In current rehabilitation practice, exercise selection is commonly based on the amount of muscle recruitment demonstrated by electromyographic (EMG) analysis. A preponderance of evidence supports the concept that EMG of a muscle and torque output are positively correlated. This study was designed to investigate the relationship between surface EMG activity of the infraspinatus and torque production during exercises involving shoulder external rotation (ER). A total of 30 participants (average age = 24.6 y) performed maximum voluntary isometric contraction of ER at 5 points within the range of motion of 3 shoulder exercise positions with concomitant surface EMG recording. As a maximal internally rotated position was approached, maximum ER torque and minimum or near-minimum EMG recruitment were demonstrated. Conversely, at maximally externally rotated positions, EMG activity was greatest and torque values were lowest. An inverse relationship between joint torque output and EMG activity was established in each of the 3 exercises. The inverse relationship between EMG activity and torque output during Shoulder ER suggests that there may be additional factors warranting consideration during exercise selection. Further research may be needed to determine the relative value of electrical activity versus torque output to optimize the selection of rehabilitative exercises.

在当前的康复实践中，运动选择通常基于肌电图（EMG）分析显示的肌肉募集量。大量证据支持肌肉肌电图和扭矩输出呈正相关的概念。本研究旨在研究肩部外旋 (ER) 运动期间冈下肌表面肌电图活动与扭矩产生之间的关系。共有 30 名参与者（平均年龄 = 24.6 岁）在 3 个肩部运动位置的运动范围内的 5 个点进行 ER 最大自主等长收缩，并进行表面肌电图记录。当接近最大内旋转位置时，表现出最大 ER 扭矩和最小或接近最小 EMG 募集。相反，在最大外旋位置，肌电图活动最大，扭矩值最低。在这 3 个练习中，关节扭矩输出和 EMG 活动之间都建立了反比关系。肩部 ER 期间肌电图活动与扭矩输出之间的反比关系表明，在运动选择过程中可能还需要考虑其他因素。可能需要进一步的研究来确定电活动与扭矩输出的相对值，以优化康复练习的选择。