Vandenberghe K, Gillis N, Van Leemputte M, Van Hecke P, Vanstapel F, Hespel P
Faculty of Physical Education and Physiotherapy, Department of Kinesiology, Katholieke Universiteit Leuven, Belgium.
J Appl Physiol (1985). 1996 Feb;80(2):452-7. doi: 10.1152/jappl.1996.80.2.452.
This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.
本研究旨在比较口服肌酸（Cr）补充剂与肌酸补充剂联合咖啡因（Cr+C）对健康男性志愿者（n = 9）肌肉磷酸肌酸（PCr）水平及运动表现的影响。在服用安慰剂、Cr（0.5 g×kg-1×天-1）或Cr（0.5 g×kg-1×天-1）+C（5 mg×kg-1×天-1）6天前后，对腓肠肌进行31P核磁共振波谱分析，并在等速测力计上对膝伸肌进行最大间歇运动疲劳测试。运动包括连续三次最大等长收缩以及三个系列的90次、80次和50次最大自主收缩，各系列之间休息2分钟。在三种实验条件下，肌肉ATP浓度保持恒定。Cr和Cr+C使肌肉PCr浓度增加（P < 0.05）4 - 6%。然而，Cr使动态扭矩产生增加了10 - 23%（P < 0.05），而Cr+C未使其改变。在运动组间2分钟休息后即刻，Cr组的扭矩改善最为显著。数据表明，补充Cr可提高肌肉PCr浓度，并显著改善高强度间歇运动期间的运动表现。然而，这种促力作用会因摄入咖啡因而完全消除。
