Postinactivity Exercise Training Improves Sarcopenia Traits in 40-60-Year-Old Women Regardless of Fortified Milk...

The term sarcopenia was introduced to describe the age-related decline in muscle mass, but current definitions also include measures of muscle strength and function. Menopause increases sarcopenia risk and may exacerbate the adverse effects of physical inactivity. Exercise training is a potent stimulus to restore muscle health, and nutritional supplementation can further improve the outcomes. The purposes of this study were to examine the changes in a set of sarcopenia-related phenotypes induced by a 14-day step-reduction period followed by a 12-week exercise training programme, with or without fortified milk supplementation in healthy 40-60-year-old females, and to determine whether menopausal status interacted with these changes.

In this double-blind, placebo-controlled randomized trial, females aged 40-60 years were evaluated before and after 2 weeks of reduced activity monitored through pedometer and after a subsequent 12-week exercise + nutrition programme with ingestion of a fortified milk product (FMP) or placebo. Muscle volume (dual-energy X-ray absorptiometry [DXA] and peripheral quantitative computed tomography), handgrip (hydraulic handheld dynamometer), knee extensor and plantar flexor strength (isokinetic dynamometer) and a variety of physical function measures were assessed at all timepoints.

Eighty-three self-reported healthy females (50.7 ± 5.3 years; 52 postmenopausal) completed the reduced-activity period, and 67 completed the subsequent exercise training + nutrition phase. At baseline, participants averaged 8323 ± 3077 daily steps and then decreased to 1876 ± 729 during the reduced-activity period. Mean sarcopenia outcomes declined after 2 weeks of activity restriction, with significant changes (p < 0.05) in shank muscle cross-sectional area (CSA) (67.7 ± 9.9 to 66.5 ± 9.9 cm²), handgrip strength (25.3 ± 5.0 to 24.0 ± 5.3 kg), knee extensor peak torque (134.7 ± 36.2 to 122.7 ± 34.5 Nm) and stair ascending time (3.6 ± 0.6 to 3.7 ± 0.6 s) and power (367.6 ± 67.6 to 356.7 ± 67.7 W), with no significant time × menopause interactions (p > 0.05 for all variables). All muscle mass, strength and function outcomes were not only improved after exercise training + nutrition but also significantly increased compared to preintervention baseline (all p < 0.05). No training × menopause or training × supplementation interactions were observed for any variable (both p > 0.05).

Two weeks of step reduction negatively affected muscle mass, strength and physical function in 40-60-year-old females. A 12-week training programme including strength exercises and dietary supplementation not only recovered muscular health but also promoted improvements above the baseline before the physical activity restriction. Menopause status did not influence changes in response to step reduction or exercise, and the addition of a fortified milk product during the training period did not influence the induced adaptations.