Risk Factors for Noncontact Ankle Injuries in Amateur Male Soccer Players: A Prospective Cohort Study.

OBJECTIVE: To determine whether nonmodifiable and modifiable risk factors [ankle dorsiflexion range of motion (ROM), lower limb power output, and balance], as identified in preseason screening, predict the risk of sustaining a noncontact ankle injury in amateur male soccer players during the training and competitive season.

DESIGN: Prospective cohort study.

SETTING: Amateur soccer competition (club and area representative teams).

PARTICIPANTS: Amateur soccer players (n = 210) aged ≥15 years.

ASSESSMENT OF RISK FACTORS (INDEPENDENT VARIABLES): Height, weight, ankle dorsiflexion ROM, power (vertical jump) and balance (time of double-leg balanced stance on an electronic wobble board, maximum 20 seconds) measured in preseason screening.

MAIN OUTCOME MEASURES (DEPENDENT VARIABLE): Incidence of noncontact ankle injury and exposure to both training and games, monitored during the competitive season following baseline measurement. Noncontact ankle injury was defined as any ankle injury not caused by a collision (with another player or object) resulting in a participant missing at least 1 game or training session.

RESULTS: Fourteen of the 210 participants (6.7%) sustained a noncontact ankle injury yielding an injury rate of 0.484 injuries per 1000 player hours. Lower limb power output scores <30 W/kg [odds ratio (OR), 9.20, 95% confidence interval (CI), 1.13-75.09, P = 0.038] and poorer balance scores (OR, 0.43, 95% CI, 0.21-0.89, P = 0.024) were associated with higher odds of injury.

CONCLUSIONS: Poorer lower limb power output and balance are risk factors for noncontact ankle injury among amateur soccer players. These deficits can potentially be identified by screening, providing opportunities to investigate prevention strategies.