Purpose: Aging is commonly accompanied by progressive declines in skeletal muscle mass, muscle strength, and physical performance, which are associated with functional decline, disability, and reduced quality of life in older adults. The purpose of this study was to Creatine Supplementation during Suspension Training Reduces Circulating Myostatin Without Additional Improvements in Physical Function in Inactive Older Men: A Randomized Placebo-Controlled Trial.
Method: In this randomized, double-blind, placebo-controlled trial, 22 inactive older men aged 65–85 years were assigned to suspension training plus creatine (TRX+Cr; n = 11) or suspension training plus placebo (TRX+Pla; n = 11). Both groups completed a supervised 6-week suspension training program. The TRX+Cr group received creatine monohydrate at 0.3 g·kg⁻¹·day⁻¹ throughout the intervention, whereas the TRX+Pla group received placebo. Outcomes included appendicular skeletal muscle mass index (ASMI), serum myostatin, follistatin, insulin-like growth factor-1 (IGF-1), vitamin D, handgrip strength, five-times sit-to-stand (5xSTS), and Short Physical Performance Battery (SPPB). Between-group differences were analyzed using ANCOVA adjusted for baseline values.
Results: Creatine supplementation produced a greater reduction in circulating myostatin compared with placebo (p < 0.001). A significant between-group difference was also observed for follistatin (p = 0.002); however, this reflected a decrease in the creatine group and should not be interpreted as a favorable anabolic response. ASMI did not differ significantly between groups (p = 0.051). No significant between-group differences were observed for IGF-1, vitamin D, handgrip strength, 5xSTS, or SPPB.
Conclusion: Creatine supplementation during 6 weeks of suspension training reduced circulating myostatin in inactive older men, but this biomarker response was not accompanied by statistically significant additional improvements in ASMI, physical function, IGF-1, or vitamin D.