Preseason Aerobic Fitness Predicts In-Season Injury and Illness in Female Youth Athletes

BACKGROUND: Although preseason aerobic fitness has been suggested as a modifiable risk factor for injury in adult athletes, the relationship between aerobic fitness, injury, and illness in youth athletes is unknown. PURPOSE: To determine whether preseason aerobic fitness predicts in-season injury and illness risk in female adolescent soccer players. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Fifty-four female adolescent soccer players underwent preseason evaluation to determine years of experience, body mass index (BMI), maximal aerobic capacity (VO(2max)), and time to exhaustion (T(max)) during cycle ergometer testing. All injuries and illnesses during the subsequent 20-week season were recorded. Variables were compared between individuals with and without a self-reported injury and individuals with and without a self-reported illness. Separate Poisson regression models were developed to predict number of injuries and illnesses for each individual by use of age, years of experience, BMI, VO(2max), and T(max.) RESULTS: Twenty-eight injuries and 38 illnesses in 23 individuals were recorded during the season. Although not a statistically significant finding, individuals who reported an in-season injury had lower VO(2max) than those who did not (54.9 ± 7.3 vs 58.3 ± 8.5 mL/kg/min, P = .13). Individuals who reported an illness had significantly lower VO(2max) than those who did not (54.5 ± 9.9 vs 58.8 ± 6.2 mL/kg/min, P = .014). With the Poisson regression models, VO(2max) was a significant predictor of both injury (odds ratio [OR], 0.95; P = .046) and illness (OR, 0.94; P = .009), while no significant relationships were identified between injury or illness and age, years of experience, T(max), or BMI (all P > .05). CONCLUSION: Among adolescent female soccer players, greater preseason aerobic fitness is associated with a reduced risk of in-season injury and illness. Off-season intervention to promote aerobic fitness may help reduce the risk of lost time during the season due to injury and illness.