“Skeletal Muscle Protein Synthetic Response to Amino Acid and Peptides”
Skeletal muscle quality is an important determinant of exercise performance and overall health. It is vital for not just movement, but also metabolizing nutrients. Protein from the diet can promote muscle protein synthesis for muscle recovery and growth. More importantly, doing so shifts net protein balance positively (e.g. protein synthesis is greater than protein breakdown) and promotes greater rates of muscle protein turnover. Leucine is an amino acid required to build muscle, but it also acts as a signaling molecule informing the muscle to start protein synthesis. Before reaching skeletal muscle, dietary protein is digested into small peptides and free amino acids. Rate of absorption from the intestine to the blood stream is significantly faster for peptides compared to amino acids. As amino acid availability in the blood is a precursor for muscle protein synthesis, our objective is to determine if the different absorption rates between free amino acid and peptides influence muscle protein synthetic and breakdown rates.
Behavioral - Resistance Exercise
Prior to protein consumption participants will perform an acute bout of resistance exercise. They will warm up with two sets of 10 repetitions at 35-75% working load respectively, then perform four working sets of 10-12 repetitions at 65-70% of 1-RM. 1 min, 30 sec rest periods will be implemented between each set.
Behavioral - No Resistance Exercise
Participants allocated to this group will not perform exercise prior to the administration of the nutritional intervention. Participants will remain at rest throughout the trial.
Dietary Supplement - Leucine
Participants will be given 2g of leucine dissolved in 250mL of water. Drink will be consumed immediately after exercise or equivalent time point for non-exercise group.
Dietary Supplement - Dileucine
Participants will be given 2g of dileucine dissolved in 250mL of water. Drink will be consumed immediately after exercise or equivalent time point for non-exercise group.
Skeletal Muscle Protein Synthetic Response to Amino Acid and Peptides