Weisgarber Krissy D, Candow Darren G, Vogt Emelie S M
Faculty of Kinesiology and Health Studies, University of Regina, Regina, SK, Canada.
Int J Sport Nutr Exerc Metab. 2012 Dec;22(6):463-9. doi: 10.1123/ijsnem.22.6.463. Epub 2012 Jul 4.
To determine the effects of whey protein before and during resistance exercise (RE) on body composition and strength in young adults.
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).
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.
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.
确定在抗阻运动（RE）前及运动期间摄入乳清蛋白对年轻成年人身体成分和力量的影响。
参与者被随机分为两组，一组摄入乳清蛋白（PRO组；0.3克/千克蛋白质；n = 9，年龄24.58±1.8岁，体重88.3±17.1千克，身高172.5±8.0厘米），另一组摄入安慰剂（PLA组；0.2克/千克玉米淀粉麦芽糊精 + 0.1克/千克蔗糖；n = 8，年龄23.6±4.4岁，体重82.6±16.1千克，身高169.4±9.2厘米），在进行RE时（9项全身运动，每组6 - 10次重复，共3组），每周进行4天，持续8周。PRO和PLA均与水（600毫升）混合；在运动开始前立即饮用含0.15克/千克PRO或PLA溶液的50%，在每组训练后立即饮用剩余溶液中含约0.006克/千克PRO或PLA的约1.9%。在研究前后，采用双能X线吸收法测量瘦组织质量，用超声测量肘部和膝部屈伸肌以及踝背屈肌和跖屈肌的肌肉大小，并测量肌肉力量（1次最大重复卧推）。
随着时间推移，膝伸肌（PRO组增加0.6±0.4厘米，PLA组增加0.1±0.5厘米）、膝屈肌（PRO组增加0.4±0.6厘米，PLA组增加0.5±0.7厘米）、踝跖屈肌（PRO组增加0.6±0.7厘米，PLA组增加0.8±1.4厘米）的肌肉大小以及卧推力量（PRO组增加16.6±11.1千克，PLA组增加9.1±14.6千克）均有显著增加（p < 0.05），但两组之间无差异。
在运动开始前及每组训练后立即摄入乳清蛋白，对未经训练的年轻成年人的肌肉质量和力量没有影响。
