguished by the average sustained force/peak force ratio. The EMG has the potential of being a valuable adjunct for the clinician needing to determine if a patient is feigning loss of grip strength.
目的是确定表面肌电图（EMG）是否能够检测出不同力度的次最大握力。15名健康受试者在不同试验中被要求用右手分别使出最大100%的力量、固定的50%次最大力量或不同程度（30%、40%、50%或70%）的次最大力量。在Jamar测力计的五个手柄位置对受试者进行测试。获取右手掌长肌/桡侧腕屈肌的表面肌电图。与之前的研究一致的是，不同力度条件下产生了一条钟形力曲线，类似于真正受伤患者产生的曲线。关键发现是，100%和50%的用力产生线性肌电图幅度曲线，而不同力度的用力产生钟形或二次曲线。因此，肌电图确实能够检测出不同的次最大用力。然而，通过平均持续力/峰值力比值无法区分100%和50%的用力。对于需要确定患者是否假装握力丧失的临床医生而言，肌电图有可能成为一项有价值的辅助手段。
