Document Type : Original Articles


1 Department of Sports Injuries and Corrective Exercises, Kish International Campus, University of Tehran, Kish Island, Iran.

2 Department of Sports Injuries and Corrective Exercises, Faculty of Physical Education and Sport Medicines, University of Tehran, Tehran, Iran.

3 Department of Sport Biomechanics, Faculty of Physical Education and Sport Medicines, University of Guilan, Rasht, Iran


Background: Shoulder joint function and the athletic performance of overheadathletes are influenced by scapular dyskinesis (SD) due to its high prevalenceamong these athletes and the motor interaction between the scapula and the arm.The present study investigated the prediction of SD through the electromyographicindices of scapulothoracic muscles in female overhead athletes.Methods: The present descriptive-correlational study was carried out on 60female volleyball, handball, basketball, and badminton athletes. The lateralscapular slide test was used to examine their SD. The required electromyographyand electrogoniometry data was recorded simultaneously to measure the activityand onset time of scapulothoracic muscles, including upper trapezius (UT),lower trapezius (LT), and serratus anterior (SA). The collected data was analyzedusing Spearman correlation and multiple regression tests.Results: Significant correlations were found between all electromyographicvariables and SD (P<0.01). The regression effects of all predictive variables on SDwere significant (P=0.001). In terms of predictive power, UT/SA co-contraction(β=0.765), UT/LT co-contraction (β=0.716), LT onset time (β=0.672), LT activity(β=0.612), and SA onset time (β=0.576) had the highest regression effects onSD, respectively. The analysis of the study model showed that there was a strongcorrelation (r=0.694) between the predictive variables and SD and that theindependent variables predicted 48% of the variance.Conclusion: The presence of imbalance in the scapulothoracic muscles ofoverhead athletes with SD indicates that athletes should be monitored bycoaches, physiotherapists, and physicians for SD screening. It is also necessaryto carry out prospective studies to examine and explore other variables relatedto SD.


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