To investigate the effects of combined resistance and aerobic training with protein intake on body composition in obese middle-age women.

42 obese middle-aged women (average age: 56.5±4.3; BMI: 26.6±2.3kg/m2; body fat: 35.9±2.2%) were given either a protein and glucose supplement (10g protein, 15g glucose, 0g fat), glucose placebo (0g protein, 25g glucose, 0g fat), or calorie-free placebo (0g protein, 0g glucose, 0g fat), and a parallel-group comparison study performed. Subjects engaged in a continuous 10-week training program that combined muscle training five days a week with aerobic training. Subjects consumed the above supplements and placebos immediately after each exercise regimen. A cross-sectional MRI of psoas major muscle mass was taken before and after the 10-week training regimen.

While there was some difference in growth in psoas major muscle mass through training between the groups consuming a calorie-free placebo and a standard placebo, the group consuming a protein and glucose supplement showed significantly more growth over the former two groups.

The above results suggest that protein intake immediately after an exercise program consisting of muscular and aerobic training is effective in increasing the cross-sectional muscle area of the psoas major muscle, which is used in walking and climbing stairs - actions which involve bending the hips and represent the highest proportion of bodily movements in an everyday context.