Edge Johann, Bishop David, Goodman Carmel
School of Human Movement and Exercise Science, The University of Western Australia, Perth, Australia.
J Appl Physiol (1985). 2006 Sep;101(3):918-25. doi: 10.1152/japplphysiol.01534.2005. Epub 2006 Apr 20.
This study determined the effects of altering the H(+) concentration during interval training, by ingesting NaHCO(3) (Alk-T) or a placebo (Pla-T), on changes in muscle buffer capacity (beta m), endurance performance, and muscle metabolites. Pre- and posttraining peak O(2) uptake (V(O2 peak)), lactate threshold (LT), and time to fatigue at 100% pretraining V(O2 peak) intensity were assessed in 16 recreationally active women. Subjects were matched on the LT, were randomly placed into the Alk-T (n = 8) or Pla-T (n = 8) groups, and performed 8 wk (3 days/wk) of six to twelve 2-min cycle intervals at 140-170% of their LT, ingesting NaHCO(3) or a placebo before each training session (work matched between groups). Both groups had improvements in beta m (19 vs. 9%; P < 0.05) and V(O2 peak) (22 vs. 17%; P < 0.05) after the training period, with no differences between groups. There was a significant correlation between pretraining beta m and percent change in beta m (r = -0.70, P < 0.05). There were greater improvements in both the LT (26 vs. 15%; P = 0.05) and time to fatigue (164 vs. 123%; P = 0.05) after Alk-T, compared with Pla-T. There were no changes to pre- or postexercise ATP, phosphocreatine, creatine, and intracellular lactate concentrations, or pH(i) after training. Our findings suggest that training intensity, rather than the accumulation of H(+) during training, may be more important to improvements in beta m. The group ingesting NaHCO(3) before each training session had larger improvements in the LT and endurance performance, possibly because of a reduced metabolic acidosis during training and a greater improvement in muscle oxidative capacity.
本研究通过摄入碳酸氢钠（碱训练组，Alk-T）或安慰剂（安慰剂训练组，Pla-T）来改变间歇训练期间的H⁺浓度，以确定其对肌肉缓冲能力（βm）变化、耐力表现和肌肉代谢产物的影响。对16名有休闲运动习惯的女性进行了训练前和训练后的峰值摄氧量（V̇O₂peak）、乳酸阈值（LT）以及在100%训练前V̇O₂peak强度下的疲劳时间评估。受试者根据LT进行匹配，随机分为碱训练组（n = 8）或安慰剂训练组（n = 8），并进行8周（每周3天）的六个至十二个2分钟的骑行间歇训练，强度为其LT的140 - 170%，每次训练前摄入碳酸氢钠或安慰剂（两组训练量匹配）。训练期后，两组的βm（分别提高19%和9%；P < 0.05）和V̇O₂peak（分别提高22%和17%；P < 0.05）均有所改善，组间无差异。训练前的βm与βm的变化百分比之间存在显著相关性（r = -0.70，P < 0.05）。与安慰剂训练组相比，碱训练组的LT（分别提高26%和15%；P = 0.05）和疲劳时间（分别提高164%和123%；P = 0.05）有更大改善。训练后，运动前和运动后的三磷酸腺苷（ATP）、磷酸肌酸、肌酸和细胞内乳酸浓度以及细胞内pH（pH(i)）均无变化。我们的研究结果表明，训练强度而非训练期间H⁺的积累，可能对βm的改善更为重要。每次训练前摄入碳酸氢钠的组在LT和耐力表现方面有更大改善，可能是因为训练期间代谢性酸中毒减轻以及肌肉氧化能力有更大提高。
