Nutritional Interventions to Stimulate Muscle Anabolism
903
breakdown. However, in the absence of food intake,
References
1. Welle S, Thornton C, Statt M. Myofibrillar protein synthesis in
net muscle protein balance will remain negative and,
young and old human subjects after three months of resistance
therefore, muscle hypertrophy can only occur when
training. Am J Physiol 1995; 268: E422-7
2. American College of Sports Medicine Position Stand. The rec-
ample food is ingested during post-exercise recov-
ommended quantity and quality of exercise for developing and
ery. The ingestion of carbohydrate following exer-
maintaining cardiorespiratory and muscular fitness, and flexi-
bility in healthy adults. Med Sci Sports Exerc 1998; 30: 975-91
cise has been shown to increase circulating insulin
3. Kraemer WJ, Fry AC. Strength testing: development and evalu-
concentrations, thereby reducing protein break-
ation of methodology. In: Maud PJ, Foster C, editors. Physio-
logical assessment of human fitness. Leeds: Human Kinetics,
down, without increasing muscle protein synthesis
1995: 115-33
rates. Ingestion of protein/amino acids is necessary
4. Koopman R, Manders RJ, Zorenc AH, et al. A single session of
to stimulate protein synthesis and, as such, to attain a
resistance exercise enhances insulin sensitivity for at least 24 h
in healthy men. Eur J Appl Physiol 2005; 94: 180-7
positive net protein balance. Administration of pro-
5. Koopman R, Manders RJ, Jonkers RA, et al. Intramyocellular
tein/amino acids (>15g) following resistance exer-
lipid and glycogen content are reduced following resistance
exercise in untrained healthy males. Eur J Appl Physiol 2006;
cise effectively increases muscle protein synthesis
96: 525-34
rates. Besides their role as the building blocks for
6. Rennie MJ, Tipton KD. Protein and amino acid metabolism
during and after exercise and the effects of nutrition. Annu Rev
de novo protein synthesis, amino acids, in particular
Nutr 2000; 20: 457-83
leucine, play a key regulatory role as signalling
7. Balagopal P, Rooyackers OE, Adey DB, et al. Effects of aging
on in vivo synthesis of skeletal muscle myosin heavy-chain
molecules modulating muscle protein metabolism.
and sarcoplasmic protein in humans. Am J Physiol 1997; 273:
However, information on the effects of nutrition and
E790-800
exercise on intracellular signalling through the
8. Nair KS, Halliday D, Griggs RC. Leucine incorporation into
mixed skeletal muscle protein in humans. Am J Physiol 1988;
mTOR and other, yet undefined, pathways in human
254: E208-13
skeletal muscle remains relatively scarce.
9. Volpi E, Ferrando AA, Yeckel CW, et al. Exogenous amino
acids stimulate net muscle protein synthesis in the elderly. J
The ingestion of protein following exercise is
Clin Invest 1998; 101: 2000-7
important for the athlete to maximise the muscle
10. Baar K, Esser K. Phosphorylation of p70(S6k) correlates with
increased skeletal muscle mass following resistance exercise.
adaptive response. However, the latter is also of
Am J Physiol 1999; 276: C120-7
important clinical relevance in the elderly. Aging is
11. Bodine SC, Stitt TN, Gonzalez M, et al. Akt/mTOR pathway is a
crucial regulator of skeletal muscle hypertrophy and can pre-
associated with a progressive decline in skeletal
vent muscle atrophy in vivo. Nat Cell Biol 2001; 3: 1014-9
muscle mass and function, contributing to the loss of
12. Reynolds TI, Bodine SC, Lawrence Jr JC. Control of Ser2448
phosphorylation in the mammalian target of rapamycin by
independence and the increased risk of developing
insulin and skeletal muscle load. J Biol Chem 2002; 277:
chronic metabolic diseases. Recent data imply that
17657-62
the anabolic effects of insulin are reduced in the
13. Phillips SM, Parise G, Roy BD, et al. Resistance-training-
induced adaptations in skeletal muscle protein turnover in the
elderly. However, the combined effects of exercise
fed state. Can J Physiol Pharmacol 2002; 80: 1045-53
and protein/amino acid administration can effective-
14. Ji G, Barsotti RJ, Feldman ME, et al. Stretch-induced calcium
release in smooth muscle. J Gen Physiol 2002; 119: 533-44
ly augment muscle protein synthesis in both the
15. MacKenna DA, Dolfi F, Vuori K, et al. Extracellular signal-
young and elderly. Whether additional leucine sup-
regulated kinase and c-Jun NH2-terminal kinase activation by
mechanical stretch is integrin-dependent and matrix-specific in
plementation can be used as an interventional strate-
rat cardiac fibroblasts. J Clin Invest 1998; 101: 301-10
gy to attenuate the loss of muscle mass in the elderly
16. Fryburg DA, Jahn LA, Hill SA, et al. Insulin and insulin-like
growth factor-I enhance human skeletal muscle protein anabo-
and/or cachectic patients remains to be established.
lism during hyperaminoacidemia by different mechanisms. J
Clin Invest 1995; 96: 1722-9
17. Goldspink G. Changes in muscle mass and phenotype and the
Acknowledgements
expression of autocrine and systemic growth factors by muscle
in response to stretch and overload. J Anat 1999; 194 (Pt 3):
323-34
No sources of funding were used to assist in the prepara-
18. Hameed M, Orrell RW, Cobbold M, et al. Expression of IGF-I
tion of this review. The authors have no conflicts of interest
splice variants in young and old human skeletal muscle after
that are directly relevant to the content of this review.
high resistance exercise. J Physiol 2003; 547: 247-54
©
2007 Adis Data Information BV. All rights reserved.
Sports Med 2007; 37 (10)