scholarly journals Improving muscle mass: response of muscle metabolism to exercise, nutrition and anabolic agents

2008 ◽  
Vol 44 ◽  
pp. 85-98 ◽  
Author(s):  
Kevin D. Tipton ◽  
Arny A. Ferrando
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Creatine Supplementation ◽  
Healthy Weight ◽  
Anabolic Agents ◽  
Increase Muscle Mass ◽  
Positive Balance

Muscle mass is critical for athletic performance and, perhaps more importantly for most, health and survival. The metabolic basis for a change in muscle mass is an increase in net muscle protein balance (termed NBAL). NBAL is the difference between MPS (muscle protein synthesis) and MPB (muscle protein breakdown). Thus an increase in MPS and/or a decrease in MPB are necessary for NBAL to increase, leading to accretion of muscle proteins. In particular, accretion of myofibrillar proteins is necessary. NBAL responds to exercise, feeding and other factors. In healthy, weight-stable adults, muscle mass remains constant because periods of positive balance following feeding are countered by periods of negative balance during fasting. A combination of resistance exercise and nutrition is a potent anabolic stimulus through stimulation of MPS from amino acids and attenuation of MPB by carbohydrates. Increased muscle mass results from the accumulation of small amounts of protein in response to each bout of exercise combined with nutrient intake. The magnitude of the response may be influenced by factors other than just the amount of a nutrient ingested. Timing of ingestion, co-ingestion of nutrients and the type of protein may all influence protein accretion. Testosterone is a potent anabolic stimulus primarily through improvement in re-utilization of amino acids from MPB. There is a general lack of efficacy in studies assessing the potential for growth hormone, androstenedione and dehydroepiandrostenedione to increase muscle mass. Creatine supplementation is clearly an effective means to increase muscle mass, especially in combination with resistance exercise, however the mechanisms remain unclear. Results from acute metabolic studies provide useful information for estimation of the efficacy of anabolic agents.

scholarly journals The anabolic role of plant-based proteins in response to chronic resistance exercise

2021 ◽  
Vol 11 (3) ◽  
pp. 14-23
Author(s):  
Carina Sousa Santos ◽  
Eudes Souza Oliveira Júnior ◽  
Marcus James Lopes de Sá ◽  
Elizabethe Adriana Esteves
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
The Elderly ◽  
Food Sources ◽  
Dietary Adequacy ◽  
The Face

Proper maintenance of skeletal muscle mass is essential to prevent sarcopenia and ensure health and quality of life as aging progress. The two determinants of muscle protein synthesis are the increased load on skeletal muscle through resistance exercise and protein intake. For an effective result of maintaining or increasing muscle mass, it is relevant to consider the quantitative and adequate intake of protein, and the dietary source of protein since the plant-based protein has differences in comparison to animals that limit its anabolic capacity. Given the increase in vegetarianism and the elderly population, which consumes fewer food sources of animal protein, the importance of understanding how protein of plant-based protein can sustain muscle protein synthesis in the long term when associated with resistance exercise is justified, as well as the possibilities of dietary adequacy in the face of this demand.

The mechanistic and ergogenic effects of phosphatidic acid in skeletal muscle

2015 ◽  
Vol 40 (12) ◽  
pp. 1233-1241 ◽  
Author(s):  
Brandon James Shad ◽  
Benoit Smeuninx ◽  
Philip James Atherton ◽  
Leigh Breen
Keyword(s):  
Skeletal Muscle ◽  
Phosphatidic Acid ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Food Sources ◽  
Whole Body ◽  
Skeletal Muscle Protein

Skeletal muscle mass plays a vital role in locomotion, whole-body metabolic health, and is a positive predictor of longevity. It is well established the mammalian target of rapamycin (mTOR) is a central regulator of skeletal muscle protein turnover. The pursuit to find novel nutrient compounds or functional food sources that possess the ability to activate mTOR and promote skeletal muscle protein accretion has been on going. Over the last decade, a key role has been proposed for the phospholipid phosphatidic acid (PA) in mTOR activation. Mechanical load-induced (i.e., resistance exercise) intramuscular PA can directly bind to and activate mTOR. In addition, PA provided exogenously in cell culture heightens mTOR activity, albeit indirectly. Thus, endogenously generated PA and exogenous provision of PA appear to act through distinct mechanisms that converge on mTOR and, potentially, may amplify muscle protein synthesis. In support of this notion, limited evidence from humans suggests that resistance exercise training combined with oral supplemental PA enhances strength gains and muscle hypertrophy. However, the precise mechanisms underpinning the augmented muscle remodelling response with supplemental PA remain elusive. In this review, we will critically examine available evidence from cell cultures and animal and human experimental models to provide an overview of the mechanisms through which endogenous and exogenous PA may act to promote muscle anabolism, and discuss the potential for PA as a therapeutic tool to maintain or restore skeletal muscle mass in the context of ageing and disease.

