Wadsworth D J, Bullock-Saxton J E
University of Queensland, Department of Physiotherapy, Brisbane, Australia.
Int J Sports Med. 1997 Nov;18(8):618-24. doi: 10.1055/s-2007-972692.
Athletes with shoulder pathology consistently demonstrate abnormalities in scapular rotator activity, suggesting that muscle dysfunction is a factor to consider in the aetiology or recurrence of shoulder pain. However, one important measure of the coordinated activity between the scapular rotators, their timing or temporal recruitment pattern, remains undetermined. The purposes of this study were to 1. provide normative data on the temporal recruitment pattern of the scapular rotators in freestyle swimmers, 2. determine the effect of a unilateral shoulder injury on this pattern, 3. determine whether these effects extend to the non-injured side, and 4. determine the effect of injury on the consistency (variability) of muscle recruitment. Surface EMG data for the upper and lower trapezius and serratus anterior were recorded bilaterally from two groups of competitive freestyle swimmers during controlled bilateral elevation in the plane of the scapula. An injured group comprising nine swimmers with unilateral shoulder pathology and a control group of nine non-injured swimmers were included. Temporal data determined for the onset of muscle activation for each muscle were then compared between groups using an ANOVA and a one-sided F test. The results of the study indicate that in non-injured swimmers, upper trapezius is activated 217 ms prior to shoulder motion, followed by serratus anterior activation 53 ms after motion commences. Lower trapezius was not recruited until 349 ms after shoulder motion, when the arm had attained 15 degrees elevation. In injured swimmers, all three muscles on the injured side displayed significantly increased variability in the timing of activation (p < 0.05), whilst the serratus anterior was significantly delayed in its activation on the non-injured side (p < 0.05). Skill hand preference was shown to have no effect on muscle recruitment. The findings of this study indicate that a relationship does exist between shoulder injury and the temporal recruitment patterns of the scapular rotators, such that injury reduces the consistency of muscle recruitment. They further suggest that injured subjects have muscle function deficits on their unaffected side.
患有肩部疾病的运动员始终表现出肩胛旋转肌活动异常，这表明肌肉功能障碍是肩部疼痛病因或复发中需要考虑的一个因素。然而，肩胛旋转肌之间协调活动的一个重要指标，即它们的时间或时间募集模式，仍未确定。本研究的目的是：1. 提供自由泳运动员肩胛旋转肌时间募集模式的规范数据；2. 确定单侧肩部损伤对该模式的影响；3. 确定这些影响是否扩展到未受伤侧；4. 确定损伤对肌肉募集一致性（变异性）的影响。在肩胛骨平面进行双侧控制性抬高时，从两组竞技自由泳运动员双侧记录斜方肌上下部和前锯肌的表面肌电图数据。其中包括一个由九名患有单侧肩部疾病的游泳运动员组成的受伤组和一个由九名未受伤游泳运动员组成的对照组。然后使用方差分析和单侧F检验比较两组之间为每块肌肉确定的肌肉激活起始时间数据。研究结果表明，在未受伤的游泳运动员中，斜方肌上部在肩部运动前217毫秒被激活，随后前锯肌在运动开始后53毫秒被激活。直到肩部运动后349毫秒，当手臂抬高到15度时，下斜方肌才开始募集。在受伤的游泳运动员中，受伤侧的所有三块肌肉在激活时间上均表现出显著增加的变异性（p<0.05），而前锯肌在未受伤侧的激活明显延迟（p<0.05）。结果显示，优势手对肌肉募集没有影响。本研究结果表明，肩部损伤与肩胛旋转肌的时间募集模式之间确实存在关联，即损伤会降低肌肉募集的一致性。研究还进一步表明，受伤受试者未受影响一侧存在肌肉功能缺陷。
