Horstman D H, Morgan W P, Cymerman A, Stokes J
Percept Mot Skills. 1979 Jun;48(3 Pt 2):1111-26. doi: 10.2466/pms.1979.48.3c.1111.
The purpose of this study was to describe the pattern of change in effort sense and the value of this pattern in predicting work end-point at relatively high work intensity (80% VO2 max). The patterns of change of various physiological functions were also observed. Two modes of work (walking and running) were compared to ascertain generalizability of results. 26 healthy male volunteers served as subjects. Time to exhaustion (ET) did not differ between walking and running. As work continued during both tasks, significant increases of VE, VE/VO2, VE/VCO2 and HR and a significant decrease of ETCO2 were observed; while VO2 and R remained fairly constant. VO2 and VE during the run were about 5% greater than during the walk; there were no differences in other measures. Ratings of perceived exertion (RPE) from the Borg Scale were identical for both conditions, increasing in a near linear fashion from a value of 12.9 at 25% of total work time to 18.9 at exhaustion. Ratings obtained at 25 and 50% ET were extrapolated to time of exhaustion; the point of intercept corresponded to ratings of perceived exertion for maximal work. At exhaustion, subjects rated perception of respiratory exertion for the walk as less than that for the run; perception of leg exertion was not different for the two conditions. Plasma lactate, epinephrine and norepinephrine concentrations following exercise did not differ between the two conditions. The findings for the walking experiment were essentially replicated in a second investigation involving another 28 subjects. It is concluded that, with the exception of VO2 and some ventilatory parameters, walking and running at the same relative work intensity resulted in comparable perceptual and physiological responses. Psychophysical judgments made early during work were reasonably accurate predictors of exhaustion time.
本研究的目的是描述在相对较高工作强度（80%最大摄氧量）下努力感的变化模式以及该模式在预测工作终点方面的价值。还观察了各种生理功能的变化模式。比较了两种工作模式（步行和跑步）以确定结果的普遍性。26名健康男性志愿者作为受试者。步行和跑步的力竭时间（ET）没有差异。在两项任务中随着工作的持续进行，观察到每分钟通气量（VE）、VE/VO₂、VE/VCO₂和心率（HR）显著增加，而呼气末二氧化碳分压（ETCO₂）显著降低；同时VO₂和呼吸交换率（R）保持相当稳定。跑步时的VO₂和VE比步行时大约高5%；其他测量指标没有差异。两种情况下Borg量表的主观用力感觉评分（RPE）相同，从总工作时间的25%时的12.9线性增加到力竭时的18.9。在25%和50%ET时获得的评分被外推到力竭时间；截距点对应于最大工作时的主观用力感觉评分。在力竭时，受试者对步行时呼吸用力的感觉评分低于跑步时；两种情况下腿部用力的感觉没有差异。运动后两种情况下的血浆乳酸、肾上腺素和去甲肾上腺素浓度没有差异。在另一项涉及另外28名受试者的研究中，步行实验的结果基本得到了重复。得出的结论是，除了VO₂和一些通气参数外，在相同相对工作强度下步行和跑步会导致相当的感知和生理反应。工作早期做出的心理物理学判断是力竭时间的合理准确预测指标。
