Hultman E, Sjöholm H
J Physiol. 1983 Dec;345:525-32. doi: 10.1113/jphysiol.1983.sp014994.
The quadriceps femoris muscles of nine volunteers were stimulated with intramuscular electrodes for 50 s. The stimulation frequency was 20 Hz and the voltage adjusted to produce an initial tension of 50-75% of the maximum voluntary contraction force. The force decreased after 25-30 s of contraction to reach a mean of 78% of the initial value after 50 s. During the stimulation up to four muscle biopsy samples were taken from each leg. The ATP turnover rate was initially 5.6 mmol kg-1 dry wt. s-1 and decreased during the later stages of contraction to 4.0 mmol kg-1 dry wt. s-1. The force declined at approximately the same rate as the ATP turnover during the contraction. The phosphocreatine (PCr) store decreased exponentially during contraction and was practically depleted at 50 s. Glycolysis began within 5 s after initiation of contraction. The rate of glycolysis measured as lactate accumulation increased with time throughout the entire contraction period.
用肌内电极对9名志愿者的股四头肌进行50秒的刺激。刺激频率为20赫兹，电压调整至产生最大自主收缩力50 - 75%的初始张力。收缩25 - 30秒后力量下降，50秒后平均降至初始值的78%。在刺激过程中，每条腿最多取4个肌肉活检样本。ATP周转率最初为5.6 mmol·kg-1干重·s-1，在收缩后期降至4.0 mmol·kg-1干重·s-1。收缩过程中力量下降的速率与ATP周转率大致相同。磷酸肌酸（PCr）储备在收缩过程中呈指数下降，50秒时几乎耗尽。糖酵解在收缩开始后5秒内开始。以乳酸积累量衡量的糖酵解速率在整个收缩期随时间增加。
