Alterations in body composition of obese females following in-community supervised exercise program

ABSTRACT

BACKGROUND: A variety of techniques for assessing human composition have been developed. However, the validity of these methods has not been compared in the same subjects after training program. In this study, the dependent variable used as a criterion of changes in body composition is body weight (BW), which consists of fat-free weight (FFW) and body fat (BF) in the two compartment model, on the assumption that FFM does not change significantly during the exercise program. The purpose of this investigation was to evaluate the validity of percentage body fat using indirect methods - bioelectrical impedance (Bl) analyzer and skinfold thickness (SFT) and to discuss the accuracy of each method. METHODS: The subjects were 13 obese women, aged 42 to 63 fears (52.4+/-6.4yr) . The subjects participated in supervised physical conditioning program 3 days per week, 30 to 60 min each session, for a period of 14 weeks. RESULTS: Small decrements were observed in BW (0.5+/-1.9 kg, p>0.05) , body mass index (BMI, 0.6+/-1.8, p>0.05), waist girth (2.1 cm, P<.06), and SFT at the triceps (2.9mm, P<0.05) and subscapular (2.9mm, P<0.05) . There were significant changes in BF (P<0.001) and FFM (P<0.001) calculated by the SFT method, while mean FFM computed by Bl technique remained essentially unchanged. Correlational analysis indicated that the absolute amount of change in BW (i.e., delta BW) was significantly associated with delta abdominal girth and delta BF estimated by the BI technique. The relationship between delta BW and delta BF estimated by the SFT method technique was not statistically significant, thereby questioning the validity of using individual skinfold measurements solely to estimate alterations in body composition. CONCLUSIONS: From these results, it is concluded that Bl technique may provide more accurate estimates of changes in BF than SFT method.