Effects of BFR-training on Stem Cells and Immune Cells in Human Skeletal Muscle

In this 3-year project, investigators will first measure stem cells (primary outcome) and immune cells (secondary outcome) in human skeletal muscle immediately after and 24 hour after the BFR-training. In the second and third year, the effect of β-NMN (vitamin B3 precursor) and antioxidant on the same outcomes after BFR-exercise will be assessed. The BFR-exercise in the study will consist of a 5 × 10-second sprinting with maximal voluntary efforts, 5 minutes after a BFR pre-conditioning to legs using pressurized cuffs. In Study 1 (1st year, N = 24, aged 20-30 year), a randomized crossover trial will be conducted to compare the efficacy of sprinting exercise using BFR pre-conditioning at 20 mmHg (control) or 180 mmHg (occlusion). Study 2 (2nd year, N = 24, aged 20-30 years) will be conducted to examine the effect of β-NMN supplementation on the aforementioned outcomes in human muscles using a randomized placebo-controlled crossover study design. Study 3 (third year, N = 24, aged 20-30 years) will be conducted to examine the effect of vitamin C on the same variables immediately after and 24 hours after resistance exercise intervention, using a randomized placebo-controlled crossover study design.