Effect of Schisandra chinensis Baillon extracts and regular low-intensity exercise on muscle strength and mass in older adults: a randomized, double-blind, placebo-controlled trial.

BACKGROUND Studies suggest that Schisandra chinensis Baillon (Sc) may enhance muscle strength and mass because of its anti-inflammatory and antioxidant properties. OBJECTIVES We aimed to examine the effects and safety of consumption of Sc extract (SCe) for 12 wk on muscle strength and mass in older adults with relatively low muscle mass who do low-intensity exercise. METHODS A randomized, double-blind, placebo-controlled trial was performed in adults >50 y of age. Fifty-four participants were randomly assigned into 2 groups and, for 12 wk, received either 1 g SCe/d or a placebo. All participants were required to walk for 30-60 min/d for >3 d/wk during the trial period. At baseline and at 4 and 12 wk after treatment, the participants were examined for knee extension strength using Biodex isokinetic dynamometers, handgrip strengths, and body composition, and blood tests were performed. The Euro-QoL-5D (EQ-5D) questionnaire and the FFQ were administered at baseline and at 12 wk after treatment. Physical activity was assessed using a self-recorded daily exercise log and an accelerometer during the study. RESULTS SCe supplementation over 12 wk caused a higher increase in right knee extensor strength by 10.2 Nm (95% CI: 3.7, 16.8 Nm; P = 0.003) and left knee extensor strength by 6.7 Nm (95% CI: 0.3, 13.1 Nm; P = 0.041) than did the placebo. However, no differences were observed in the muscle mass, anti-inflammatory markers, antioxidative markers, and EQ-5D score between the groups. None of the participants experienced adverse events. CONCLUSIONS SCe supplementation may enhance skeletal muscle strength but not mass in older adults who perform low-intensity exercise. This trial was registered at clinicaltrials.gov as NCT03402308.