The Impact of EightWeeks Closed and Open Kinetic Chain Exercise on Ratio of the External to Internal Shoulder Rotator Muscles’ Strength in Top Swimmers

Objectives: Based on previous studies, the strength ratio of internal to external rotator muscles of the shoulder in elite swimmersis a predisposing factor of impingement syndrome. So this study was done to compare the effect of open and closed kinetic chainexercises on this ratio.Methods: Regarding the inclusion criteria, ۴۵ swimmers were selected and distributed randomly to ۳ groups of the open chain(۱۵), closed chain (۱۵), and control (۱۵). Exercise prescribed for both open and closed chain groups three times per week, but thecontrol group was deprived. Before starting the exercise and after eight weeks, the strength ratio of the internal to the externalrotator shoulder muscles in both eccentric and concentric contraction was measured at various speeds of ۶۰, ۱۲۰, and ۱۸۰ degrees/s.Subsequently, one-way ANOVA and Tukey post hoc tests were performed to compare the groups and show the intra-group difference(P < ۰.۰۵).Results: Both types of exercises reduced the strength ratio of internal to external shoulder rotator muscles in both contractions.There was no significant difference between closed and open chain exercises, but the open chain reduced the ratio of internal toexternal rotator muscles’ strength less than the closed chain in both types of contractions.Conclusions: To reduce the ratio of internal to external rotator muscles’ strength in swimmers and improve the muscle imbalance,open kinetic chain exercises are more effective than closed kinetic chain exercises and can be recommended for prevention andrehabilitation of swimmer’s shoulder.

کلیدواژه ها:

Shoulder Internal Rotator Muscles ، Shoulder External Rotator Muscles ، Open Kinetic Chain ، Closed Kinetic Chain ، Shoulder Impingement Syndrome ، Swimmer’s Shoulder