Author(s): CHENG, I., CHUNG WEI, Y.J., HUANG, T.S., Institution: NATIONAL YANG MING CHIAO TUNG UNIVERSITY, Country: TAIWAN, Abstract-ID: 990

INTRODUCTION:
The history of previous shoulder pain has been investigated as an intrinsic risk factor for shoulder pain and may result in altered musculoskeletal characteristics in swimmers. In addition, the presence of generalized joint hypermobility may predispose the risk of muscle-tendon overload, increase muscle fatigue, and lead to shoulder pain. Hence, the main purpose of the current study was to explore the musculoskeletal characteristics in competitive swimmers with or without generalized joint hypermobility.
METHODS:
This cross-sectional study recruited 54 competitive swimmers, including 25 swimmers with generalized joint hypermobility. Shoulder internal rotation, external rotation, and horizontal adduction range of motion (ROM); cervical and thoracic posture and thoracic spine ROM; trunk rotational ROM; latissimus dorsi and pectoralis minor muscle length; glenohumeral joint laxity; shoulder and periscapular muscle strength and fatigue resistance; scapular dyskinesis; scapulothoracic and glenohumeral joint control ability, and upper quarter dynamic balance performance were collected. The data were analyzed using two-way analysis of variance (ANOVA) and binary linear regression to examine differences between swimmers with and without generalized joint hypermobility, and the relationship between generalized joint hypermobility and recurrent shoulder pain in swimmers.
RESULTS:
The results revealed significant group effects on shoulder external rotation ROM, horizontal adduction ROM, and scapular dyskinesis. Swimmers with generalized joint hypermobility exhibited excessive external rotation ROM, horizontal adduction ROM, and a lower incidence of scapular dyskinesis. Furthermore, there was a statistically significant interaction on serratus anterior muscle strength. Swimmers with recurrent shoulder pain and generalized joint hypermobility showed lower serratus anterior muscle strength than those without generalized joint hypermobility. No statistically significant differences were observed in the other parameters.
CONCLUSION:
Swimmers with generalized joint hypermobility may exhibit greater glenohumeral joint mobility. Additionally, swimmers without generalized joint hypermobility were more likely to exhibit scapular dyskinesis, enhancing the importance of scapular neuromuscular control. Finally, training the serratus anterior strength might be essential for swimmers with both generalized joint hypermobility and recurrent shoulder pain.