The effects of oral creatine (Cr) supplementation on muscle contractile performance and metabolism of skeletal muscle recently have become an area of major interest in exercise physiology. Creatine not only increases workout performance but also has recently been shown to increase muscle hypertrophy through activation of satellite cell activity and increasing mRNA IGF-1 activity. Another added benefit of creatine is that it may also reduce post-exercise inflammation and muscle damage. The term “repeated bout effect” is used to refer to the ameliorative effect of a previous resistance-training bout on the muscle damage (usually measured by creatine kinase leakage from the muscle) on a second workout. Researchers from Brazil have now shown that creatine can amplify the protective effect of previous workouts. They therefore recruited 18 healthy young male subjects and randomly assigned the subjects into either creatine or placebo groups. Subjects performed two resistance-training sessions, each protocol involving four sets of barbell biceps curls to concentric failure using 75% of 1RM, with three minutes of rest between sets and a controlled cadence of four seconds per rep (two seconds concentric and two seconds eccentric). Prior to the second test, the subjects consumed either 5g of creatine monohydrate with glucose four times per day or placebo supplements four times per day for six consecutive days. At the end of the study, muscle soreness was significantly increased in both groups after the first training session. After the second session, both groups displayed less soreness, however the reduction in soreness was greater in the creatine supplementation group. Additionally, markers of muscle damage measured (i.e., creatine kinase) were lesser after creatine supplementation; the researchers concluded that creatine provides an additive effect on blunting the rise of muscle damage markers following a repeated bout of resistance exercise. Creatine may have antioxidant properties which can have protective effects on muscle damage.
Another added benefit of creatine is that it may also reduce post-exercise inflammation and muscle damage. – FLEX
