Whey protein before and during resistance exercise has no effect on muscle mass and strength in untrained young adults.
OBJECTIVE
To determine the effects of whey protein before and during resistance exercise (RE) on body composition and strength in young adults.


METHODS
Participants were randomized to ingest whey protein (PRO; 0.3 g/kg protein; n = 9, 24.58 ± 1.8 yr, 88.3 ± 17.1 kg, 172.5 ± 8.0 cm) or placebo (PLA; 0.2 g/kg cornstarch maltodextrin + 0.1 g/kg sucrose; n = 8, 23.6 ± 4.4 yr, 82.6 ± 16.1 kg, 169.4 ± 9.2 cm) during RE (3 sets of 6-10 repetitions for 9 whole-body exercises), which was performed 4 d/wk for 8 wk. PRO and PLA were mixed with water (600 ml); 50% of the solution containing 0.15 g/kg of PRO or PLA was consumed immediately before the start of exercise, and ~1.9% of the remaining solution containing ~0.006 g/kg of PRO or PLA was consumed immediately after each training set. Before and after the study, measures were taken for lean-tissue mass (dual-energy X-ray absorptiometry), muscle size of the elbow and knee flexors and extensors and ankle dorsiflexors and plantar flexors (ultrasound), and muscle strength (1-repetition-maximum chest press).


RESULTS
There was a significant increase (p < .05) in muscle size of the knee extensors (PRO 0.6 ± 0.4 cm, PLA 0.1 ± 0.5 cm), knee flexors (PRO 0.4 ± 0.6 cm, PLA 0.5 ± 0.7 cm) and ankle plantar flexors (PRO 0.6 ± 0.7 cm, PLA 0.8 ± 1.4 cm) and chest-press strength (PRO 16.6 ± 11.1 kg, PLA 9.1 ± 14.6 kg) over time, with no differences between groups.


CONCLUSIONS
The ingestion of whey protein immediately before the start of exercise and again after each training set has no effect on muscle mass and strength in untrained young adults.
Faculty of Kinesiology and Health Studies, University of Regina, Regina, SK, Canada.
Krissy D
KD
Weisgarber
Darren G
DG
Candow
Emelie S M
ES
Vogt
D015502:Absorptiometry, Photon; D000328:Adult; D001628:Beverages; D004032:Diet; D015930:Diet Records; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D024510:Muscle Development; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D055070:Resistance Training; D064133:Sports Nutritional Physiological Phenomena; D014463:Ultrasonography; D000067816:Whey Proteins / Q000008:administration & dosage* / Q000009:adverse effects; D055815:Young Adult
D000067816:Whey Proteins