The effects of carbohydrate and protein supplementation on signaling pathways regulating protein turnover and muscle mass following chronic resistance training

Skeletal muscle is important for physical activity and regulation of metabolism. Increase or maintenance of muscle mass is pursued by different populations ranging from athletes to people suffering from severe muscular diseases causing muscle atrophy/wasting. In this study, four animal groups were generated: sedentary group (No supplements or exercise) (SED); resistance training (RE) and whey supplements (WP); RE and combo (Carbohydrate and whey) supplements (CP); RE and placebo (DI water) (PLA). Flexor hallucis longus (FHL) muscles were collected after 8 weeks of training. Expression of several key proteins controlling muscle mass and protein turnover were measured in order to compare how different combinations affect muscle growth. It was found that resistance training induced reductions in myostatin protein expression compared with sedentary controls (p<0.05) and that MuRF was elevated in the CP group compared with sedentary group (p<0.05). We conclude that resistance training may upregulate protein synthesis through suppressing myostatin and that resistance training may increase muscle protein breakdown.