Resistance exercise and the mechanisms of muscle mass regulation in humans: Acute effects on muscle protein turnover and the gaps in our understanding of chronic resistance exercise training adaptation

2013 ◽  
Vol 45 (10) ◽  
pp. 2209-2214 ◽  
Author(s):  
A.J. Murton ◽  
P.L. Greenhaff
Keyword(s):  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Acute Effects ◽  
Resistance Exercise Training ◽  
Muscle Protein Turnover ◽  
Training Adaptation

scholarly journals Myostatin Inhibition-Induced Increase in Muscle Mass and Strength Was Amplified by Resistance Exercise Training, and Dietary Essential Amino Acids Improved Muscle Quality in Mice

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1508
Author(s):  
Jiwoong Jang ◽  
Sanghee Park ◽  
Yeongmin Kim ◽  
Jiyeon Jung ◽  
Jinseok Lee ◽  
...  
Keyword(s):  
Amino Acids ◽  
Muscle Mass ◽  
Mitochondrial Biogenesis ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Essential Amino Acids ◽  
Muscle Quality ◽  
Resistance Exercise Training ◽  
Muscle Protein Turnover ◽  
Myostatin Inhibition

It has been frequently reported that myostatin inhibition increases muscle mass, but decreases muscle quality (i.e., strength/muscle mass). Resistance exercise training (RT) and essential amino acids (EAAs) are potent anabolic stimuli that synergistically increase muscle mass through changes in muscle protein turnover. In addition, EAAs are known to stimulate mitochondrial biogenesis. We have investigated if RT amplifies the anabolic potential of myostatin inhibition while EAAs enhance muscle quality through stimulations of mitochondrial biogenesis and/or muscle protein turnover. Mice were assigned into ACV (myostatin inhibitor), ACV+EAA, ACV+RT, ACV+EAA +RT, or control (CON) over 4 weeks. RT, but not EAA, increased muscle mass above ACV. Despite differences in muscle mass gain, myofibrillar protein synthesis was stimulated similarly in all vs. CON, suggesting a role for changes in protein breakdown in muscle mass gains. There were increases in MyoD expression but decreases in Atrogin-1/MAFbx expression in ACV+EAA, ACV+RT, and ACV+EAA+RT vs. CON. EAA increased muscle quality (e.g., grip strength and maximal carrying load) without corresponding changes in markers of mitochondrial biogenesis and neuromuscular junction stability. In conclusion, RT amplifies muscle mass and strength through changes in muscle protein turnover in conjunction with changes in implicated signaling, while EAAs enhance muscle quality through unknown mechanisms.

scholarly journals Preserved Capacity for Adaptations in Strength and Muscle Regulatory Factors in Elderly in Response to Resistance Exercise Training and Deconditioning

2020 ◽  
Vol 9 (7) ◽  
pp. 2188 ◽  
Author(s):  
Andreas Mæchel Fritzen ◽  
Frank D. Thøgersen ◽  
Khaled Abdul Nasser Qadri ◽  
Thomas Krag ◽  
Marie-Louise Sveen ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Myogenic Regulatory Factors ◽  
Resistance Exercise Training ◽  
Regulatory Factors ◽  
Age Related ◽  
Muscle Regulatory Factors

Aging is related to an inevitable loss of muscle mass and strength. The mechanisms behind age-related loss of muscle tissue are not fully understood but may, among other things, be induced by age-related differences in myogenic regulatory factors. Resistance exercise training and deconditioning offers a model to investigate differences in myogenic regulatory factors that may be important for age-related loss of muscle mass and strength. Nine elderly (82 ± 7 years old) and nine young, healthy persons (22 ± 2 years old) participated in the study. Exercise consisted of six weeks of resistance training of the quadriceps muscle followed by eight weeks of deconditioning. Muscle biopsy samples before and after training and during the deconditioning period were analyzed for MyoD, myogenin, insulin-like growth-factor I receptor, activin receptor IIB, smad2, porin, and citrate synthase. Muscle strength improved with resistance training by 78% (95.0 ± 22.0 kg) in the elderly to a similar extent as in the young participants (83.5%; 178.2 ± 44.2 kg) and returned to baseline in both groups after eight weeks of deconditioning. No difference was seen in expression of muscle regulatory factors between elderly and young in response to exercise training and deconditioning. In conclusion, the capacity to gain muscle strength with resistance exercise training in elderly was not impaired, highlighting this as a potent tool to combat age-related loss of muscle function, possibly due to preserved regulation of myogenic factors in elderly compared with young muscle.

scholarly journals Influence of acetaminophen and ibuprofen on skeletal muscle adaptations to resistance exercise in older adults

