Santos Marcio J, Belangero William Dias, Almeida Gil L
Physical Therapy Department, Universidade de Ribeirão Preto, SP, Brazil.
J Electromyogr Kinesiol. 2007 Apr;17(2):167-75. doi: 10.1016/j.jelekin.2006.01.010. Epub 2006 Mar 20.
Several shoulder dysfunctions are generally characterized as Shoulder Impingement Syndrome (SIS). Specifically, glenohumeral instability (GI) has been viewed as a primary cause of SIS in young individuals, mainly in overhead athletics. Past studies have associated GI with modifications in latency, recruitment order and/or EMG activity. However, it is not clear if pain and/or joint instability can account for these observed changes. The aim of this investigation was to analyze the effect of glenohumeral instability on the latencies and recruitment order of the superficial muscles of the glenohumeral and scapulothoracic joints in swimmers without pain symptom. Eight individuals with and eight without history of Shoulder Impingement Syndrome performed bilateral and simultaneous shoulder elevations at three different distances. The shoulder kinematics and EMG activities of glenohumeral and scapulothoracic muscles were registered. Results showed that subjects of both groups performed the task with similar latencies and recruitment order of the muscle activities. We conclude that shoulder instability does not necessarily affect the latencies and recruitment order of the shoulder muscles during the elevation of the shoulder in the scapular plane. Pain and other factors may be involved in the kinematics and electromyographic alterations demonstrated in other experiments.
几种肩部功能障碍通常被归类为肩部撞击综合征（SIS）。具体而言，盂肱关节不稳定（GI）被视为年轻个体中SIS的主要原因，主要发生在从事过头运动的人群中。过去的研究将GI与潜伏期、募集顺序和/或肌电图活动的改变联系起来。然而，尚不清楚疼痛和/或关节不稳定是否可以解释这些观察到的变化。本研究的目的是分析盂肱关节不稳定对无疼痛症状的游泳运动员盂肱关节和肩胛胸壁关节表层肌肉的潜伏期和募集顺序的影响。八名有肩部撞击综合征病史的人和八名无该病史的人在三个不同距离进行双侧同时肩部抬高动作。记录了盂肱关节和肩胛胸壁肌肉的肩部运动学和肌电图活动。结果表明，两组受试者在肌肉活动的潜伏期和募集顺序方面完成任务的情况相似。我们得出结论，在肩胛平面内肩部抬高过程中，肩部不稳定不一定会影响肩部肌肉的潜伏期和募集顺序。疼痛和其他因素可能与其他实验中显示的运动学和肌电图改变有关。
