Examining Changes in Shoulder Strength, Lower Body Power, and Body Composition among Collegiate Baseball Players after Completion of a Summer Baseball League Season

• Published in: Journal of functional morphology and kinesiology Vol. 9; no. 2; p. 98
• Main Authors: Merfeld, Brandon, Rowley, Matthew, Almonroeder, Thomas, Luedke, Joel, Erickson, Jacob L, Jones, Margaret T, Fields, Jennifer B, Szymanski, Elijah, Jagim, Andrew R
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31.05.2024; MDPI
• Subjects: arm strength; athlete monitoring; Athletes; Baseball; Baseball players; Biomechanics; Body composition; Data collection; Force; Injuries; overhead athletes; Physiological aspects; Risk factors; Sports associations; Sports injuries; Summer; throwing arm; Training; Velocity; United States > US; arm strength; throwing arm; athlete monitoring; overhead athletes
• ISSN: 2411-5142; 2411-5142
• DOI: 10.3390/jfmk9020098

The strength of the shoulder musculature involved with internal rotation and arm extension plays an important role in the overhead throwing motion for baseball athletes, both for throwing-related performance and injury risk. The maintenance of shoulder strength is a high priority for baseball athletes throughout a season; however, little is known in regards to the expected changes in strength throughout a season. To examine pre-post changes in shoulder strength, lower body power, and body composition among collegiate baseball players after the completion of a summer baseball league season. Amateur baseball players ( = 12; age: 20.9 ± 1.0 years.; height: 181.6 ± 5.6 cm; body mass: 86.4 ± 11.1 kg; BMI: 26.0 ± 2.6 kg/m ) participated in the current study. Pre- and post-competitive season, the participants completed shoulder strength assessments and body composition and countermovement vertical jump (CMJ) tests. An upper-body isometric test (athletic shoulder [ASH] test) was used to evaluate shoulder strength for each arm. Each subject completed maximal isometric contractions for both the throwing and non-throwing arms at four separate angles of abduction (180°, 'I'; 135°, 'Y'; 90°, 'T'; and -180°, 'A') while lying in a prone position. For shoulder strength, the primary dependent variable of interest was a composite measure that represented the average of the forces produced across all four positions of the ASH test (I, Y, T, A). For the ASH test composite measure, there was a trend toward a significant arm-by-time interaction effect ( = 0.08), as shoulder strength decreased by 9.03% for the throwing arm (ES = 0.72; 95% CI = [-0.27, -0.01]), compared to only 2.03% for the non-throwing arm (ES = 0.15; 95% CI = [-0.16, 0.09]), over the course of the season. The main effects of time ( = 0.16) and arm ( = 0.58) were not significant for the ASH test composite measure. There was no relationship between lower body power and throwing arm strength at baseline (r = 0.20, = 0.56), and only a non-significant weak relationship at post-test (r = 0.28, = 0.41). Throughout a season, baseball players may experience reductions in shoulder strength of the throwing arm with minimal changes in shoulder strength in the non-throwing arm.