Effects of hormone replacement therapy and high-impact physical exercise on skeletal muscle in post-menopausal women: a randomized placebo-controlledstudy

An age-related decline in muscle performance is a known risk factor for fai ling, fracture and disability. In women, a clear deterioration is observed from early menopause. The effect of hormone replacement therapy (HRT) in pr eserving muscle performance is, however, unclear. This trial examined the e ffects of a 12-month HRT and high-impact physical exercise regimen on skele tal muscle in women in early menopause. A total of 80 women aged 50-57 year s were assigned randomly to one of four groups: exercise (Ex), HRT, exercis e+HRT (ExHRT) and control (Co). The exercise groups participated in a high- impact training programme. The administration of HRT (oestradiol/noretister one acetate) or placebo was carried out double-blind. Knee extension torque and vertical jumping height were evaluated. Lean tissue cross-sectional ar ea (LCSA) and the relative proportion of fat within the muscle compartment were measured for the quadriceps and lower leg muscles. The ExHRT group sho wed significant increases in knee extension torque (8.3%) and vertical jump ing height (17.2%) when compared with the Co group (-7.2%). Vertical jumpin g height also increased after HRT alone (6.8%). The LCSA of the quadriceps was increased significantly in the HRT (6.3%) and ExHRT (7.1%) groups when compared with the Ex (2.2%) and Co (0.7%) groups. Lower leg LCSA was also i ncreased in the ExHRT group (9.1%) when compared with the Ex (3.0%) and Co (4.1%) groups. In addition, the increase in the relative proportion of fat in the quadriceps in the Co group (16.6%) was significant compared with tho se in the HRT (4.9%) and ExHRT (-0.6%) groups. Thus, in post-menopausal wom en, muscle performance, muscle mass and muscle composition are improved by HRT. The beneficial effects of HRT combined with high-impact physical train ing may exceed those of HRT alone.