The Effect of Whey Protein Supplementation on Myofibrillar Protein Synthesis and Performance Recovery in Resistance-Trained Men
Robert W. Davies, Joseph J. Bass, Brian P. Carson, Catherine Norton, Marta Kozior, Daniel J. Wilkinson, Matthew S. Brook, Philip J. Atherton, Kenneth Smith, Philip M. Jakeman
Abstract
Background: The aim of this study was to investigate the effect of whey protein supplementation on myofibrillar protein synthesis (myoPS) and muscle recovery over a 7-d period of intensified resistance training (RT). Methods: In a double-blind randomised parallel group design, 16 resistance-trained men aged 18 to 35 years completed a 7-d RT protocol, consisting of three lower-body RT sessions on non-consecutive days. Participants consumed a controlled diet (146 kJ·kg−1·d−1, 1.7 g·kg−1·d−1 protein) with either a whey protein supplement or an isonitrogenous control (0.33 g·kg−1·d−1 protein). To measure myoPS, 400 ml of deuterium oxide (D2O) (70 atom %) was ingested the day prior to starting the study and m. vastus lateralis biopsies were taken before and after RT-intervention. Myofibrillar fractional synthetic rate (myoFSR) was calculated via deuterium labelling of myofibrillar-bound alanine, measured by gas chromatography-pyrolysis-isotope ratio mass spectrometry (GC-Pyr-IRMS). Muscle recovery parameters (i.e., countermovement jump height, isometric-squat force, muscle soreness and serum creatine kinase) were assessed daily. Results: MyoFSR PRE was 1.6 (0.2) %∙d−1 (mean (SD)). Whey protein supplementation had no effect on myoFSR (p = 0.771) or any recovery parameter (p = 0.390–0.989). Conclusions: Over an intense 7-d RT protocol, 0.33 g·kg−1·d−1 of supplemental whey protein does not enhance day-to-day measures of myoPS or postexercise recovery in resistance-trained men.