Casey A, Constantin-Teodosiu D, Howell S, Hultman E, Greenhaff P L
Department of Physiology and Pharmacology, University of Nottingham Medical School, Queen's Medical Center, United Kingdom.
Am J Physiol. 1996 Jul;271(1 Pt 1):E38-43. doi: 10.1152/ajpendo.1996.271.1.E38.
Nine male subjects performed two bouts of 30-s maximal isokinetic cycling. Each bout of exercise was performed at 80 revolutions/min and was separated by 4 min of recovery. Mixed-muscle phosphocreatine (PCr) resynthesis during recovery (88.1 +/- 6.1%) was positively correlated with the restoration of total work production during bout 2 (r = 0.80, P < 0.05). During bout 1, ATP and PCr utilization were greater in type II compared with type I fibers (P < 0.01 and P < 0.05, respectively). The subsequent 4-min period of recovery was insufficient to allow total restoration of ATP and PCr in type II fibers, but restoration of ATP and PCr in type I fibers was almost complete. During the second bout of exercise, ATP and PCr utilization were reduced in type II fibers (P < 0.01), without a corresponding change in type I fibers, and performance was also significantly reduced. The reduction in work capacity observed during bout 2 may have been related to a slower resynthesis, and consequently a reduced availability, of ATP and PCr in type II fibers.
九名男性受试者进行了两轮30秒的最大等速骑行。每轮运动以每分钟80转进行，两轮之间有4分钟的恢复时间。恢复期间混合肌肉磷酸肌酸（PCr）的再合成（88.1±6.1%）与第二轮运动期间总功产生的恢复呈正相关（r = 0.80，P < 0.05）。在第一轮运动中，II型纤维的ATP和PCr利用率高于I型纤维（分别为P < 0.01和P < 0.05）。随后4分钟的恢复时间不足以使II型纤维的ATP和PCr完全恢复，但I型纤维的ATP和PCr恢复几乎完成。在第二轮运动中，II型纤维的ATP和PCr利用率降低（P < 0.01），而I型纤维没有相应变化，并且运动表现也显著降低。在第二轮运动中观察到的工作能力下降可能与II型纤维中ATP和PCr的再合成较慢有关，因此其可用性降低。
