title: The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein.
abstract: The currently accepted amount of protein required to achieve maximal stimulation of myofibrillar protein synthesis (MPS) following resistance exercise is 20-25 g. However, the influence of lean body mass (LBM) on the response of MPS to protein ingestion is unclear. Our aim was to assess the influence of LBM, both total and the amount activated during exercise, on the maximal response of MPS to ingestion of 20 or 40 g of whey protein following a bout of whole-body resistance exercise. Resistance-trained males were assigned to a group with lower LBM (≤65 kg; LLBM n = 15) or higher LBM (≥70 kg; HLBM n = 15) and participated in two trials in random order. MPS was measured with the infusion of (13)C6-phenylalanine tracer and collection of muscle biopsies following ingestion of either 20 or 40 g protein during recovery from a single bout of whole-body resistance exercise. A similar response of MPS during exercise recovery was observed between LBM groups following protein ingestion (20 g - LLBM: 0.048 ± 0.018%·h(-1); HLBM: 0.051 ± 0.014%·h(-1); 40 g - LLBM: 0.059 ± 0.021%·h(-1); HLBM: 0.059 ± 0.012%·h(-1)). Overall (groups combined), MPS was stimulated to a greater extent following ingestion of 40 g (0.059 ± 0.020%·h(-1)) compared with 20 g (0.049 ± 0.020%·h(-1); P = 0.005) of protein. Our data indicate that ingestion of 40 g whey protein following whole-body resistance exercise stimulates a greater MPS response than 20 g in young resistance-trained men. However, with the current doses, the total amount of LBM does not seem to influence the response.
authors: Health and Exercise Sciences Research Group, University of Stirling, Stirling, Scotland.
authors: Lindsay S
authors: LS
authors: Macnaughton
authors: Health and Exercise Sciences Research Group, University of Stirling, Stirling, Scotland.
authors: Sophie L
authors: SL
authors: Wardle
authors: Health and Exercise Sciences Research Group, University of Stirling, Stirling, Scotland.
authors: Oliver C
authors: OC
authors: Witard
authors: Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors: Chris
authors: C
authors: McGlory
authors: Health and Exercise Sciences Research Group, University of Stirling, Stirling, Scotland.
authors: D Lee
authors: DL
authors: Hamilton
authors: Health and Exercise Sciences Research Group, University of Stirling, Stirling, Scotland.
authors: Stewart
authors: S
authors: Jeromson
authors: GlaxoSmithKline Consumer Healthcare, Brentford, UK.
authors: Clare E
authors: CE
authors: Lawrence
authors: School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.
authors: Gareth A
authors: GA
authors: Wallis
authors: Health and Exercise Sciences Research Group, University of Stirling, Stirling, Scotland k.d.tipton@stir.ac.uk.
authors: Kevin D
authors: KD
authors: Tipton
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000097:blood; D001837:Body Weights and Measures; D015444:Exercise; D006801:Humans; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000378:metabolism; D009210:Myofibrils / Q000378:metabolism*; D010649:Phenylalanine / Q000378:metabolism; D014508:Urea / Q000097:blood; D000067816:Whey Proteins / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D000596:Amino Acids; D009124:Muscle Proteins; D000067816:Whey Proteins; D010649:Phenylalanine; D014508:Urea
keywords: Fractional synthesis rate; intracellular signaling proteins; lean body mass; protein dose‐response