Paper Title
COMPARING PHYSICAL FITNESS BETWEEN YOUTH TENNIS PLAYERS WITHS A HISTORY OF SHOULDER INJURIES AND THOSE WITHOUT

Abstract
BACKGROUND/AIMS: Shoulder injuries which affects sports performance and activities of daily life, is the high frequency injury site experienced by tennis players. However, studies on physical fitness among youth tennis players are scarce. This study aimed to check the differences in physical fitness characteristics between youth tennis players with shoulder injury and those without. METHODS: Physical fitness evaluation tests were performed among twenty-six youth elite tennis players aged 15-19 years using medical check-ups. The tests included general joint laxity, straight leg raising, single leg stance, Y-balance test, shoulder range of motion (ROM), and trunk range of motion. According to a history of shoulder injuries, the players were divided into non-injured group (n = 20) and injured group (n = 6), and the differences in physical fitness characteristics between the two groups were compared. Independent-samples t-testand Mann-Whitney U test were used for data analysis. RESULTS: Significant differences in shoulder internal rotation (IR) angle (non-injured group vs injured group: 99.28° ± 12.87° vs 83.21° ± 9.45°, p = 0.009) and total range of motion (TROM) angle (non-injured group vs injured group: 212.62° ± 15.61° vs 193.15° ± 21.87°, p = 0.02) of non-dominant side existed between the two groups. Moreover, glenohumeral internal rotation deficit (GIRD) angle (non-injured group vs injured group: 9.21° ± 11.68° vs -2.52° ± 12.83°, p = 0.04) had significant difference between the two groups.In terms of Y-balance test, there were significant difference in the posterolateral reach distance of the right leg between the non-injured group and the injured group (non-injured group vs injured group: 96.35 cm ± 7.96 cm vs 89.83 cm ± 6.08 cm, p = 0.03). CONCLUSIONS: Youth elite tennis players with a history of shoulder injuries presented significantly weaker IR angle, TROM angle, and GIRD angle compared with those without. These findings might assist coaches and youth tennis players in maintaining targeted physical fitness plan aimed at reducing tennis-related injuries.