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


METHODS
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.


CONCLUSIONS
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.
Verdijk
Lex B
LB
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
Jonkers
Richard A M
RA
Gleeson
Benjamin G
BG
Beelen
Milou
M
Meijer
Kenneth
K
Savelberg
Hans H C M
HH
Wodzig
Will K W H
WK
Dendale
Paul
P
van Loon
Luc J C
LJ
D015502:Absorptiometry, Photon; D000368:Aged; D000375:Aging / Q000502:physiology*; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism; D019587:Dietary Supplements; D006801:Humans; D006984:Hypertrophy; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D009133:Muscular Atrophy / Q000517:prevention & control; D009751:Nutritional Requirements; D009752:Nutritional Status; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014891:Weight Lifting / Q000502:physiology*
D004044:Dietary Proteins