Fig 1.
An illustration of how a variability in HR-VO2 relations at test and retest can affect measures of reproducibility.
Linear relations from regression equations, based on values from three submaximal work rates at test and retest, are illustrated as unbroken lines. Based on different HR and the regression equations, the estimated levels of VO2 can be higher, equal or lower at test compared to retest (see broken lines).
Table 1.
Characteristics of the participants, their commuting cycle rides and environments (mean ± SD).
Table 2.
Comparison of test protocols for determining VO2max and HRmax on a cycle ergometer (n = 14)(mean ± SD).
Table 3.
Test-retest of VO2 and HR at rest, submaximal and maximal cycle ergometer tests in the laboratory (mean ± SD and coefficient of variation, CV).
Table 4.
Positions of ergometer cycle work rates used to determine the HR-VO2 relations in males and females and responses to them in per cent of VO2max, heart rate reserve and per cent of HRmax, as well as RPE of legs and breathing during test 1 in the laboratory (mean ± SD).
Table 5.
The three HR levels from cycle commuting used to estimate VO2 based on the HR-VO2 regression equations at test and retest.
The corresponding levels of percent of heart rate reserve and percent of HRmax are also given (mean ± SD).
Fig 2.
Individual levels of differences and the 95% limits of agreement between estimations of VO2 (L · min-1) calculated from fixed levels of low, middle and high HR from commuter cycling as well as from repeated measurements of HR-VO2 relations based on three submaximal work rates (model 1).
The y-axes show absolute differences in VO2 against the mean values of the estimations from the repeated measurements on the x-axes.
Table 6.
Reproducibility of HR-VO2 regression equations and correlation coefficients based on three submaximal work rates (model 1)(means ± SD, n = 19).
Table 7.
The estimated levels of VO2 based on the regression equations in day 1 and 2 (model 1) and three levels of HR from cycle commuting (means ± SD, coefficients of variation (CV), and 95% confidence intervals (CI), n = 19).
Table 8.
Reproducibility of HR-VO2 regression equations and correlation coefficients based on three submaximal and a maximal work rate (model 2)(means ± SD, n = 19).
Table 9.
The estimated levels of VO2 based on the HR-VO2 regression equations in day 1 and 2 (model 2) and three levels of HR from cycle commuting (means ± SD, coefficients of variation (CV), and 95% confidence intervals (CI), n = 19).
Table 10.
Differences between model 1 and model 2 in the HR-VO2 regression equations and correlation coefficients (means ± SD, and 95% confidence intervals (CI), n = 19).
Table 11.
Differences between model 1 and model 2 in the estimated VO2 based on three levels of HR as well as in absolute and relative differences (means ± SD, and 95% confidence intervals (CI), n = 19).
Fig 3.
Individual levels of differences and the 95% limits of agreement between estimations of VO2 (L · min-1) calculated from fixed levels of low, middle and high HR from commuter cycling as well as from repeated measurements of HR-VO2 relations based on three submaximal work rates (model 2).
The y-axes show absolute differences in VO2 against the mean values of the estimations from the repeated measurements on the x-axes.