Importance of muscle phosphocreatine during intermittent maximal cycling.
Importance of muscle phosphocreatine during intermittent maximal cycling.
复制标题
间歇性最大循环期间肌肉磷酸肌酸的重要性。
DOI：
--
复制
发表时间：
1996
影响因子：
3.3
通讯作者：
L. Spriet
中科院分区：
文献类型：
--
作者：
M. Trump;G. Heigenhauser;C. T. Putman;L. Spriet
为了研究磷酸肌酸（PCr）降解在最大间歇性自行车运动中维持功率输出的重要性，7名健康男性完成了3次等速自行车运动（30 s，100转/min），两次运动之间休息4 min。在第2回合后，通过在休息期间套入大腿（袖带）阻断流向一条腿的血流，以防止PCr再合成，而另一条腿的循环完整（续）。然后移除袖带，完成约3次。在第3回合之前和之后立即从两条腿的股外侧肌取样肌肉活检。在第1回合（分别为9.3 +/- 0.5和9.6 +/- 0.5 kJ）和第2回合（分别为8.1 +/- 0.4和8.3 +/- kJ）期间，袖带和控制腿产生的总功相似。套囊防止了PCr的再合成，因为在套囊和对照腿中，前回合3的含量分别为20.7 +/- 8.4和63.0 +/- 3.3 mmol/kg干肌肉。在第3回合之前，套囊还导致乳酸盐、H+浓度（287 +/- 26 vs. 217 +/- 15 nM）、ADP、AMP和乙酰辅酶A的肌肉水平显著升高，但对其他糖酵解中间产物ATP或乙酰肉毒碱没有影响。第3回合的总功在袖带腿中显著减少15%（5.8 +/- 0.4 vs. 6.8 +/- 0.6 kJ）。在第3回合期间，袖带和对照腿的PCr降解分别为3.1和47.5 mmol/kg干肌肉，两条腿的乳酸盐蓄积量极低。在第3回合期间，腿间所有其他代谢物的变化无差异。结果表明，PCr贡献了约15%的总ATP供应在第三个30秒回合的最大等速循环和大部分的ATP提供在最初的15秒。在第三个30秒回合中，肌肉糖原分解对ATP供应的贡献最小（约10-15%），这表明有氧代谢在这种重复短跑模型中成为ATP的主要来源。
To examine the importance of phosphocreatine (PCr) degradation in maintaining power output during maximal intermittent cycling, seven healthy men completed three bouts of isokinetic cycling (30 s, 100 revolutions/min) with 4 min of rest between bouts. After bout 2, blood flow to one leg was occluded by cuffing the thigh (Cuff) during the rest period to prevent PCr resynthesis while the circulation to the other leg was intact (Cont). The cuff was then removed and bout 3 completed. Muscle biopsies were sampled from the vastus lateralis of both legs just before and immediately after bout 3. Total work produced by the Cuff and Cont legs was similar during bouts 1 (9.3 +/- 0.5 and 9.6 +/- 0.5 kJ, respectively) and 2 (8.1 +/- 0.4 and 8.3 +/- kJ, respectively). Cuffing prevented the resynthesis of PCr because pre-bout 3 contents were 20.7 +/- 8.4 and 63.0 +/- 3.3 mmol/kg dry muscle in the Cuff and Cont legs, respectively. Cuffing also resulted in significantly higher muscle levels of lactate, H+ concentration (287 +/- 26 vs. 217 +/- 15 nM), ADP, AMP, and acetyl-CoA before bout 3 but had no effect on other glycolytic intermediates, ATP, or acetylcarnitine. Total work in bout 3 was significantly reduced by 15% in the Cuff leg (5.8 +/- 0.4 vs. 6.8 +/- 0.6 kJ). PCr degradation during bout 3 was 3.1 and 47.5 mmol/kg dry muscle in the Cuff and Cont legs, respectively, and lactate accumulation was minimal in both legs. Changes in all other metabolites during bout 3 were not different between legs. The results suggest that PCr contributed approximately 15% of the total ATP provision during the third 30-s bout of maximal isokinetic cycling and that most of the ATP was provided during the initial 15 s. Muscle glycogenolysis contributed minimally to ATP provision (approximately 10-15%) during the third 30-s bout, suggesting that aerobic metabolism becomes the dominant source of ATP during this model of repeated sprinting.