2011 ◽  
Vol 300 (3) ◽  
pp. R655-R662 ◽  
Author(s):  
Todd A. Trappe ◽  
Chad C. Carroll ◽  
Jared M. Dickinson ◽  
Jennifer K. LeMoine ◽  
Jacob M. Haus ◽  
...  
Keyword(s):  
Older Adults ◽  
Resistance Training ◽  
Muscle Strength ◽  
Exercise Training ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Drug Consumption ◽  
Resistance Exercise Training ◽  
Over The Counter ◽  
Cox 1

Evidence suggests that consumption of over-the-counter cyclooxygenase (COX) inhibitors may interfere with the positive effects that resistance exercise training has on reversing sarcopenia in older adults. This study examined the influence of acetaminophen or ibuprofen consumption on muscle mass and strength during 12 wk of knee extensor progressive resistance exercise training in older adults. Thirty-six individuals were randomly assigned to one of three groups and consumed the COX-inhibiting drugs in double-blind placebo-controlled fashion: placebo (67 ± 2 yr; n = 12), acetaminophen (64 ± 1 yr; n = 11; 4 g/day), and ibuprofen (64 ± 1 yr; n = 13; 1.2 g/day). Compliance with the resistance training program (100%) and drug consumption (via digital video observation, 94%), and resistance training intensity were similar ( P > 0.05) for all three groups. Drug consumption unexpectedly increased muscle volume (acetaminophen: 109 ± 14 cm3, 12.5%; ibuprofen: 84 ± 10 cm3, 10.9%) and muscle strength (acetaminophen: 19 ± 2 kg; ibuprofen: 19 ± 2 kg) to a greater extent ( P < 0.05) than placebo (muscle volume: 69 ± 12 cm3, 8.6%; muscle strength: 15 ± 2 kg), when controlling for initial muscle size and strength. Follow-up analysis of muscle biopsies taken from the vastus lateralis before and after training showed muscle protein content, muscle water content, and myosin heavy chain distribution were not influenced ( P > 0.05) by drug consumption. Similarly, muscle content of the two known enzymes potentially targeted by the drugs, COX-1 and -2, was not influenced ( P > 0.05) by drug consumption, although resistance training did result in a drug-independent increase in COX-1 (32 ± 8%; P < 0.05). Drug consumption did not influence the size of the nonresistance-trained hamstring muscles ( P > 0.05). Over-the-counter doses of acetaminophen or ibuprofen, when consumed in combination with resistance training, do not inhibit and appear to enhance muscle hypertrophy and strength gains in older adults. The present findings coupled with previous short-term exercise studies provide convincing evidence that the COX pathway(s) are involved in the regulation of muscle protein turnover and muscle mass in humans.

scholarly journals Response of muscle protein turnover to insulin after acute exercise and training

1986 ◽  
Vol 240 (3) ◽  
pp. 651-657 ◽  
Author(s):  
T A Davis ◽  
I E Karl
Keyword(s):  
Protein Synthesis ◽  
Exercise Training ◽  
Protein Turnover ◽  
Acute Exercise ◽  
Muscle Protein ◽  
Muscle Protein Turnover ◽  
Exercise And Training ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

To determine whether the enhanced insulin-sensitivity of glucose metabolism in muscle after acute exercise also extends to protein metabolism, untrained and exercise-trained rats were subjected to an acute bout of exercise, and the responses of protein synthesis and degradation to insulin were measured in epitrochlearis muscles in vitro. Acute exercise of both untrained and trained rats decreased protein synthesis in muscle in the absence or presence of insulin, but protein degradation was not altered. Exercise training alone had no effect on protein synthesis or degradation in muscle in the absence or presence of insulin. Acute exercise or training alone enhanced the sensitivities of both protein synthesis and degradation to insulin, but the enhanced insulin-sensitivities from training alone were not additive to those after acute exercise. These results indicate that: a decrease in protein synthesis is the primary change in muscle protein turnover after acute exercise and is not altered by prior exercise training, and the enhanced insulin-sensitivities of metabolism of both glucose and protein after either acute exercise or training suggest post-binding receptor events.

scholarly journals Aerobic Exercise Training Increases Skeletal Muscle Protein Turnover in Healthy Adults at Rest

2006 ◽  
Vol 136 (2) ◽  
pp. 379-383 ◽  
Author(s):  
Matthew A. Pikosky ◽  
Patricia C. Gaine ◽  
William F. Martin ◽  
Kimberly C. Grabarz ◽  
Arny A. Ferrando ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Aerobic Exercise ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Healthy Adults ◽  
Aerobic Exercise Training ◽  
Skeletal Muscle Protein ◽  
Muscle Protein Turnover
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