HORMONE REPLACEMENT THERAPY DOES NOT AUGMENT GAINS IN MUSCLE STRENGTHOR FAT-FREE MASS IN RESPONSE TO WEIGHT-BEARING EXERCISE

Lower extremity strength and fat-free mass were examined in 58 postmen opausal women aged 60-72 yr. Subjects were studied before and after an 11-mo control period (n = 16) or before and after an 11-mo weight-bea ring exercise training program designed to generate relatively high gr ound reaction forces (n = 42). Twenty-two of the exercisers initiated hormone replacement therapy (HRT) at the outset of exercise and contin ued HRT for 11 mo. Hip extension and abduction strength were assessed using a hand-held dynamometer. Force production during knee extension and flexion was evaluated on an isokinetic dynamometer at 60, 90, and 180 degrees/s. Simultaneous knee and hip extension strength was also a ssessed on a leg press machine. Total body and lower extremity fat-fre e mass were determined using dual-energy x-rap absorptiometry. There w ere no significant changes in muscle strength or body composition in c ontrol subjects. Both exercise groups had significant increases in fat free mass and in all strength measures. Fat free mass increased from 38.8 +/- 4.3 to 39.7 +/- 4.3 kg in the exercise group and from 37.7 +/ - 3.9 to 38.9 +/- 4.6 kg in the exercise-plus-HRT group. The average r elative increase in strength was 16.2 +/- 11.0% in the exercise group and 17.0 +/- 13.0% in the exercise-plus-HRT group. Women receiving HRT did not have a gain in fat-free mass or in strength over and above th at demonstrated by the women not on HRT. Our results provide evidence that HRT does not augment the increases in muscle mass or strength tha t occur in response to weight-bearing exercise in older women.