Body Mass Index (BMI), mass (kg)/height (m2), is used to determine overweight and obesity. However, BMI does not directly measure body composition, so BMI may misclassify individuals. The relationship between BMI and body composition has previously been studied in football and soccer players, but there is little research that has been done on non-contact sport athletes.
PURPOSE: To determine the relationship between BMI and body composition as measured by air-displacement plethysmyography (ADP) in collegiate athletes from non-contact sports.
METHODS: One hundred and eighteen collegiate athletes participated in the study. Participants included male (n=55) and female (n=63) non-contact sport athletes. Body composition measures included height, weight and whole body adiposity via ADP. The Kappa statistic was used to demonstrate agreement.
RESULTS: Descriptive data (means and standard deviations) were calculated for each group (Males - Height: 181.9 cm ± 6.6, Mass: 81.7 kg ± 11.9, BMI: 24.6 kg/m2 ± 2.9, BF: 11.0% ± 5.5; Females - Height: 165.8 cm ± 6.5, Mass: 63.4 kg ± 7.8, BMI: 23.0 kg/m2 ± 2.3, BF: 20.9% ± 5.5). According to BMI status, 0.8% were underweight, 66.1% were normal weight, 31.4% were overweight and 1.7% were obese. According to body fat percentage 3.4% were underweight, 91.5% were normal, 3.4% were overweight and 1.7% were obese. Categorical classification accuracy between BMI and body fat percentage was 66.1%. Kappa was statistically significant (p=0.013) with a value of 0.117, indicating slight agreement.
CONCLUSION: BMI measures and body fat percentage agree 2/3 of the time. The majority of the misclassification errors occur when BMI classifies non-contact sport athletes as overweight, while body fat percentage classifies them as having normal body fat.