Paper Title
Weak Hamstrings Tightness, Weak Balance Ability and Asymmetric Trunk Rotation Caused Shoulder Pain in Male University Badminton Players

Abstract
Shoulder is one of the most common sites of badminton injury. Identifying risk factors of shoulder pain could better prevent shoulder injury. The purpose of this study was to identify intensity and risk factors of shoulder pain in college badminton players. Basic parameters (age, badminton experience, training hours per day, training times per week, etc.), physical fitness (hand grip strength, finger floor distance (FFD), heel buttock distance (HBD), straight leg raising (SLR), shoulder flexibility, balance, general joint laxity, shoulder and trunk joint range of motion, etc.) and intensity of shoulder pain were investigated using medical check-up among 15 male university badminton players (aged 18-21). The results showed that shoulder pain occurred in all players, and players with present shoulder pain had greater SLR degree (dominant side: 86.3° vs 72.2°, p < 0.05), weaker balance ability (nondominant side: 20.3s vs 57.5s, p < 0.05) and trunk right rotation deficit (right rotation minus left rotation: -2.8° vs 6.5°, p = 0.05). Visual analog scale (VAS) showed moderate shoulder pain in both groups of players with present and previous shoulder pain (51.8 mm and 40.6 mm, respectively). Greater SLR, weak balance ability and asymmetric trunk rotation are risk factors of shoulder pain. Identifying players with specific risk factors may enhance the prevention of badminton injury. Keywords - Badminton Injury, Shoulder Pain, Medical Check-Up, Racket Players