Resistance exercise and nutrition to counteract muscle wasting

2009 ◽  
Vol 34 (5) ◽  
pp. 817-828 ◽  
Author(s):  
Jonathan P. Little ◽  
Stuart M. Phillips
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Effective Means ◽  
Resistance Exercise Training ◽  
Highly Effective

Loss of muscle mass is an unfavourable consequence of aging and many chronic diseases. The debilitating effects of muscle loss include declines in physical function and quality of life and increases in morbidity and mortality. Loss of muscle mass is the result of a decrease in muscle protein synthesis, an increase in muscle protein degradation, or a combination of both. Much research on muscle wasting has tended to focus on preventing muscle protein breakdown, and less attention has been paid to providing adequate stimulation to increase muscle protein synthesis. In this review, we present evidence to suggest that interventions aimed at increasing muscle protein synthesis represent the most effective countermeasure for preventing, delaying, or reversing the loss of skeletal muscle mass experienced in various muscle wasting conditions. Based on results from acute and chronic studies in humans in a wide variety of wasting conditions, we propose that resistance exercise training combined with appropriately timed protein (likely leucine-rich) ingestion represents a highly effective means to promote muscle hypertrophy, and may represent a highly effective treatment strategy to counteract the muscle wasting tassociated with aging and chronic disease.

Gaining Weight: The Scientific Basis of Increasing Skeletal Muscle Mass

1999 ◽  
Vol 24 (4) ◽  
pp. 305-316 ◽  
Author(s):  
Michael E. Houston
Keyword(s):  
Protein Synthesis ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Recovery Period ◽  
Scientific Basis ◽  
Whole Body ◽  
Anabolic Hormone

Most athletes today tend to have a larger muscle mass than their predecessors. Better training and nutrition practices are responsible for much of this difference, but whatever the mechanism, the balance between muscle protein synthesis and breakdown must be in favor of increased muscle protein. Applying new techniques for measuring whole body and muscle protein synthesis to resistance exercise has led to some interesting results. In the recovery period following resistance exercise, both muscle protein synthesis and breakdown are accelerated in the fasted state. Ingestion of carbohydrate or carbohydrate and protein during recovery further increases muscle protein synthesis, due in part to an improved anabolic hormone environment. In addition, the anabolic effect of a resistance training bout may last well beyond 48 hours. Using information obtained from research studies, better training and dietary practices can optimize the benefits from resistance training, Key words: protein synthesis, protein breakdown, anabolic hormones, nutrition, resistance training

scholarly journals Postexercise net protein synthesis in human muscle from orally administered amino acids

1999 ◽  
Vol 276 (4) ◽  
pp. E628-E634 ◽  
Author(s):  
Kevin D. Tipton ◽  
Arny A. Ferrando ◽  
Stuart M. Phillips ◽  
David Doyle ◽  
Robert R. Wolfe
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Random Order ◽  
Essential Amino Acids ◽  
Constant Infusion ◽  
Protein Balance

We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise. A primed, constant infusion ofl-[ ring-2H5]phenylalanine was used to measure net muscle protein balance in three male and three female volunteers on three occasions. Subjects consumed in random order 1 liter of 1) a mixed amino acid (40 g) solution (MAA), 2) an essential amino acid (40 g) solution (EAA), and 3) a placebo solution (PLA). Arterial amino acid concentrations increased ∼150–640% above baseline during ingestion of MAA and EAA. Net muscle protein balance was significantly increased from negative during PLA ingestion (−50 ± 23 nmol ⋅ min−1 ⋅ 100 ml leg volume−1) to positive during MAA ingestion (17 ± 13 nmol ⋅ min−1 ⋅ 100 ml leg volume−1) and EAA (29 ± 14 nmol ⋅ min−1 ⋅ 100 ml leg volume−1; P < 0.05). Because net balance was similar for MAA and EAA, it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise. We concluded that ingestion of oral essential amino acids results in a change from net muscle protein degradation to net muscle protein synthesis after heavy resistance exercise in humans similar to that seen when the amino acids were infused.

