Wakayoshi K, Yoshida T, Udo M, Harada T, Moritani T, Mutoh Y, Miyashita M
Laboratory of Motor Behavioral Education, Faculty of Health and Sport Sciences, Osaka University, Japan.
Eur J Appl Physiol Occup Physiol. 1993;66(1):90-5. doi: 10.1007/BF00863406.
The purpose of this investigation was to determine whether the critical swimming velocity (vcrit), which is employed in competitive swimming, corresponds to the exercise intensity at maximal lactate steady state. vcrit is defined as the swimming velocity which could theoretically be maintained forever without exhaustion and expression as the slope of a regression line between swimming distances covered and the corresponding times. A total of eight swimmers were instructed to swim two different distances (200 m and 400 m) at maximal effort and the time taken to swim each distance was measured. In the present study, vcrit is calculated as the slope of the line connecting the two times required to swim 200 m and 400 m. vcrit determined by this new simple method was correlated significantly with swimming velocity at 4 mmol.l-1 of blood lactate concentration (r = 0.914, P < 0.01) and mean velocity in the 400 m freestyle (r = 0.977, P < 0.01). In the maximal lactate steady-state test, the subjects were instructed to swim 1600 m (4 x 400 m) freestyle at three constant velocities (98%, 100% and 102% of vcrit). At 100% vcrit blood lactate concentration showed a steady-state level of approximately 3.2 mmol.l-1 from the first to the third stage and at 98% of vcrit lactate concentration had a tendency to decrease significantly at the fourth stage. On the other hand, at 102% of vcrit, blood lactate concentration increased progressively and those of the third and fourth stages were significantly higher than those at 100% of vcrit (P < 0.05). These data suggest that vcrit, which can be calculated by performing two timed, maximal effort swimming tests, may correspond to the exercise intensity at maximal lactate steady state.
本研究的目的是确定竞技游泳中使用的临界游泳速度（vcrit）是否与最大乳酸稳态时的运动强度相对应。vcrit被定义为理论上可以永远保持而不会疲劳的游泳速度，并表示为所游距离与相应时间之间回归线的斜率。总共八名游泳运动员被要求尽全力游两个不同的距离（200米和400米），并测量游完每个距离所需的时间。在本研究中，vcrit计算为连接游200米和400米所需的两个时间的直线斜率。通过这种新的简单方法确定的vcrit与血乳酸浓度为4 mmol.l-1时的游泳速度显著相关（r = 0.914，P < 0.01），与400米自由泳的平均速度显著相关（r = 0.977，P < 0.01）。在最大乳酸稳态测试中，受试者被要求以三个恒定速度（vcrit的98%、100%和102%）游1600米（4×400米）自由泳。在100%vcrit时，血乳酸浓度从第一阶段到第三阶段显示出约3.2 mmol.l-1的稳态水平，在98%vcrit时，乳酸浓度在第四阶段有显著下降的趋势。另一方面，在102%vcrit时，血乳酸浓度逐渐增加，第三阶段和第四阶段的血乳酸浓度显著高于100%vcrit时的浓度（P < 0.05）。这些数据表明，通过进行两次定时、全力游泳测试计算出的vcrit可能与最大乳酸稳态时的运动强度相对应。
