Objective: The purpose of this study was to determine if a preseason measurement of balance while in a unilateral stance could predict susceptibility to ankle injury in a cohort of high school basketball players. Predicting risk for ankle injury could be important in helping to reduce the risk of these injuries and furthermore save health care costs.
Design: Cohort study.
Setting: Data were collected at five high schools during the first 2 weeks of the 1997-1998 and 1998-1999 basketball seasons.
Subjects: 210 (119 male, age = 16.1 +/- 1.1 yr; height = 182.98 +/- 7.4 cm; weight = 76.4 +/- 10.9 kg; and 91 female, age = 16.3 +/- 1.3 yr; height = 170.9 +/- 7.8 cm; weight = 63.4 +/- 8.4 kg) high school basketball players who did not sustain a time loss ankle or knee injury within the previous 12 months served as subjects. Subjects did not use prophylactic ankle taping or bracing during the season.
Assessment of risk factors: Balance was quantified from postural sway scores measured while subjects performed unilateral balance tests with eyes both open and closed. Logistic regression analysis was carried out to determine if gender, dominant leg, and balance scores were related to ankle sprain injuries. In addition, Fischer's exact test was used to determine if the rate of ankle injuries was the same whether the subject had poor, average, or good balance. Balance was assessed by measuring postural sway with the NeuroCom New Balance Master version 6.0 (NeuroCom International, Clackamas, OR, U.S.A.). Testing to determine postural sway consisted of having subjects stand on one leg for three trials of 10 seconds with their eyes open, then repeated with their eyes closed. Subjects then underwent the same assessment while standing on the other leg. Postural sway was defined as the average degrees of sway per second (degrees S/S) for the 12 trials producing a compilation (COMP) score.
Outcome measures: Ankle injury resulting in missed participation.
Results: Subjects who sustained ankle sprains had a preseason COMP score of 2.01 +/- 0.32 (Mean +/- SD), while athletes who did not sustain ankle injuries had a score of 1.74 +/- 0.31. Higher postural sway scores corresponded to increased ankle sprain injury rates (p = 0.001). Subjects who demonstrated poor balance (high sway scores) had nearly seven times as many ankle sprains as subjects who had good balance (low sway scores) (p = 0.0002.)
Conclusion: In this cohort of high school basketball players, pre-season balance measurement (postural sway) served as a predictor of ankle sprain susceptibility.