scholarly journals Amino Acid-Carbohydrate Intake Combined with Multiple Bouts of Resistance Exercise Increases Resting Energy Expenditure

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Kyle J. Hackney ◽  
Andrew R. Kelleher ◽  
Lori L. Ploutz-Snyder
Keyword(s):  
Amino Acids ◽  
Energy Expenditure ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Resting Energy Expenditure ◽  
Exercise Session ◽  
Energy Consuming ◽  
Resistance Exercise Session ◽  
Resting Energy

Increasing the rate of muscle protein synthesis is an energy consuming process that explains the acute elevations in resting energy expenditure (REE) observed 12 to 72 hours after a resistance exercise session. We hypothesized that multiple sessions of resistance exercise combined with the intake of amino acids would increase REE and alter the nonprotein respiratory exchange ratio (RER). Ten male participants completed two separate seven-day trials where REE and RER were measured on each morning via indirect calorimetry. On four consecutive days within each seven-day trial, acute resistance exercise was performed, and nutritional intake was manipulated by providing (1) amino acids and carbohydrate (AA-RT) or (2) nonnitrogenous, isoenergetic carbohydrate (CHO-RT) before and during each resistance exercise session. Average REE within the training period was 3.61% greater in AA-RT (7897 ± 252 kJ) compared to CHO-RT (7622 ± 289 kJ; P=0.02). RER declined (P<0.0001) from baseline after each resistance exercise was initiated in both AA-RT (0.82 ± 0.01 to 0.77 ± 0.01) and CHO-RT (0.82 ± 0.02 to 0.77 ± 0.02). We conclude the provision of amino acids with multiple bouts of resistance exercise enhances energy expenditure at rest without altering the utilization of lipid.

scholarly journals Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling

2009 ◽  
Vol 106 (4) ◽  
pp. 1374-1384 ◽  
Author(s):  
Micah J. Drummond ◽  
Hans C. Dreyer ◽  
Christopher S. Fry ◽  
Erin L. Glynn ◽  
Blake B. Rasmussen
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Human Skeletal Muscle ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Essential Amino Acids ◽  
Skeletal Muscle Protein ◽  
Mtorc1 Signaling

In this review we discuss current findings in the human skeletal muscle literature describing the acute influence of nutrients (leucine-enriched essential amino acids in particular) and resistance exercise on muscle protein synthesis and mammalian target of rapamycin complex 1 (mTORC1) signaling. We show that essential amino acids and an acute bout of resistance exercise independently stimulate human skeletal muscle protein synthesis. It also appears that ingestion of essential amino acids following resistance exercise leads to an even larger increase in the rate of muscle protein synthesis compared with the independent effects of nutrients or muscle contraction. Until recently the cellular mechanisms responsible for controlling the rate of muscle protein synthesis in humans were unknown. In this review, we highlight new studies in humans that have clearly shown the mTORC1 signaling pathway is playing an important regulatory role in controlling muscle protein synthesis in response to nutrients and/or muscle contraction. We propose that essential amino acid ingestion shortly following a bout of resistance exercise is beneficial in promoting skeletal muscle growth and may be useful in counteracting muscle wasting in a variety of conditions such as aging, cancer cachexia, physical inactivity, and perhaps during rehabilitation following trauma or surgery.

scholarly journals Essential amino acids and muscle protein recovery from resistance exercise

2002 ◽  
Vol 283 (4) ◽  
pp. E648-E657 ◽  
Author(s):  
Elisabet Børsheim ◽  
Kevin D. Tipton ◽  
Steven E. Wolf ◽  
Robert R. Wolfe
Keyword(s):  
Amino Acids ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Vastus Lateralis ◽  
Area Under The Curve ◽  
Essential Amino Acids ◽  
Constant Infusion ◽  
Protein Balance ◽  
Dose Dependent

This study tests the hypothesis that a dose of 6 g of orally administered essential amino acids (EAAs) stimulates net muscle protein balance in healthy volunteers when consumed 1 and 2 h after resistance exercise. Subjects received a primed constant infusion ofl-[2H5]phenylalanine andl-[1-13C]leucine. Samples from femoral artery and vein and biopsies from vastus lateralis were obtained. Arterial EAA concentrations increased severalfold after drinks. Net muscle protein balance (NB) increased proportionally more than arterial AA concentrations in response to drinks, and it returned rapidly to basal values when AA concentrations decreased. Area under the curve for net phenylalanine uptake above basal value was similar for the first hour after each drink (67 ± 17 vs. 77 ± 20 mg/leg, respectively). Because the NB response was double the response to two doses of a mixture of 3 g of EAA + 3 g of nonessential AA (NEAA) (14), we conclude that NEAA are not necessary for stimulation of NB and that there is a dose-dependent effect of EAA ingestion on muscle protein synthesis.

scholarly journals How to Overcome Anabolic Resistance in Dialysis-Treated Patients?

