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 an d 10-week regular season. Setting: 10 public high schools in Texas. Participants: Two hundred fifteen varsity and junior varsity high school fo otball linemen. Main Outcome Measures: Injury rates (injuries per 1000 hours of playing tim e) for groups of players above a given body fat level and at or below a giv en 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 n ull hypothesis was that there is no difference in injury rates between play ers above a given level of body fat and those at or below that level of bod y fat. Body fat was determined from chest, abdomen, and thigh skinfold meas urements using standard conversion equations. Body mass index (BMl) (kg/m(2 )) was also calculated for each player. Results: The overall injury rate was 5.66 injuries per 1000 hours of playin g time. Percent body fat ranged from 9.3% to 40.2%. BMI ranged from 19.9 to 46.6 kg/m(2). Sixty-seven players sustained 86 injuries, the most common o f which were ankle sprains and medial collateral ligament sprains. No diffe rence 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 sign ificantly greater lower extremity injury rates than did players in lower fa t groups between 18% and 27% body fat and again 32% to 33%, but not at inte rmediate levels or >33%. Players in higher BMI groups had significantly gre ater lower extremity injury rates than did players in lower BMI groups thro ughout the range from 24 to 36 kg/m(2), except at 34 kg/m(2). Conclusion: Both higher body fatness and BMI were associated with increased rates of lower extremity injury among high school football linemen. BMI ap pears to be associated more consistently with increased lower extremity inj ury rates than is body fat.