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Am J Clin Nutr. 2009 Feb;89(2):608-16. doi: 10.3945/ajcn.2008.26626. Epub 2008 Dec 23.

Protein supplementation before and after exercise does not further augment skeletal muscle hypertrophy after resistance training in elderly men.

Author information

1
Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands. lex.verdijk@bw.unimaas.nl

Abstract

BACKGROUND:

Considerable discrepancy exists in the literature on the proposed benefits of protein supplementation on the adaptive response of skeletal muscle to resistance-type exercise training in the elderly.

OBJECTIVE:

The objective was to assess the benefits of timed protein supplementation on the increase in muscle mass and strength during prolonged resistance-type exercise training in healthy elderly men who habitually consume adequate amounts of dietary protein.

DESIGN:

Healthy elderly men (n = 26) aged 72 +/- 2 y were randomly assigned to a progressive, 12-wk resistance-type exercise training program with (protein group) or without (placebo group) protein provided before and immediately after each exercise session (3 sessions/wk, 20 g protein/session). One-repetition maximum (1RM) tests were performed regularly to ensure a progressive workload during the intervention. Muscle hypertrophy was assessed at the whole-body (dual-energy X-ray absorptiometry), limb (computed tomography), and muscle fiber (biopsy) level.

RESULTS:

The 1RM strength increased approximately 25-35% in both groups (P < 0.001). Dual-energy X-ray absorptiometry and computed tomography scans showed similar increases in leg muscle mass (6 +/- 1% in both groups; P < 0.001) and in the quadriceps (9 +/- 1% in both groups), from 75.9 +/- 3.7 and 73.8 +/- 3.2 to 82.4 +/- 3.9 and 80.0 +/- 3.0 cm2 in the placebo and protein groups, respectively (P < 0.001). Muscle fiber hypertrophy was greater in type II (placebo: 28 +/- 6%; protein: 29 +/- 4%) than in type I (placebo: 5 +/- 4%; protein: 13 +/- 6%) fibers, but the difference between groups was not significant.

CONCLUSION:

Timed protein supplementation immediately before and after exercise does not further augment the increase in skeletal muscle mass and strength after prolonged resistance-type exercise training in healthy elderly men who habitually consume adequate amounts of dietary protein. This trial was registered at clinicaltrials.gov as NCT00744094.

PMID:
19106243
DOI:
10.3945/ajcn.2008.26626
[Indexed for MEDLINE]

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