Kendall Kristina L, Smith Abbie E, Graef Jennifer L, Fukuda David H, Moon Jordan R, Beck Travis W, Cramer Joel T, Stout Jeffrey R
Metabolic and Body Composition Laboratory, Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, Norman, Oklahoma 73019, USA.
J Strength Cond Res. 2009 Sep;23(6):1663-9. doi: 10.1519/JSC.0b013e3181b1fd1f.
The critical power test provides 2 measures, critical power (CP) and anaerobic working capacity (AWC). In theory, the CP measurement represents the maximal power output that can be maintained without fatigue, and AWC is an estimate of work capacity associated with muscle energy reserves. High-intensity interval training (HIIT) has been shown to be an effective training method for improving endurance performance, including VO2PEAK. In addition, creatine (Cr) supplementation has been reported to improve AWC without training; however, it has shown no effect on CP. The purpose of this study was to examine the effects of 4 weeks of HIIT with Cr supplementation on CP and AWC. Forty-two recreationally active men volunteered to participate in this study. Participants were randomly assigned to 1 of 3 groups: Cr (n = 16), 10 g Cr + 10 g dextrose; placebo (PL, n = 16), 20 g dextrose; control (CON, n = 10), no treatment. Before and after supplementation, each participant performed a maximal oxygen consumption test VO2PEAK on a cycle ergometer to establish peak power output (PPO). Participants then completed a CP test involving 3 exercise bouts with the workloads set as a percentage of their PPO to determine CP and AWC. After a 2-week familiarization period of training and supplementing, PPO, CP, and AWC were remeasured before an additional 4 weeks of HIIT and supplementation were completed. Training consisted of 5 sets of 2-minute exercise bouts with 1 minute rest in between performed on the cycle ergometer, with intensities based on PPO. A significant improvement in CP was observed in the Cr group (6.72% +/- 2.54%), whereas PL showed no significant change (3.87% +/- 2.30%), and CON significantly decreased (6.27% +/- 2.38%). Furthermore, no changes in AWC were observed in any of the groups after treatment. The current findings suggest that Cr supplementation may enhance the effects of intense interval endurance training on endurance performance changes.
临界功率测试提供了两项指标，即临界功率（CP）和无氧工作能力（AWC）。理论上，CP测量值代表了在无疲劳状态下可维持的最大功率输出，而AWC是与肌肉能量储备相关的工作能力的一种估计。高强度间歇训练（HIIT）已被证明是一种提高耐力表现（包括最大摄氧量峰值）的有效训练方法。此外，据报道补充肌酸（Cr）无需训练就能提高AWC；然而，它对CP没有影响。本研究的目的是探讨为期4周的补充Cr的HIIT对CP和AWC的影响。42名有休闲运动习惯的男性自愿参与本研究。参与者被随机分配到3组中的1组：Cr组（n = 16），10克Cr + 10克葡萄糖；安慰剂组（PL，n = 16），20克葡萄糖；对照组（CON，n = 10），不进行任何处理。在补充前后，每位参与者在功率自行车上进行一次最大摄氧量测试VO2PEAK，以确定峰值功率输出（PPO）。参与者随后完成一项CP测试，该测试包括3组运动，运动负荷设定为其PPO的一定百分比，以确定CP和AWC。在经过为期2周的训练和补充的熟悉期后，在完成另外4周的HIIT和补充之前，重新测量PPO、CP和AWC。训练包括在功率自行车上进行5组2分钟的运动，每组之间休息1分钟，强度基于PPO。在Cr组中观察到CP有显著改善（6.72% +/- 2.54%），而PL组无显著变化（3.87% +/- 2.30%），CON组显著下降（6.27% +/- 2.38%）。此外，治疗后任何一组的AWC均未观察到变化。目前的研究结果表明，补充Cr可能会增强高强度间歇耐力训练对耐力表现变化的影响。
