Ballantyne B T, O'Hare S J, Paschall J L, Pavia-Smith M M, Pitz A M, Gillon J F, Soderberg G L
Physical Therapy Graduate Program, University of Iowa, Iowa City 52242-1008.
Phys Ther. 1993 Oct;73(10):668-77; discussion 677-82. doi: 10.1093/ptj/73.10.668.
The purpose of this study was to evaluate and compare the muscle activity of the supraspinatus, infraspinatus, teres minor, and lower trapezius muscles during commonly prescribed therapeutic exercises in subjects with and without shoulder pathology.
Twenty healthy subjects (9 male, 11 female) and 20 subjects with recurrent unilateral shoulder pain and weakness (14 male, 6 female), aged 18 to 40 years (mean = 28, SD = 5.8), participated in this study.
Subjects performed each of the following exercises using a hand-held weight: prone lateral (external) rotation, sidelying lateral rotation, and arm elevation in the scapular plane. Indwelling fine-wire electrodes recorded electromyographic (EMG) activity during each exercise. The EMG activity in five phases of concentric contraction of each exercise was averaged and divided into three equal time intervals. Mean EMG values normalized to maximal activity for the entire phase of concentric contraction and for each of the three intervals were used in subsequent analyses.
Two-way repeated-measures analyses of variance (ANOVAs) revealed between-group differences only in the prone lateral rotation exercise. Compared with subjects without shoulder pathology, subjects with shoulder pain showed significantly greater EMG activity in the infraspinatus muscle and less activity in the supraspinatus muscle during this exercise.
These results suggest that the pattern of muscle activation during specific shoulder movements in patients with shoulder pain may be related to pathology. Future studies are needed to determine whether an imbalance in neuromuscular control is a factor contributing directly to shoulder dysfunction or whether such an imbalance is secondary to some pathology.
本研究旨在评估和比较在进行常用治疗性锻炼时，有和没有肩部病变的受试者的冈上肌、冈下肌、小圆肌和下斜方肌的肌肉活动。
20名健康受试者（9名男性，11名女性）和20名有复发性单侧肩部疼痛和无力的受试者（14名男性，6名女性），年龄在18至40岁之间（平均 = 28，标准差 = 5.8），参与了本研究。
受试者使用手持重物进行以下每项锻炼：俯卧位侧（外）旋、侧卧位侧旋以及在肩胛平面内的手臂抬高。在每项锻炼过程中，通过植入的细针电极记录肌电图（EMG）活动。对每项锻炼的同心收缩五个阶段的EMG活动进行平均，并分为三个相等的时间间隔。将平均EMG值标准化为同心收缩整个阶段以及三个间隔中每个间隔的最大活动值，用于后续分析。
双向重复测量方差分析（ANOVA）显示，仅在俯卧位侧旋锻炼中存在组间差异。与没有肩部病变的受试者相比，肩部疼痛的受试者在该锻炼过程中冈下肌的EMG活动明显更大，而冈上肌的活动更少。
这些结果表明，肩部疼痛患者在特定肩部运动期间的肌肉激活模式可能与病变有关。需要进一步的研究来确定神经肌肉控制的不平衡是否是直接导致肩部功能障碍的因素，或者这种不平衡是否是某些病变的继发结果。
