Branch J David
Department of Exercise Science, Physical Education, and Recreation at Old Dominion University, Norfolk, VA 23529-0196, USA.
Int J Sport Nutr Exerc Metab. 2003 Jun;13(2):198-226. doi: 10.1123/ijsnem.13.2.198.
Creatine supplementation (CS) has been reported to increase body mass and improve performance in high-intensity, short-duration exercise tasks. Research on CS, most of which has come into existence since 1994, has been the focus of several qualitative reviews, but only one meta-analysis, which was conducted with a limited number of studies.
This study compared the effects of CS on effect size (ES) for body composition (BC) variables (mass and lean body mass), duration and intensity (< or = 30 s, [ATP-PCr = A]; 30-150 s [glycolysis = G]; >150 s, [oxidative phosphorylation = O]) of the exercise task, type of exercise task (single, repetitive, laboratory, field, upper-body, lower-body), CS duration (loading, maintenance), and subject characteristics (gender, training status).
A search of MEDLINE and SPORTDiscus using the phrase "creatine supplementation" revealed 96 English-language, peer-reviewed papers (100 studies), which included randomized group formation, a placebo control, and human subjects who were blinded to treatments. ES was calculated for each body composition and performance variable.
Small, but significant (ES > 0, p < or = .05) ES were reported for BC (n=163, mean +/- SE=0.17 +/- 0.03), ATP-PCr (n=17, 0.24 +/- 0.02), G (n=135, 0.19 +/- 0.05), and O (n=69, 0.20 +/- 0.07). ES was greater for change in BC following a loading-only CS regimen (0.26 +/- 0.03, p=.0003) compared to a maintenance regimen (0.04 +/- 0.05), for repetitive-bout (0.25 +/- 0.03,p=.028) compared to single-bout (0.18 +/- 0.02) exercise, and for upper-body exercise (0.42 +/- 0.07, p<.0001) compared to lower (0.21 +/- 0.02) and total body (0.13 +/- 0.04) exercise. ES for laboratory-based tasks (e.g., isometric/isotonic/isokinetic exercise, 0.25 +/- 0.02) were greater (p=.014) than those observed for field-based tasks (e.g., running, swimming, 0.14 +/- 0.04). There were no differences in BC or performance ES between males and females or between trained and untrained subjects.
ES was greater for changes in lean body mass following short-term CS, repetitive-bout laboratory-based exercise tasks < or = 30 s (e.g., isometric, isokinetic, and isotonic resistance exercise), and upper-body exercise. CS does not appear to be effective in improving running and swimming performance. There is no evidence in the literature of an effect of gender or training status on ES following CS.
据报道，补充肌酸（CS）可增加体重，并提高高强度、短时间运动任务中的表现。自1994年以来出现了大量关于CS的研究，这些研究成为了多项定性综述的焦点，但仅有一项荟萃分析，且该分析所纳入的研究数量有限。
本研究比较了CS对身体成分（BC）变量（体重和去脂体重）的效应大小（ES）、运动任务的持续时间和强度（≤30秒，[磷酸原系统=A]；30 - 150秒[糖酵解系统=G]；>150秒，[氧化磷酸化系统=O]）、运动任务类型（单次、重复、实验室、现场、上肢、下肢）、CS持续时间（负荷期、维持期）以及受试者特征（性别、训练状态）的影响。
使用“补充肌酸”这一短语在MEDLINE和SPORTDiscus数据库中进行检索，共筛选出96篇英文、经同行评审的论文（100项研究），这些研究包括随机分组、安慰剂对照以及对治疗不知情的人类受试者。计算每个身体成分和表现变量的ES。
BC（n = 163，均值±标准误=0.17±0.03）、磷酸原系统（n = 17，0.24±0.02）、糖酵解系统（n = 135，0.19±0.05）和氧化磷酸化系统（n = 69，0.20±0.07）的ES虽小，但具有显著性（ES>0，p≤0.05）。与维持期方案（0.04±0.05）相比，仅进行负荷期CS方案后BC变化的ES更大（0.26±0.03，p = 0.0003）；与单次运动（0.18±0.02）相比，重复运动（0.25±0.03，p = 0.028）的ES更大；与下肢运动（0.21±0.02）和全身运动（0.13±0.04）相比，上肢运动（0.42±0.07，p<0.0001）的ES更大。基于实验室任务（如等长/等张/等速运动，0.25±0.02）的ES大于（p = 0.014）基于现场任务（如跑步、游泳，0.14±0.04）的ES。男性与女性之间或受过训练与未受过训练的受试者之间，BC或表现ES没有差异。
短期CS、≤30秒的重复式基于实验室的运动任务（如等长、等速和等张抗阻运动）以及上肢运动后，去脂体重变化的ES更大。CS似乎对提高跑步和游泳表现无效。文献中没有证据表明性别或训练状态对CS后的ES有影响。
