Abstract：
The role of scapular dyskinesis as a risk factor of shoulder injury has been largely discussed. However, most studies have focused on symptomatic patients and less is known on the asymptomatic dyskinetic scapula. Removing the confounding effects of the pathologies could contribute to better characterize the scapula dyskinesis. As muscle properties (strength, fatigue, nerve injury …) have been identified as causative factors of scapular dyskinesis, this study focuses specifically on characterizing the protractor and retractor muscles of the dyskinetic scapula. Thirteen asymptomatic dyskinetic volunteers were compared to eleven asymptomatic non-dyskinetic control volunteers. Muscle characteristics were evaluated in terms of maximal strength, fatigue resistance and electromyographic activity during a functional closed-chained task. The results did not identify kinematic or muscle activity significant differences between the dyskinetic and the control group even in fatigue conditions. However, the results demonstrated that protractors vs. retractors fatigue resistance ratios were imbalanced (<0.8) in the dyskinetic group and significantly lower than in the non-dyskinetic one. Our study suggests that that strength imbalances are not necessarily related to the presence of pain at the shoulder joint. These results demonstrated the importance to complete the clinical assessments of the scapula with strength evaluations even for asymptomatic sport practitioners.
摘要：
肩胛骨损伤作为肩关节损伤的危险因素的作用已得到广泛讨论。然而,大多数研究集中在有症状的患者，而对无症状的运动障碍的肩胛骨的了解较少。消除病理的混杂作用可能有助于更好地表征肩胛骨发育不良。作为肌肉特性(力量，疲劳,神经损伤...)已被确定为肩胛骨发育不良的致病因素，这项研究特别集中在表征运动障碍肩胛骨的量角器和牵开器肌肉。将13名无症状的运动障碍志愿者与11名无症状的非运动障碍对照志愿者进行了比较。根据最大力量评估肌肉特征，功能性闭链任务期间的抗疲劳性和肌电图活动。即使在疲劳条件下，结果也未发现运动障碍组和对照组之间的运动学或肌肉活动显着差异。然而,结果表明，量角器与运动障碍组的牵开器抗疲劳率不平衡(<0.8),显著低于非运动障碍组.我们的研究表明，力量失衡不一定与肩关节疼痛的存在有关。这些结果表明，即使对于无症状的运动从业者，也必须通过强度评估来完成肩胛骨的临床评估。
