Greer F, Friars D, Graham T E
Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
J Appl Physiol (1985). 2000 Nov;89(5):1837-44. doi: 10.1152/jappl.2000.89.5.1837.
This two-part investigation compared the ergogenic and metabolic effects of theophylline and caffeine. Initially (part A), the ergogenic potential of theophylline on endurance exercise was investigated. Eight men cycled at 80% maximum O(2) consumption to exhaustion 90 min after ingesting either placebo (dextrose), caffeine (6 mg/kg; Caff), or theophylline (4.5 mg/kg Theolair; Theo). There was a significant increase in time to exhaustion in both the Caff (41.2+/-4.8 min) and Theo (37.4+/-5.0 min) trials compared with placebo (32.6+/-3.4 min) (P<0.05). In part B, the effects of Theo on muscle metabolism were investigated and compared with Caff. Seven men cycled for 45 min at 70% maximum O(2) consumption (identical treatment protocol as in part A). Neither methylxanthines (MX) affected muscle glycogen utilization (P>0.05). Only Caff increased plasma epinephrine (P<0.05), but both MX increased blood glycerol levels (P<0.05). Muscle cAMP was increased (P<0.05) by both MX at 15 min and remained elevated at 45 min with Theo. This demonstrates that both MX are ergogenic and that this can be independent of muscle glycogen.
这项分为两部分的研究比较了茶碱和咖啡因的促力作用及代谢效应。首先（A部分），研究了茶碱对耐力运动的促力潜能。八名男性在摄入安慰剂（葡萄糖）、咖啡因（6毫克/千克；Caff）或茶碱（4.5毫克/千克Theolair；Theo）90分钟后，以最大耗氧量的80%进行自行车运动直至力竭。与安慰剂组（32.6±3.4分钟）相比，Caff组（41.2±4.8分钟）和Theo组（37.4±5.0分钟）的力竭时间均显著延长（P<0.05）。在B部分，研究了Theo对肌肉代谢的影响，并与Caff进行比较。七名男性以最大耗氧量的70%进行45分钟的自行车运动（治疗方案与A部分相同）。两种甲基黄嘌呤（MX）均未影响肌肉糖原的利用（P>0.05）。只有Caff使血浆肾上腺素升高（P<0.05），但两种MX均使血液甘油水平升高（P<0.05）。两种MX在15分钟时均使肌肉环磷酸腺苷（cAMP）升高（P<0.05），且在45分钟时，Theo组仍保持升高。这表明两种MX均具有促力作用，且这种作用可能与肌肉糖原无关。
