Body fatness and increased injury rates in high school football linemen.

OBJECTIVE

To determine whether associations exist between body fatness and injury rates in high school football linemen.

DESIGN

Prospective, injury surveillance study during a 2-week preseason and 10-week regular season.

SETTING

10 public high schools in Texas.

PARTICIPANTS

Two hundred fifteen varsity and junior varsity high school football linemen.

MAIN OUTCOME MEASURES

Injury rates (injuries per 1000 hours of playing time) for groups of players above a given body fat level and at or below a given body fat level. Rates were computed as the number of injuries per group divided by the group's aggregate playing time (practice + game time). The null hypothesis was that there is no difference in injury rates between players above a given level of body fat and those at or below that level of body fat. Body fat was determined from chest, abdomen, and thigh skinfold measurements using standard conversion equations. Body mass index (BMI) (kg/m2) was also calculated for each player.

RESULTS

The overall injury rate was 5.66 injuries per 1000 hours of playing time. Percent body fat ranged from 9.3% to 40.2%. BMI ranged from 19.9 to 46.6 kg/m2. Sixty-seven players sustained 86 injuries, the most common of which were ankle sprains and medial collateral ligament sprains. No difference in overall injury rates between higher and lower fat groups was seen at any body fat level. Players in higher body fat groups, however, had significantly greater lower extremity injury rates than did players in lower fat groups between 18% and 27% body fat and again 32% to 33%, but not at intermediate levels or >33%. Players in higher BMI groups had significantly greater lower extremity injury rates than did players in lower BMI groups throughout the range from 24 to 36 kg/m2, except at 34 kg/m2.

CONCLUSION

Both higher body fatness and BMI were associated with increased rates of lower extremity injury among high school football linemen. BMI appears to be associated more consistently with increased lower extremity injury rates than is body fat.