Changes in muscle strength in women following the menopause: a longitudinal assessment of the efficacy of hormone replacement therapy

The effects of hormone deficiency at the menopause on muscle strength was e xamined in 10 healthy middle-aged women (1-3 years post-menopause) in a lon gitudinal trial over 39 weeks. Performance was compared with that of age-ma tched females (n = 11) taking a course of hormone replacement therapy (HRT) . Muscle strength of the quadriceps was measured isometrically at 90 degree s of knee flexion and at angular velocities of 1.05, 2.09 and 3.13 rad/s us ing an isokinetic dynamometer. Hand grip strength was assessed by means of a portable dynamometer. Measurements were taken every 13 weeks for 39 weeks . Significant decreases in isometric strength (-10%) and dynamic leg streng th at 1.05 rad/s (-9%) were found in the postmenopausal women over 39 weeks . There was no change in strength in the HRT group. There were also no chan ges in leg strength at higher angular velocities or in grip strength for ei ther the post-menopausal group or those taking HRT. While HRT preserved mus cle strength, there was no evidence of a strengthening effect on skeletal m uscle within this short period of treatment. A rapid loss of leg strength o ccurs post-menopausally in hormone-depleted women. HRT may offer protection against muscle weakness, although the hormone responsible for regulating s trength is not evident using this model.