Kronberg M, Broström L A, Németh G
Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
Clin Orthop Relat Res. 1991 Aug(269):181-92.
The aim of the present study was to analyze shoulder muscle activity in patients with generalized joint laxity and shoulder instability and to compare it with muscle activity recorded in healthy subjects from an earlier study. Electromyographic (EMG) activity was recorded from eight shoulder muscles in six patients using surface and intramuscular fine-wire electrodes. Recordings were made from the subscapularis, supraspinatus, infraspinatus, pectoralis major (sternoclavicular part), the anterior, middle, and posterior parts of the deltoid, and the latissimus dorsi. The EMG signal was low-pass filtered, full-wave rectified, and time-average. Normalization of the EMG allowed interindividual and intraindividual comparisons. During abduction and flexion, muscle activity in the anterior and middle parts of the deltoid was significantly decreased in the patients, and during internal rotation activity in the subscapularis was increased. As in healthy subjects, patients showed simultaneous activity in both those muscles producing the movement and in the antagonistic muscles. The altered muscle activity observed in patients with generalized joint laxity provides (1) a basis for understanding the mechanism of their shoulder instability and (2) the rationale for a physical training program for these patients.
本研究的目的是分析全身关节松弛和肩关节不稳定患者的肩部肌肉活动，并将其与早期研究中健康受试者记录的肌肉活动进行比较。使用表面电极和肌内细丝电极记录了6例患者8块肩部肌肉的肌电图（EMG）活动。记录部位包括肩胛下肌、冈上肌、冈下肌、胸大肌（胸锁部）、三角肌前、中、后部以及背阔肌。对EMG信号进行低通滤波、全波整流和时间平均处理。EMG的标准化处理允许进行个体间和个体内比较。在外展和屈曲过程中，患者三角肌前、中部的肌肉活动显著降低，而在肩胛下肌内旋活动过程中其活动增加。与健康受试者一样，患者在产生运动的肌肉和拮抗肌中均表现出同步活动。全身关节松弛患者中观察到的肌肉活动改变为（1）理解其肩关节不稳定的机制提供了依据，（2）也为这些患者的体能训练计划提供了理论基础。
