Date of Award

1-1-2022

Degree Type

Thesis

Degree Name

Master of Science in Kinesiology

Department

Kinesiology

First Advisor

Susan E. D’Andrea

Abstract

Background Swimmers, in general are understudied compared to other athletes, therefore, there is especially little investigation regarding the specific causes of shoulder pain in swimmers available (Tovin, 2006a). From existing literature, there are established normal and non-shoulder pain producing muscular activations and upper body kinematics during the freestyle stroke (Pink et al., 1991), however, it is difficult for investigators to make conclusions about the associations between improper freestyle stroke techniques, improper muscular functioning and shoulder pain (Pink & Tibone, 2000). Therefore, the purpose of this study is to assess differences in the coactivation of triceps brachii and biceps brachii, and elbow angle in swimmers with and without shoulder pain.

Methods 20 elite level swimmers participated in this study, 10 with shoulder pain and 10 without. Participants filled out the Penn Shoulder Score (PSS) and Disabilities of the Arm, Shoulder, and Hand (DASH) Outcome Measure to quantify shoulder pain. Swimmers participated in five, 2-minute trials of simulated freestyle swimming on a customized swim ergometer. Biceps and triceps activity were measured using electromyography, and elbow kinematics were assessed using motion capture. Significance was set at p  0.05.

Results The stroke was divided into Early and Late phase, based on the position of the upper arm to the shoulder. During the entire freestyle stroke, the Pain group demonstrated significantly greater right biceps co-contraction index (CCI) (p<.0003). During the Early phase of the stroke, the Pain group had significantly greater peak elbow angles on both sides (p<.0058). The Pain group also had a greater right peak biceps activation (p<.0001) and a greater right peak triceps activation (p=.0046) during the Early phase of the stroke. In the Late phase of the stroke, the No Pain group had a greater right elbow angle (p=.0230), while the Pain group had a greater right peak biceps activity (p=.0002). In the Late phase of the stroke, there was a moderate association between left peak biceps activation and left peak elbow angle (R2 = 0.598, p<.0001).

Conclusions Swimmers with shoulder pain had different biceps and triceps activation patterns and elbow kinematics than swimmers without shoulder pain. Those with shoulder pain are seen to have decreased elbow flexion in the late phase of the stroke and greater biceps activation in lieu of lesser triceps activation. Additional research is needed examining the biceps and triceps muscle activity during freestyle swimming. Examining biceps and triceps coactivation, elbow mechanics and associations between stroke mechanics and injuries may allow for preventative protocols to be developed.

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