Change in Body Weight and Body Composition on Muscular Strength and Function in Overweight Adults

Abstract

PURPOSE: To examine the relationship between the changes in body weight and lean body mass with changes in muscular strength and function in overweight and obese adults before and after a 12 week weight loss intervention. METHODS: Fifty-seven overweight adults (age = 41.3 ± .87 years; BMI = 33.1 ± 2.8 kg/m2; % body fat = 42.4+ 3.8 %) participated in this study. Forty eight subjects completed the 12 week weight loss intervention consisting of behavioral counseling. Subjects were instructed to reduce energy intake to 1200 to 1500 kcal/d and to increase exercise to 30 to 40 min/d on 5 d/wk. Participants completed assessments of body weight, body composition using the BIA method, muscular strength (1 -RM chest press, 1-RM leg extension, grip strength), and physical function (sit-to-stand) at baseline and following the 12-week intervention. RESULTS: Paired sample T-tests revealed a significant decrease in body weight, lean body mass, 1 -RM chest press, and 1 -RM leg extension (p<0.05), with no significant change in grip strength from baseline to 12-weeks (see Table 1). However there was a significant increase in physical function (sit-to-stand score) from baseline to 12-weeks (p<0.05) (Table 1), with the significant relation observed for percent change in body weight and the change in physical function (r = 0.35; p<0.05).Table 1CONCLUSION: The observed reduction in body weight was associated with a concurrent reduction in LBM and muscular strength. However, these reductions did not negatively impact physical function, but rather were accompanied by an increase in physical function. This increase in physical function may impact quality of life, and demonstrates the additional benefits of promoting weight loss in overweight and obese adults.