Pronounced energy restriction with elevated protein intake results in no change in proteolysis and reductions in skeletal muscle protein synthesis that are mitigated by resistance exercise

2017 ◽  
Vol 32 (1) ◽  
pp. 265-275 ◽  
Author(s):  
Amy J. Hector ◽  
Chris McGlory ◽  
Felipe Damas ◽  
Nicole Mazara ◽  
Steven K. Baker ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Energy Restriction ◽  
Skeletal Muscle Protein ◽  
Skeletal Muscle Protein Synthesis ◽  
Elevated Protein

scholarly journals Resistance exercise maintains skeletal muscle protein synthesis during bed rest

1997 ◽  
Vol 82 (3) ◽  
pp. 807-810 ◽  
Author(s):  
Arny A. Ferrando ◽  
Kevin D. Tipton ◽  
Marcas M. Bamman ◽  
Robert R. Wolfe
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Lean Body Mass ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Bed Rest ◽  
Skeletal Muscle Protein ◽  
Skeletal Muscle Protein Synthesis

Ferrando, Arny A., Kevin D. Tipton, Marcas M. Bamman, and Robert R. Wolfe. Resistance exercise maintains skeletal muscle protein synthesis during bed rest. J. Appl. Physiol. 82(3): 807–810, 1997.—Spaceflight results in a loss of lean body mass and muscular strength. A ground-based model for microgravity, bed rest, results in a loss of lean body mass due to a decrease in muscle protein synthesis (MPS). Resistance training is suggested as a proposed countermeasure for spaceflight-induced atrophy because it is known to increase both MPS and skeletal muscle strength. We therefore hypothesized that scheduled resistance training throughout bed rest would ameliorate the decrease in MPS. Two groups of healthy volunteers were studied during 14 days of simulated microgravity. One group adhered to strict bed rest (BR; n = 5), whereas a second group engaged in leg resistance exercise every other day throughout bed rest (BREx; n = 6). MPS was determined directly by the incorporation of infusedl-[ ring-13C6]phenylalanine into vastus lateralis protein. After 14 days of bed rest, MPS in the BREx group did not change and was significantly greater than in the BR group. Thus moderate-resistance exercise can counteract the decrease in MPS during bed rest.

scholarly journals Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise

2005 ◽  
Vol 289 (4) ◽  
pp. E678-E683 ◽  
Author(s):  
Douglas R. Bolster ◽  
Matthew A. Pikosky ◽  
P. Courtney Gaine ◽  
William Martin ◽  
Robert R. Wolfe ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Endurance Exercise ◽  
Dietary Protein ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Dietary Protein Intake ◽  
Skeletal Muscle Protein ◽  
Skeletal Muscle Protein Synthesis

This investigation evaluated the physiological impact of different dietary protein intakes on skeletal muscle protein synthesis postexercise in endurance runners. Five endurance-trained, male runners participated in a randomized, crossover design diet intervention, where they consumed either a low (0.8 g/kg; LP)-, moderate (1.8 g/kg; MP)-, or high (3.6 g/kg; HP)-protein diet for 4 wk. Diets were designed to be eucaloric with carbohydrate, fat, and protein approximating 60, 30, and 10%; 55, 30, and 15%; and 40, 30, and 30% for LP, MP, and HP, respectively. Substrate oxidation was assessed via indirect calorimetry at 3 wk of the dietary interventions. Mixed-muscle protein fractional synthetic rate (FSR) was measured after an endurance run (75 min at 70% V̇o2 peak) using a primed, continuous infusion of [2H5]phenylalanine. Protein oxidation increased with increasing protein intake, with each trial being significantly different from the other ( P < 0.01). FSR after exercise was significantly greater for LP (0.083%/h) and MP (0.078%/h) than for HP (0.052%/h; P < 0.05). There was no difference in FSR between LP and MP. This is the first investigation to establish that habitual dietary protein intake in humans modulates skeletal muscle protein synthesis after an endurance exercise bout. Future studies directed at mechanisms by which level of protein intake influences skeletal muscle turnover are needed.

Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit

2014 ◽  
Vol 306 (8) ◽  
pp. E989-E997 ◽  
Author(s):  
José L. Areta ◽  
Louise M. Burke ◽  
Donny M. Camera ◽  
Daniel W. D. West ◽  
Siobhan Crawshay ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Energy Deficit ◽  
Skeletal Muscle Protein ◽  
Short Term ◽  
Skeletal Muscle Protein Synthesis ◽  
Protein Ingestion

The myofibrillar protein synthesis (MPS) response to resistance exercise (REX) and protein ingestion during energy deficit (ED) is unknown. In young men ( n = 8) and women ( n = 7), we determined protein signaling and resting postabsorptive MPS during energy balance [EB; 45 kcal·kg fat-free mass (FFM)−1·day−1] and after 5 days of ED (30 kcal·kg FFM−1·day−1) as well as MPS while in ED after acute REX in the fasted state and with the ingestion of whey protein (15 and 30 g). Postabsorptive rates of MPS were 27% lower in ED than EB ( P < 0.001), but REX stimulated MPS to rates equal to EB. Ingestion of 15 and 30 g of protein after REX in ED increased MPS ∼16 and ∼34% above resting EB ( P < 0.02). p70 S6K Thr389 phosphorylation increased above EB only with combined exercise and protein intake (∼2–7 fold, P < 0.05). In conclusion, short-term ED reduces postabsorptive MPS; however, a bout of REX in ED restores MPS to values observed at rest in EB. The ingestion of protein after REX further increases MPS above resting EB in a dose-dependent manner. We conclude that combining REX with increased protein availability after exercise enhances rates of skeletal muscle protein synthesis during short-term ED and could in the long term preserve muscle mass.

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