Resistance training and timed essential amino acids protect against the loss of muscle mass and strength during 28 days of bed rest and energy deficit

• Published in: Journal of applied physiology (1985) Vol. 105; no. 1; pp. 241 - 248
• Main Authors: Brooks, Naomi, Cloutier, Gregory J, Cadena, Samuel M, Layne, Jennifer E, Nelsen, Carol A, Freed, Alicia M, Roubenoff, Ronenn, Castaneda-Sceppa, Carmen
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.07.2008; American Physiological Society
• Subjects: Absorptiometry, Photon; Adult; Amino acids; Amino Acids, Essential - pharmacology; Biological and medical sciences; Body Composition - drug effects; Body Composition - physiology; Energy Intake - physiology; Energy Metabolism - drug effects; Energy Metabolism - physiology; Exercise; Fundamental and applied biological sciences. Psychology; Humans; Insulin; Insulin - blood; Male; Middle Aged; Muscle Strength - drug effects; Muscle, Skeletal - drug effects; Muscle, Skeletal - physiology; Muscular system; Organ Size - drug effects; Physical Fitness - physiology; Rest - physiology; Tomography, X-Ray Computed; Weight Lifting - physiology; Physical exercise; Physical training; Muscle strength; resistance exercise training; Space flight; Bed rest; Body composition; spaceflight; Vertebrata; Mammalia; amino acid supplementation; Aminoacid; Supplementation; Muscle mass
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01346.2007

1 Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University; 2 Bouve College of Health Sciences, Northeastern University; and 3 Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts Submitted 18 December 2007 ; accepted in final form 13 May 2008 Spaceflight and bed rest (BR) result in losses of muscle mass and strength. Resistance training (RT) and amino acid (AA) supplementation are potential countermeasures to minimize these losses. However, it is unknown if timing of supplementation with exercise can optimize benefits, particularly with energy deficit. We examined the effect of these countermeasures on body composition, strength, and insulin levels in 31 men (ages 31–55 yr) during BR (28 days) followed by active recovery (14 days). Subjects were randomly assigned to essential AA supplementation (AA group, n = 7); RT with AA given 3 h after training (RT group, n = 12); or RT with AA given 5 min before training (AART group, n = 12). Energy intake was reduced by 8 ± 6%. Midthigh muscle area declined with BR for the AA > RT > AART groups: –11%, –3%, –4% ( P = 0.05). Similarly, greatest losses in lower body muscle strength were seen in the AA group (–22%). These were attenuated in the exercising groups [RT (–8%) and AART (–6%; P < 0.05)]. Fat mass and midthigh intramuscular fat increased after BR in the AA group (+3% and +14%, respectively), and decreased in the RT (–5% and –4%) and AART groups (–1 and –5%; P = 0.05). Muscle mass and strength returned toward baseline after recovery, but the AA group showed the lowest regains. Combined resistance training with AA supplementation pre- or postexercise attenuated the losses in muscle mass and strength by approximately two-thirds compared with AA supplement alone during BR and energy deficit. These data support the efficacy of combined AA and RT as a countermeasure against muscle wasting due to low gravity. resistance exercise training; muscle strength; body composition; spaceflight; amino acid supplementation Address for reprint requests and other correspondence: C. Castaneda-Sceppa, Bouve College of Health Sciences, Northeastern Univ., 316E Robinson Hall, Boston, MA 02115