Protein ingestion increases myofibrillar protein synthesis after concurrent exercise

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Muscle Metabolism

Background:

• Concurrent training, combining resistance and endurance exercise, presents unique challenges for muscle adaptation.
• Understanding the role of post-exercise nutrition, specifically protein supplementation, is crucial for optimizing outcomes.
• Anabolic signaling pathways and protein synthesis rates are key indicators of muscle adaptation.

Purpose of the Study:

• To investigate the impact of post-exercise protein supplementation on anabolic signaling.
• To determine the effects on myofibrillar and mitochondrial protein synthesis rates following concurrent training.
• To examine the influence on muscle catabolism markers after a single bout of combined exercise.

Main Methods:

• Eight healthy males participated in a randomized crossover study.
• Concurrent training involved resistance exercise followed by cycling.
• Participants consumed either whey protein (PRO) or a placebo (PLA) post-exercise.
• Muscle biopsies were collected at rest and 1, 4 hours post-exercise.

Main Results:

• Protein supplementation significantly increased Akt and mTOR phosphorylation compared to placebo.
• Myofibrillar protein synthesis rates were elevated with protein intake.
• Markers of muscle catabolism (RING finger 1, atrogin-1 mRNA) were attenuated by protein supplementation.
• Mitochondrial protein synthesis did not show significant changes.

Conclusions:

• Concurrent training stimulates anabolic responses and increases metabolic gene expression.
• Post-exercise protein ingestion enhances myofibrillar protein synthesis and reduces muscle breakdown.
• Protein supplementation is a valuable nutritional strategy to improve adaptations to concurrent training.