Tompuri T, et al. – The physicians conducted this work to determine reference for oxygen uptake (VO2)/workload (W)–slope among prepubertal children and define agreement between estimated and measured VO2PEAK. It was noted that reference values for VO2/W–slope among healthy prepubertal children were similar to those published for adults and among adolescents. Estimated and measured VO2PEAK should not be considered to be interchangeable because of the variation in the relationship between VO2 and W. In contrast, variation in the association between VO2 and W enables that VO2/W–slope can be applied as a diagnostic tool.