Author(s): KAWABATA, M., TANAKA, Y., SAITO, Y., SANO, Y., UCHIDA, Y., WATANABE, H., TAKAHIRA, N., Institution: KITASATO UNIVERSITY GRADUATE SCHOOL OF MEDICAL SCIENCE , Country: JAPAN, Abstract-ID: 2777

INTRODUCTION:
Background: Dynamic shoulder stability is essential for injury prevention and performance maintenance in overhead sports. The dynamic shoulder supporter (DSS) was developed to enhance glenohumeral dynamic stabilization; however, its immediate perceptual effects during short-duration exercise have not been investigated.

Purpose: To examine the immediate effects of short-duration exercise performed while wearing the DSS on perceived ease of arm swing during shadow swinging in collegiate male volleyball players.

METHODS:
Methods: Eighteen collegiate male volleyball players participated. Based on the previously reported symptomatic cutoff value of 87.6 points on the Japanese Version of the Kerlan-Jobe Orthopaedic Clinic (J-KJOC) score1）, participants were classified into a symptomatic group (n = 8, < 87.6 points) and a well-functioning group (n = 10, >= 87.6 points). After a 1-week familiarization period with shoulder exercises, immediate changes were assessed by comparing shadow swinging performed just before the intervention with that performed immediately after 2 minutes of shoulder exercises (external rotation, internal rotation, elevation, abduction, horizontal abduction, and arm circles) while wearing the DSS. Perceived ease of arm swing was rated using a 21-point scale ranging from -10 (much worse) to 0 (no change) to +10 (much better). Scores were categorized as deterioration (-10 to -4), no change (-3 to 3), or improvement (4 to 10). Improvement rates were compared using Fisher's exact test, and changes in scores between groups were analyzed using the Wilcoxon rank-sum test.
RESULTS:
Results: The median change score [interquartile range] was 6 [5.8 to 8.3] points in the symptomatic group and 2 [0.5 to 6.8] points in the well-functioning group. Although the between-group difference did not reach statistical significance (p = 0.097), the symptomatic group demonstrated a numerically greater improvement.
CONCLUSION:
Conclusion: While the between-group difference in change scores did not reach statistical significance, the magnitude and direction of the observed changes suggest a potentially greater immediate benefit in symptomatic players. These findings should be interpreted cautiously due to the small sample size and limited statistical power.