Kinugasa Ryuta, Akima Hiroshi, Ota Akemi, Ohta Atsutane, Sugiura Katsumi, Kuno Shin-Ya
Graduate School of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukasawa, Setagaya, 158-8508, Tokyo, Japan.
Eur J Appl Physiol. 2004 Mar;91(2-3):230-7. doi: 10.1007/s00421-003-0970-8. Epub 2003 Oct 22.
The purpose of this study was to examine the influence of short-term creatine (Cr) supplementation on exercise-induced transverse relaxation time (T2) and sprint performance during maximum intermittent cycling exercise using the muscle functional magnetic resonance imaging (mfMRI) technique. Twelve men were divided into a Cr supplementation group [the Cr group, taking 4 x (5 g Cr monohydrate + 2.5 g maltodextrin)/day], or a placebo supplementation group (the P group, taking 4 x 7.5 g maltodextrin/day). The allocation to the groups was based on cycling tests and the subject's physical characteristics, and thus was not randomized. A double-blind research design was employed for a 5-day supplementation period. mfMR images of the right thigh were collected at rest and immediately after two, five, and ten 6-s sprint bouts of maximum intermittent cycling exercise with a 30-s recovery interval between sets. Before and after supplementation, blood was taken to calculate lactate accumulation, and the muscle volume of the thigh was determined by MRI. Following supplementation, there was significant body mass gain in the Cr group ( P<0.05), whereas the P group did not change. The exercise-induced T2, blood lactate levels and sprint performance were not affected by Cr supplementation in any sprint bouts. These results suggest that short-term Cr supplementation does not influence short duration repetitive sprint performance and muscle activation and/or metabolic state during sprint cycling evaluated by mfMRI of the skeletal muscle in humans.
本研究的目的是使用肌肉功能磁共振成像（mfMRI）技术，研究短期补充肌酸（Cr）对最大间歇循环运动期间运动诱导的横向弛豫时间（T2）和短跑成绩的影响。12名男性被分为肌酸补充组[Cr组，每天服用4×（5 g一水肌酸+2.5 g麦芽糊精）]或安慰剂补充组（P组，每天服用4×7.5 g麦芽糊精）。分组是基于自行车测试和受试者的身体特征，因此不是随机分组。采用双盲研究设计进行为期5天的补充期。在休息时以及在进行两组之间有30秒恢复间隔的两次、五次和十次6秒最大间歇循环运动冲刺回合后立即采集右大腿的mfMR图像。在补充前后采集血液以计算乳酸积累，并通过MRI测定大腿的肌肉体积。补充后，Cr组体重显著增加（P<0.05），而P组没有变化。在任何冲刺回合中补充Cr均未影响运动诱导的T2、血乳酸水平和短跑成绩。这些结果表明短期补充Cr不会影响人类骨骼肌mfMRI评估下的短跑循环期间短时间重复短跑成绩以及肌肉激活和/或代谢状态。
