Hip Strength as a Predictor of Ankle Sprains in Male Soccer Players: A Prospective Study.

CONTEXT:   Diminished hip-abductor strength has been suggested to increase the risk of noncontact lateral ankle sprains.

OBJECTIVE:   To determine prospectively whether baseline hip-abductor strength predicts future noncontact lateral ankle sprains in competitive male soccer players.

DESIGN:   Prospective cohort study.

SETTING:   Athletic training facilities and various athletic fields.

PATIENTS OR OTHER PARTICIPANTS:   Two hundred ten competitive male soccer players.

MAIN OUTCOME MEASURE(S):   Before the start of the sport season, isometric hip-abductor strength was measured bilaterally using a handheld dynamometer. Any previous history of ankle sprain, body mass index, age, height, and weight were documented. During the sport season (30 weeks), ankle injury status was recorded by team medical providers. Injured athletes were further classified based on the mechanism of injury. Only data from injured athletes who sustained noncontact lateral ankle sprains were used for analysis. Postseason, logistic regression was used to determine whether baseline hip strength predicted future noncontact lateral ankle sprains. A receiver operating characteristic curve was constructed for hip strength to determine the cutoff value for distinguishing between high-risk and low-risk outcomes.

RESULTS:   A total of 25 noncontact lateral ankle sprains were confirmed, for an overall annual incidence of 11.9%. Baseline hip-abductor strength was lower in injured players than in uninjured players ( P = .008). Logistic regression indicated that impaired hip-abductor strength increased the future injury risk (odds ratio = 1.10 [95% confidence interval = 1.02, 1.18], P = .010). The strength cutoff to define high risk was ≤33.8% body weight, as determined by receiver operating characteristic curve analysis. For athletes classified as high risk, the probability of injury increased from 11.9% to 26.7%.

CONCLUSIONS:   Reduced isometric hip-abductor strength predisposed competitive male soccer players to noncontact lateral ankle sprains.