The impact of whey versus collagen protein ingestion on post-exercise myofibrillar and connective tissue protein synthesis rates

Protein ingestion stimulates muscle protein synthesis and augments the muscle protein synthetic response to a single exercise session. In support, protein supplementation has been shown to augment the gains in muscle mass and strength following resistance exercise training. The force generated by contracting muscle is transferred through a network of collagenous connective tissue proteins to articulate the bone. Therefore, the remodelling of skeletal muscle connective tissue represents an essential component of muscle adaptation to exercise. A single exercise session increases muscle connective tissue protein synthesis rates. However, the impact of protein ingestion to augment post-exercise connective tissue protein synthesis rate remains to be established. Whey protein is considered the preferred protein source to maximize myofibrillar protein synthesis rates. However, whey protein contains insufficient glycine and proline to support the post-exercise increase in connective tissue protein synthesis rates. In contrast, dietary collagen protein is rich in glycine and proline and has, therefore, been proposed as a preferred protein source to support connective tissue remodelling.

1. We hypothesize that post exercise whey protein ingestion will increase myofibrillar protein synthesis rates to a greater extent than collagen protein supplementation.
2. We hypothesize that post exercise collagen protein ingestion will increase connective tissue protein synthesis rates to a greater extent than whey protein supplementation.
3. We hypothesize that collagen ingestions will result in greater post-exercise plasma concentrations of glycine and proline, whereas whey ingestion will result in greater post-exercise plasma leucine concentration.

Muscle biopsies will be taken at timepoints: 0 (after exercise and before the beverage) and 5 h after ingestion of the beverage.

All subjects will perform an exercise bout of barbell squats. Immediately following exercise, subjects will be randomly assigned to ingest a beverage (500 mL) containing either 30 g whey protein, 30 g collagen protein or non-caloric flavoured water (n=15 per group).