Paper Title
Risk Factors of Ankle Injury in University Badminton Players

Abstract
Badminton is a popular racket sport played by more than 330 million people worldwide. Ankle injury is the most common injury in badminton players. Nevertheless, studies on badminton-related ankle injury using medical check-up are scarce. Purpose: This Study Aimed to Identify Risk factors of Ankle Injury in University Badminton Players Methods: 51 university badminton players (25 males and 26 females) who participated in the national tournament of Japan, completed a self-reported questionnaire on basic parameters and a history of ankle injury. Physical fitness tests of medical check-up comprising of straight leg raising (SLR) angle, heel buttock distance (HBD), single leg stance and full deep squat, were performed. Chi-square test was utilized to analyze the data. Odds ratio (OR) and 95% confidence interval (CI) were calculated. Results: 51 badminton players (mean age:19.8 years; mean height: 165.3 cm; mean weight: 60.1 kg; mean badminton experience: 11.6 years) without current ankle injury were studied. In them, 14 badminton players (3 males, 11 females) experienced a history of ankle injury. Compared with the male players, the female players showed significantly higher presence of ankle injury (OR = 5.38, 95%CI: 1.28-22.59, p = 0.015; Fisher’s Exact test: p = 0.027). Among all the badminton players, the badminton players without full deep squat showed 3.63 times more likely to sustain ankle injury (OR = 3.63, 95% CI: 0.98-13.41, p = 0.047) than those with full deep squat. Of the female players, the female players without full deep squat showed 11.67 times more likely to sustain ankle injury than those with full deep squat (OR = 11.67, 95% CI: 1.11-122.38, p = 0.02). Conclusion: Tight ankle joint might be a risk factor for ankle injury in university badminton players, especially for female badminton players. Coaches, players, and physiotherapists should focus on the ankle laxity to prevent ankle injury.