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Aging |
1 From the Department of Human Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, Netherlands (LBV, RAMJ, BGG, MB, KM, HHCMS, and LJCvL), and the Department of Clinical Chemistry, University Hospital Maastricht, Maastricht, Netherlands (WKWHW), Rehabilitation and Health Centre, Virga Jesse Hospital, Hasselt, Belgium (PD).
2 Supported in part by grants from the Anna Foundation, Leiden, Netherlands, and DSM Food Specialties, Delft, Netherlands. 3 Reprints not available. Address correspondence to LB Verdijk, Department of Human Movement Sciences, Faculty of Health, Medicine and Life Sciences, Maastricht University, PO Box 616, 6200 MD Maastricht, Netherlands. E-mail: lex.verdijk{at}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 
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.
Received for publication July 1, 2008. Accepted for publication November 21, 2008.
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J. J. Hulmi, J. Tannerstedt, H. Selanne, H. Kainulainen, V. Kovanen, and A. A. Mero Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men J Appl Physiol, May 1, 2009; 106(5): 1720 - 1729. [Abstract] [Full Text] [PDF]
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