Muscle protein synthesis (MPS) is the metabolic process that describes the incorporation of amino acids into bound skeletal muscle proteins. Muscle proteins can be crudely classified into the contractile myofibrillar proteins (i.e., myosin, actin, tropomyosin, troponin) and the energy producing
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Making Sense of Muscle Protein Synthesis: A Focus on Muscle Growth During Resistance Training
Oliver C. Witard, Laurent Bannock, and Kevin D. Tipton
Celebrating the Professional Life of Professor Kevin D. Tipton (1961–2022)
Oliver C. Witard, Arny A. Ferrando, and Stuart M. Phillips
Stimulates Net Muscle Protein Synthesis Following Resistance Exercise” ( Elliot et al., 2006 ). The results from that paper still intrigue many today as to the mechanism underlying milk’s anabolic properties. While that publication may have been the first, it was most certainly not the last of Kevin’s senior
The Anabolic Response to Protein Ingestion During Recovery From Exercise Has No Upper Limit in Magnitude and Duration In Vivo in Humans: A Commentary
Oliver C. Witard and Samuel Mettler
,” recreationally active (but not resistance-trained), young men following resistance exercise. Moreover, this study demonstrated that the duration of the postprandial period is modulated by the dose of ingested protein contained within a meal, that is, the postexercise muscle protein synthesis (MPS) response to
No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise
Mark Messina, Heidi Lynch, Jared M. Dickinson, and Katharine E. Reed
monitoring changes in muscle protein synthesis (MPS) over a 3- to 4-hr period. To the authors’ knowledge, seven such studies ( Gran et al., 2014 ; Luiking et al., 2011 ; Mitchell et al., 2015 ; Rittig et al., 2017 ; Tang et al., 2009 ; Wilkinson et al., 2007 ; Yang et al., 2012a ) involving both
Exercise, Protein Metabolism, and Muscle Growth
Kevin D. Tipton and Robert R. Wolfe
Exercise has a profound effect on muscle growth, which can occur only if muscle protein synthesis exceeds muscle protein breakdown; there must be a positive muscle protein balance. Resistance exercise improves muscle protein balance, but, in the absence of food intake, the balance remains negative (i.e., catabolic). The response of muscle protein metabolism to a resistance exercise bout lasts for 24-48 hours; thus, the interaction between protein metabolism and any meals consumed in this period will determine the impact of the diet on muscle hypertrophy. Amino acid availability is an important regulator of muscle protein metabolism. The interaction of postexercise metabolic processes and increased amino acid availability maximizes the stimulation of muscle protein synthesis and results in even greater muscle anabolism than when dietary amino acids are not present. Hormones, especially insulin and testosterone, have important roles as regulators of muscle protein synthesis and muscle hypertrophy. Following exercise, insulin has only a permissive role on muscle protein synthesis, but it appears to inhibit the increase in muscle protein breakdown. Ingestion of only small amounts of amino acids, combined with carbohydrates, can transiently increase muscle protein anabolism, but it has yet to be determined if these transient responses translate into an appreciable increase in muscle mass over a prolonged training period.
Protein Intake Distribution: Beneficial, Detrimental, or Inconsequential for Muscle Anabolism? Response to Witard & Mettler
Jorn Trommelen, Andrew M. Holwerda, and Luc J.C. van Loon
concept. Much work has investigated the impact of protein intake distribution on muscle protein synthesis or muscle mass. These studies typically compare the impact of meal frequency (e.g., 40 g protein consumed every 6 hr vs. 20 g protein consumed every 3 hr), the impact of distribution pattern within
Coingestion of Collagen With Whey Protein Prevents Postexercise Decline in Plasma Glycine Availability in Recreationally Active Men
Thorben Aussieker, Tom A.H. Janssen, Wesley J.H. Hermans, Andrew M. Holwerda, Joan M. Senden, Janneau M.X. van Kranenburg, Joy P.B. Goessens, Tim Snijders, and Luc J.C. van Loon
Exercise increases muscle protein synthesis rates ( Biolo et al., 1995 ). This includes substantial increases in both myofibrillar ( Wilkinson et al., 2008 ) and muscle connective protein ( Holm et al., 2010 ; Holwerda et al., 2021 ; Trommelen et al., 2020 ) synthesis rates. Whereas the impact of
Isolated Leucine and Branched-Chain Amino Acid Supplementation for Enhancing Muscular Strength and Hypertrophy: A Narrative Review
Daniel L. Plotkin, Kenneth Delcastillo, Derrick W. Van Every, Kevin D. Tipton, Alan A. Aragon, and Brad J. Schoenfeld
& Brosnan, 2006 ). Of the three BCAA, leucine is most notably a key regulator of muscle protein synthesis (MPS), exerting modulating effects even in the presence of hyperaminoacidemia ( Rieu et al., 2006 ). Much of the early data on BCAA supplementation came from rodent studies. These studies suggested that
The Postprandial Plasma Amino Acid Response Does Not Differ Following the Ingestion of a Solid Versus a Liquid Milk Protein Product in Healthy Adult Females
Glenn A.A. van Lieshout, Jorn Trommelen, Jean Nyakayiru, Janneau van Kranenburg, Joan M. Senden, Lex B. Verdijk, and Luc J.C. van Loon
It has been well-established that protein ingestion increases muscle protein synthesis rates ( Biolo et al., 1997 ; Trommelen et al., 2019 ). The postprandial rise in muscle protein synthesis plays a key role in muscle maintenance and is instrumental in supporting the skeletal muscle adaptive
Exercise Plus Presleep Protein Ingestion Increases Overnight Muscle Connective Tissue Protein Synthesis Rates in Healthy Older Men
Andrew M. Holwerda, Jorn Trommelen, Imre W.K. Kouw, Joan M. Senden, Joy P.B. Goessens, Janneau van Kranenburg, Annemie P. Gijsen, Lex B. Verdijk, and Luc J.C. van Loon
stiffness ( Wood et al., 2014 ), which contribute to the age-related decline in muscle strength and functional capacity ( Azizi et al., 2017 ; Kragstrup et al., 2011 ). Skeletal muscle tissue (mal)adaptation is regulated by the net balance between muscle protein synthesis and breakdown rates, with a tissue
