The shoulder in swimming is subjected to multiple factors that can lead to a high injury rate. To prevent injury, one must understand the biomechanics of swimming. This paper describes the electromyographic and cinematographic findings of 12 shoulder muscles in competitive swimmers without shoulder pain. The results show the three heads of the deltoid and the supraspinatus functioning in synchrony to place the arm at hand entry and exit, the rhomboids and upper trapezius to position the scapula for the arm, the pectoralis major and latissimus dorsi to propel the body, the subscapularis and serratus anterior as muscles with constant muscle activity, the teres minor functioning with the pectoralis major, and the infraspinatus active only to externally rotate the arm at midrecovery. This information is important to design optimal preventative and rehabilitative exercise programs. (Pink M. Perry J. Browne A. Scovazzo ML. Kerrigan J. The normal shoulder during freestyle swimming. An electromyographic and cinematographic analysis of twelve muscles. American Journal of Sports Medicine. 19(6):569-76, 1991 Nov-Dec.)
The findings of this next study indicate that a relationship does exist between shoulder injury and the temporal recruitment patterns of the scapular rotators (trapezius and serratus anterior), such that injury reduces the consistency of muscle recruitment. They further suggest that injured subjects have muscle function deficits on their unaffected side also. (Wadsworth DJ. Bullock-Saxton JE. Recruitment patterns of the scapular rotator muscles in freestyle swimmers with subacromial impingement. International Journal of Sports Medicine. 18(8):618-24, 1997).
Swimmers with unilateral shoulder pain related to swimming compared to a control group with no present or previous history of shoulder pain showed that both groups of swimmers exhibited increased external range of motion and reduced internal range of motion compared with normalized data, but no between-group or side-to-side differences were detected. These findings suggest that prevention or rehabilitation of swimmer’s shoulder might not solely involve strengthening of the external rotators of the shoulder joint. Attention might also be drawn toward correction of a possible deficit in internal rotational strength. Changes in shoulder range of motion seem unrelated to the occurrence of shoulder pain. (Bak K. Magnusson SP. Shoulder strength and range of motion in symptomatic and pain-free elite swimmers. (American Journal of Sports Medicine. 25(4):454-9, 1997)
Breaststroke swimmers are at significant risk of groin injury, groin injury is positively correlated with increased magnitude of breaststroke training, and groin injury may prevent participation in practices and competitions.
The purpose of this following study was to examine the influence of a 3-wk period of electrostimulation training on the strength of the latissimus dorsi muscle and the swimming performances of 14 competitive swimmers divided into 7 electrostimulated (EG) and 7 control swimmers (CG). The peak torques registered during the flexion-extension of the arm was determined with the help of an isokinetic dynamometer at different velocities (from -60 degrees.s(-1) to 360 degrees.s(-1)). Performances were measured over a 25-m pull buoy and a 50-m freestyle swim. For Electrostimulated Group, a significant increase of the peak torques was measured in isometric, eccentric, and concentric conditions. The swimming times declined significantly by 0.19 +/- 0.14 s, for the 25-m pull-buoy, and by 0.38 +/- 0.24 s, for the 50-m freestyle. For the Control Group, no significant difference was found for any of the tests. These results showed that an electrostimulation program of the latissimus dorsi increased the strength and swimming performances of a group of competitive swimmers. (Pichon F. Chatard JC. Martin A. Cometti G. Electrical stimulation and swimming performance. Medicine & Science in Sports & Exercise. 27(12):1671-6, 1995)