Risk factors for noncontact ankle sprains in high school football players: the role of previous ankle sprains and body mass index.

BACKGROUND

In a previous study, we noted a possible connection between an athlete's weight and risk of ankle sprain.

HYPOTHESIS: A high body mass index and a history of a previous ankle sprain increase the risk of a subsequent noncontact sprain.

STUDY

DESIGN

Cohort study; Level of evidence, 2.

METHODS

One hundred fifty-two athletes from 4 football teams were observed (2 varsity and 2 junior varsity). Two teams were observed for 3 seasons, and 2 teams were observed for 1 season. Before each season, body mass, height, history of previous ankle sprains, and ankle tape or brace use were recorded.

RESULTS

There were 24 ankle sprains, of which 15 were noncontact inversion sprains (11 grade I, 3 grade II, 1 grade III; incidence, 1.08 per 1000 athlete-exposures). Injury incidence was higher in athletes with previous ankle injuries (2.60 vs 0.39; P < .001). Body mass index was also a risk factor (P < .05): injury incidence was 0.52 for players with a normal body mass index, 1.05 for players at risk of overweight, and 2.03 for overweight players. Injury incidence was 0.22 for normal-weight players with no previous ankle sprain compared with 4.27 for overweight players who had a previous sprain.

CONCLUSION

An overweight player who had a previous ankle sprain was 19 times more likely to sustain a noncontact ankle sprain than was a normal-weight player with no previous ankle sprain.

CLINICAL RELEVANCE: Ankle sprain prevention strategies should be targeted at football players with a high body mass index and a history of previous ankle sprains.