Fatigue-induced glenohumeral and scapulothoracic kinematic variability: Implications for subacromial space reduction

摘要: Superior humeral head translation and scapula reorientation can reduce the subacromial space. While these kinematic abnormalities exist in injured populations, effect of muscle fatigue is unclear. Additionally, mechanisms were typically studied independently, thereby neglecting potential covariance. This research evaluated influence upper extremity on glenohumeral scapulothoracic kinematics defined their relationship. Radiography motion tracking systems captured relationships, during plane elevation, both before after fatigue. Fatigue-induced changes position, scapular orientation minimum space width measured. High inter-subject variability existed for each measure which precluded identification mean differences at population level. However, significant upward rotation occurred following (p=0.0002). Despite similar results, between 39% 57% participants exhibited fatigue-related disadvantageous orientations. correlations measures generally fair (0.21-0.40) highly dependent likely attributed to variable responses. Overall, data confirms that fatigue-induced poses risk impingement syndrome across individuals. Thus, solely considering "average" or response underestimates potentially injurious consequences.