A Comparative Study on Kinetic Variables of the Shoulder Complex According to the History of Shoulder and Elbow Injuries in Male Amateur Baseball Players in Their 20s

Purpose: This study was performed to investigate the differences in kinetic variables of the shoulder complex, depending on the history of a shoulder and elbow injuries in male college baseball players in their 20s.Methods: A total of 35 participants participated.Shoulder function (Kerlan-Jobe Orthopedic Clinic Shoulder and Elbow [KJOC] score), range of motion (ROM) of the internal rotation (IR) and external rotation (ER), glenohumeral internal rotation deficit (GIRD), isokinetic torques of the IR and ER, scapular alignment, and isometric strength of the periscapular muscles were measured.Differences in variables between the injured and non-injured groups were analyzed, as well as correlations between variables.Results: IR ROM, eccentric ER torque, middle trapezius (MT) strength, and KJOC score were lower in the injured than the non-injured groups (p 0.05).Whereas, the GIRD, ER ROM, scapular depression angle (SDA), and upper trapezius strength were higher in the injured group (p 0.05).In addition, showed a fair positive correlation between IR ROM and KJOC score (r=0.467).The eccentric ER torque showed a fair negative correlates with the SDA (r=-0.489)and acromial distance (r=-0.470),as well as showed a fair positive correlate with the lower trapezius (LT) strength (r=0.444). Conclusion:We suggest a periodic evaluation and management is needed the variables that IR ROM, eccentric ER strength, and MT strength including depressed scapula.In addition, the IR ROM, forward and depressed scapular, and LT should be considered to improve the shoulder function and eccentric ER strength.