Hoffmann U, Essfeld D, Leyk D, Wunderlich H G, Stegemann J
Physiologisches Institut, Deutschen Sporthochschule Köln, Germany.
Eur J Appl Physiol Occup Physiol. 1994;69(2):93-7. doi: 10.1007/BF00609399.
Power-oxygen uptake (VO2) frequency responses can be used to predict VO2 responses to arbitrary exercise intensity patterns. It is still an open question for which range of exercise intensities such computed VO2 response patterns yield valid predictions. In the present study, we determined the power-VO2 frequency response of nine sports students by means of pseudo-randomised switching between 20 W and 80 W during upright and supine cycle exercise. Starting from a baseline of 20 W each subject also performed sustained step increases to 40 W, 80 W, 120 W, and 160 W in both positions. The individual VO2 step responses were then compared with the expected VO2 time-courses predicted on the basis of the individual VO2 frequency responses. The comparison showed a close agreement for the 20 W-40 W and 20 W-80 W steps in both positions. With larger step amplitudes the VO2 kinetics became increasingly slower than the predicted VO2 time course in both positions. During additional ramp tests (10 W.30 s-1) whole blood lactic acid concentration [la-]b tended to be higher in the supine position at exercise intensities higher than 160 W. The mean power at 4 mmol.l-1 [la-]b amounted to 234 (SD 32) W and 253 (SD 44) W (P < 5%) in the supine and the upright position, respectively. The maximal oxygen uptake relative to body mass was not found to be significantly different [upright, mean 57 (SD 10) ml.(min.kg)-1; supine, mean 54 (SD 10) ml.(min.kg)-1].(ABSTRACT TRUNCATED AT 250 WORDS)
功率-摄氧量（VO₂）频率响应可用于预测VO₂对任意运动强度模式的响应。对于何种运动强度范围，如此计算出的VO₂响应模式能产生有效的预测，这仍是一个悬而未决的问题。在本研究中，我们通过在直立和仰卧位自行车运动期间在20瓦和80瓦之间进行伪随机切换，测定了九名体育专业学生的功率-VO₂频率响应。从20瓦的基线开始，每个受试者在两个体位下还进行了持续的阶梯递增至40瓦、80瓦、120瓦和160瓦。然后将个体VO₂阶梯响应与基于个体VO₂频率响应预测的预期VO₂时间进程进行比较。比较显示，在两个体位下，20瓦至40瓦和20瓦至80瓦的阶梯中两者吻合度很高。随着阶梯幅度增大，在两个体位下VO₂动力学都变得比预测的VO₂时间进程越来越慢。在额外的递增负荷试验（10瓦·30秒⁻¹）中，在高于160瓦的运动强度下，仰卧位的全血乳酸浓度[la⁻]b往往更高。在仰卧位和直立位，[la⁻]b为4毫摩尔·升⁻¹时的平均功率分别为234（标准差32）瓦和253（标准差44）瓦（P<5%）。未发现相对于体重的最大摄氧量有显著差异[直立位，平均57（标准差10）毫升·（分钟·千克）⁻¹；仰卧位，平均54（标准差10）毫升·（分钟·千克）⁻¹]。（摘要截断于250字）
