Comparison of Isolation Ratios of the Scapular Retraction Muscles between Protracted Scapular and Asymptomatic Groups

[Purpose] The purpose of this study was to compare the isolation ratios of scapular retraction muscles between protracted scapular and asymptomatic groups. [Subjects] Seven males with protracted scapular and seven asymptomatic males aged 20–30 years were recruited. [Methods] We measeured the rhomboid, middle trapezius (MT), and lower trapezius (LT) muscles activities, and calculated the isolation ratio. [Results] The rhomboid and MT isolation ratio of the protracted scapular group was not significantly different from that of the asymptomatic group. The LT isolation ratio of the protracted scapular group was significantly lower than that of the asymptomatic group. [Conclusion] We suggest that a proper retraction exercise, for patients with protracted scapular posture is one that includes exercises for selectively strengthening the lower trapezius muscle.