The Normal and the Painful Shoulders During the Breaststroke

Abstract

The purpose of this study was to describe and compare electrical activity patterns in 12 shoulder muscles during the breaststroke in 25 competitive swimmers who had normal shoulders and in 14 who had painful shoulders while they performed this stroke in a pool. The electro myographic analysis was synchronized with high-speed cinematography to discern phases of the breaststroke. Means, standard deviations, and t-tests were done for each phase. The differences in muscle activity between the two groups of swimmers demonstrated an increase in the internal rotators in the group with painful shoul ders. They also demonstrated a decrease in the teres minor, supraspinatus, and the upper trapezius muscles. These factors increase the risk of impingement. Both the serratus anterior and teres minor muscles in the swimmers with normal shoulders consistently fired at or above 15% manual muscle test throughout the breast stroke cycle and were thus subject to fatigue. Based on these results, exercises for the breaststroke swimmer should be directed toward endurance training of the ser ratus anterior and teres minor muscles while balancing the internal and external rotators of the shoulder as well as the deltoid and supraspinatus muscles.