STRENGTH CHANGES INDUCED BY EXTREME DIETING AND EXERCISE IN SEVERELY OBESE FEMALES

Strength changes, induced by very low-calorie diet (VLCD, 520 kcal/day ) alone and in combination with exercise, were determined in 109 sever ely obese females (46.8 +/- 4.69% fat). Experimental treatments includ ed VLCD alone (LC, n = 40), VLCD with endurance exercise (EE, n = 23), VLCD with endurance exercise and resistance strength training (EERST, n = 23), and VLCD with resistance strength training (RST, n = 23). Al l subjects participated in the study for 90 days while EE, EERST, and RST exercised four times/week according to specified schedules. Result s indicated significant differences for the change scores (baseline to 90 days) for bench press, knee flexion, upper body and lower body com posite strength scores between RST and all other groups. RST was the o nly treatment that increased upper and lower body strength. No differe nces between groups were found for body mass losses, decreases in perc ent fat and fat mass. In contrast, these variables showed significant change scores for all groups. Decreases in fat-free mass (FFM) were 5. 18 +/- 3.40 kg, 4.79 +/-4.15 kg (p = 0.001), 4.64 +/- 4.23 kg, and 3.2 6 +/- 2.67 kg for EE, LC, RST, and EERST, respectively. These data sug gest that the combination of resistance strength training and VLCD inc reases strength despite a loss of FFM. However, endurance exercise and VLCD do not seem to affect body mass loss or FFM loss per se. Moreove r, it seems that these increases in strength may represent a training effect which might imply improved central neuromuscular function rathe r than muscular hypertrophy since FFM decreased in all groups.