Resistance exercise stimulates myofibrillar and muscle connective protein synthesis rates. Whey protein ingestion during post-exercise recovery further augments myofibrillar protein synthesis rates, but does not stimulate muscle connective protein synthesis rates. It has been suggested that collagen protein, due to its high glycine and proline contents, may be more effective in stimulating muscle connective protein synthesis rates during recovery from exercise. 

In a randomized, double-blind, parallel design, 45 young male and female recreational athletes (age: 25±4 y; BMI: 24.1±2.0 kg/m²) were selected to receive primed continuous intravenous infusions with L-[ring-¹³C₆]-phenylalanine and L-[3,5-²H₂]-tyrosine. Following a single session of resistance type exercise (6 sets of the barbell squat exercise), subjects were randomly allocated to one of three groups ingesting either 30 g whey protein (WHEY, n=15), 30 g collagen protein (COLL, n=15) or a non-caloric placebo (PLA, n=15). Blood and muscle biopsy samples were collected over a subsequent 5-hour recovery period to assess myofibrillar and muscle connective protein synthesis rates. 

Whey and collagen protein ingestion strongly increased circulating plasma amino acid concentrations when compared to the PLA group (P<0.05). The post-prandial rise in plasma leucine and total essential amino acid concentrations was greater in the WHEY compared with COLL group (P<0.05). In contrast, post-prandial plasma glycine, proline, and hydroxyproline concentrations increased to a greater extend in the COLL compared with WHEY group (P<0.05). Myofibrillar protein synthesis rates averaged 0.041±0.010, 0.036±0.010 and 0.032±0.007 %/h following whey, collagen, or placebo ingestion, respectively, with WHEY resulting in significant greater rates when compared with the PLA group (P<0.05). Muscle connective protein synthesis rates did not differ between groups (WHEY: 0.072±0.019, COLL: 0.068±0.017, PLA: 0.058±0.018 %/h; P=0.09).
Neither whey or collagen protein ingestion increase muscle connective protein synthesis rates during the early stages of post-exercise recovery in male and female recreational athletes.