Resistance training increases muscle volume and strength in postmenopausal women with hot flushes

OBJECTIVES: To investigate changes in muscle volume and muscular fat infiltration in postmenopausal women after 15 weeks of resistance training compared with a control group with an unchanged low level of physical activity. We also assessed whether the intervention group increased their muscle strength. STUDY DESIGN: This study was a secondary analysis of a randomised controlled trial on the effects of resistance training in postmenopausal women. Women with hot flushes (n = 65) were randomised to supervised resistance training three times per week for 15 weeks or to a control group. MAIN OUTCOME MEASURES: Muscle strength in the intervention group was measured with 8-repetition maximum tests. At baseline and after 15 weeks, 44 subjects were scanned with a 3.0 T magnetic resonance scanner using a whole-body Dixon protocol. A semi-automated method was used for calculation of muscle volume and muscle fat infiltration. RESULTS: Significant between-groups differences were seen in change of muscle volume (p < 0.001-0.015) between the intervention and control group from baseline to 15 weeks. Muscle volume increased by about 4 % (p < 0.001) for all muscles in the intervention group, whereas no change was seen in the control group. Muscle strength increased significantly in the intervention group for all tested muscles. Muscle fat infiltration did not change. CONCLUSION: Postmenopausal women with hot flushes and a low level of physical activity could, in just 15 weeks, increase their muscle volume and strength through resistance training. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01987778.