Abstract

Rotator cuff tendinopathy (RCT), a common shoulder disorder in overhead sports, has different presentation patterns. The presentation mode may help identify altered biomechanics, a common cause of impingement of the rotator cuff tendon. Therefore, this study investigated the patterns of presentation of RCT and their association with selected biomechanical variables in overhead sport athletes. This cross-sectional study involved 135 (95 males and 40 females) recreational overhead sport athletes between the ages of 19 to 39 years recruited by convenience. RCT was assessed using musculoskeletal ultrasonography and specific clinical tests. Posterior shoulder tightness (PST), pectoralis minor muscle length (PMML) and scapular asymmetry were evaluated. Data were analyzed using mean, frequency, standard deviation, Kruskal-Wallis, ANOVA and Chi-square. Participants designated as the control group had neither clinical symptoms nor abnormal ultrasonography. The patterns of presentation identified among the other participants included clinical symptoms only, abnormal ultrasonography findings only and a combination of both.  Compared with the control group, participants with only abnormal ultrasonography showed no significant (p > 0.05) differences in biomechanical variables. In contrast, those in the other groups had shoulder tightness and severely compromised PMML (PST:p = 0.01)  PMML: p = 0.01). However, there was no significant (p = 0.13) association between scapular asymmetry and RCT in all the groups. Abnormal ultrasonography of the rotator cuff tendon in the absence of clinical symptoms is an early indicator of RCT.

Key words: Rotator cuff tendinopathy, pectoralis minor muscle length, shoulder tightness, kinematics, overhead sports.