Body composition and physical activity in Italian university students

Background: Increased sedentary lifestyle and prevalence of overweight/obesity are common in western countries. The purposes of this study were (i) to assess the main health-related anthropometric characteristics in a sample of students in relation to sex, amount of physical activity and sport discipline, and (ii) to investigate the accuracy of the Body Mass Index (BMI) and Waist-to-Stature Ratio (WSR) as indicators of body fat percentage (%F) in young adults. Methods: 734 university students, both sexes, participated in the present research. A self-administered questionnaire acquired socio-demographic information (sex, age) and sport participation (hours/week, sport discipline). Anthropometric measurements and grip strength values were acquired according to standardized procedures. Body composition was assessed by means of the skinfold method. Results: Most students had normal BMI, WSR and %F. There were significant statistical differences in all anthropometric traits between the two sexes. One-way ANOVAs within sex showed statistically significant differences in biceps skinfold, waist circumference (WC), WSR, body density (BD), %F and fat mass (FM) among different levels of physical activity in males; and in weight, BMI, arm girths and fat free mass (FFM) in females. One-way ANOVAs within sex showed statistically significant differences in arm girths, grip strength and FFM among different sport disciplines in males, and in height, weight, BMI, WC, relaxed arm girth, grip strength, FM and FFM in females. Despite the significant and positive correlation of BMI and WSR with %F both indices had poor sensitivity. Conclusions: Physical activity plays an important role in body composition parameters: the most active males had the least amount of FM and the most active females had the greatest amount of FFM. BMI and WSR are not accurate indices of adiposity in young adults.