Brannon T A, Adams G R, Conniff C L, Baldwin K M
Department of Physiology and Biophysics, University of California, Irvine 92717, USA.
Med Sci Sports Exerc. 1997 Apr;29(4):489-95. doi: 10.1097/00005768-199704000-00010.
Several reports have shown that the use of oral creatine (Cr) supplementation can increase performance during brief high intensity exercise in humans. The purpose of this study was to examine the separate and combined effects of Cr supplementation and high intensity run training on the performance capacity and biochemical properties of rodent skeletal muscle. Running performance was assessed following acute (10-d) and chronic (4-wk) Cr supplementation. Results indicate that Cr supplementation alone has ergogenic effects and the combination of run training plus Cr results in a more pronounced enhancement of performance than either intervention alone. The benefits of Cr supplementation were seen most clearly during repetitive bouts of high intensity interval running. Cr concentrations increased in both the slow soleus and fast plantaris muscles (P < 0.05) in response to Cr supplementation. Increased creatine concentrations appeared to be reflected in increased phosphorylated creatine (PCr). Citrate synthase (CS) activity was increased in both the soleus and plantaris muscles following training (P < 0.05). CS activity of the untrained soleus but not the plantaris responded to the dietary stimulus. There were no significant changes in either creatine phosphokinase activity or myosin heavy chain isoform distribution following training or supplementation. These results indicate that the gains in high intensity running performance seen following Cr loading are a combined result of increased aerobic (CS) and anaerobic (Cr and PCr) energy buffering capacity of the muscle.
多项报告显示，口服补充肌酸（Cr）可提高人类在短时间高强度运动中的表现。本研究的目的是检验补充Cr和高强度跑步训练对啮齿动物骨骼肌的运动能力和生化特性的单独及联合影响。在急性（10天）和慢性（4周）补充Cr后评估跑步表现。结果表明，单独补充Cr具有促力效应，跑步训练加Cr的联合干预比单独任何一种干预都能更显著地提高运动表现。在重复进行的高强度间歇跑步中，补充Cr的益处最为明显。补充Cr后，慢肌比目鱼肌和快肌跖肌中的Cr浓度均升高（P < 0.05）。肌酸浓度的增加似乎反映在磷酸肌酸（PCr）的增加上。训练后，比目鱼肌和跖肌中的柠檬酸合酶（CS）活性均增加（P < 0.05）。未训练的比目鱼肌而非跖肌的CS活性对饮食刺激有反应。训练或补充后，肌酸磷酸激酶活性或肌球蛋白重链同工型分布均无显著变化。这些结果表明，补充Cr后高强度跑步表现的提高是肌肉有氧（CS）和无氧（Cr和PCr）能量缓冲能力增加的综合结果。