2021 ◽  
Vol 8 ◽  
Author(s):  
Giacomo Garibotto ◽  
Michela Saio ◽  
Francesca Aimasso ◽  
Elisa Russo ◽  
Daniela Picciotto ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Muscle Mass ◽  
Healthy Subjects ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Optimal Dose ◽  
Dialysis Patients ◽  
Protein Amino Acid ◽  
Anabolic Resistance

A current hypothesis is that dialysis-treated patients are “anabolic resistant” i. e., their muscle protein synthesis (MPS) response to anabolic stimuli is blunted, an effect which leads to muscle wasting and poor physical performance in aging and in several chronic diseases. The importance of maintaining muscle mass and MPS is often neglected in dialysis-treated patients; better than to describe mechanisms leading to energy-protein wasting, the aim of this narrative review is to suggest possible strategies to overcome anabolic resistance in this patient's category. Food intake, in particular dietary protein, and physical activity, are the two major anabolic stimuli. Unfortunately, dialysis patients are often aged and have a sedentary behavior, all conditions which per se may induce a state of “anabolic resistance.” In addition, patients on dialysis are exposed to amino acid or protein deprivation during the dialysis sessions. Unfortunately, the optimal amount and formula of protein/amino acid composition in supplements to maximixe MPS is still unknown in dialysis patients. In young healthy subjects, 20 g whey protein maximally stimulate MPS. However, recent observations suggest that dialysis patients need greater amounts of proteins than healthy subjects to maximally stimulate MPS. Since unneccesary amounts of amino acids could stimulate ureagenesis, toxins and acid production, it is urgent to obtain information on the optimal dose of proteins or amino acids/ketoacids to maximize MPS in this patients' population. In the meantime, the issue of maintaining muscle mass and function in dialysis-treated CKD patients needs not to be overlooked by the kidney community.

scholarly journals Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging

2008 ◽  
Vol 104 (5) ◽  
pp. 1452-1461 ◽  
Author(s):  
Micah J. Drummond ◽  
Hans C. Dreyer ◽  
Bart Pennings ◽  
Christopher S. Fry ◽  
Shaheen Dhanani ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Essential Amino Acids ◽  
Skeletal Muscle Protein ◽  
Eif2α Phosphorylation ◽  
Increased Risk ◽  
Old Men

Skeletal muscle loss during aging leads to an increased risk of falls, fractures, and eventually loss of independence. Resistance exercise is a useful intervention to prevent sarcopenia; however, the muscle protein synthesis (MPS) response to resistance exercise is less in elderly compared with young subjects. On the other hand, essential amino acids (EAA) increase MPS equally in both young and old subjects when sufficient EAA is ingested. We hypothesized that EAA ingestion following a bout of resistance exercise would stimulate anabolic signaling and MPS similarly between young and old men. Each subject ingested 20 g of EAA 1 h following leg resistance exercise. Muscle biopsies were obtained before and 1, 3, and 6 h after exercise to measure the rate of MPS and signaling pathways that regulate translation initiation. MPS increased early in young (1–3 h postexercise) and later in old (3–6 h postexercise). At 1 h postexercise, ERK1/2 MNK1 phosphorylation increased and eIF2α phosphorylation decreased only in the young. mTOR signaling (mTOR, S6K1, 4E-BP1, eEF2) was similar between groups at all time points, but MNK1 phosphorylation was lower at 3 h and AMP-activated protein kinase-α (AMPKα) phosphorylation was higher in old 1–3 h postexercise. We conclude that the acute MPS response after resistance exercise and EAA ingestion is similar between young and old men; however, the response is delayed with aging. Unresponsive ERK1/2 signaling and AMPK activation in old muscle may be playing a role in the delayed activation of MPS. Notwithstanding, the combination of resistance exercise and EAA ingestion should be a useful strategy to combat sarcopenia.

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