Protein Intake Critical for Muscle Growth…
Muscle is in a constant state of synthesis and breakdown, and requires adequate protein intake to maintain size— even when overloaded through weight training. Amino acids that make up proteins serve as chemical signalers and building blocks for muscle proteins.
Dan Weinert from the Palmer College of Chiropractic in Iowa summarized how protein influences muscle protein synthesis. Timing protein intake is critical for muscle protein synthesis. Weight trainers should consume excess protein within three hours of weight training. Leucine is the key amino acid for turning on muscle protein synthesis via the mTOR pathway, but muscle hypertrophy grinds to a halt without the full complement of essential amino acids.
Following intense resistance exercise, muscle protein synthesis occurs in direct proportion to protein intake, peaking at 20-40 grams. People over 40 years are less responsive to key amino acids, so they should consume protein often during the day to maintain muscle mass and prevent atrophy (muscle breakdown). Older adults should combine weight training and adequate protein intake to preserve muscle mass as they age. (Journal Canadian Chiropractic Association, 53: 186-193, 2009)
