The ability of a submaximal cycle ergometer test to detect longitudinal changes in VO2max

Background: The purpose of the present study was to examine the ability of a submaximal cycling test to detectlongitudinal changes in maximal oxygen uptake (VO2max) and examine the conformity between changes in meas‑ured and estimated VO2max over a time span of 5–8 years.Methods: A total of 35 participants (21 men and 14 women), aged 29 to 63 years, performed the Ekblom-Bak (EB)submaximal cycle test for estimation of VO2max and a maximal treadmill running test for direct measurement ofVO2max. The baseline tests were conducted between 2009 and 2012, and the follow-up tests were completed 5to 8 years later. Pearson’s coefcient of correlation (r) and paired sample t-test were used to analyse the associationbetween change in measured and estimated VO2max. Random and systematic errors between the measured andestimated VO2max were evaluated using Bland-Altman plots. Repeated measures ANOVA were used to test difer‑ences between changes over time.Results: There was no signifcant change in mean measured VO2max between baseline and follow-up (p = 0.91),however large individual variations were noted (− 0.78 to 0.61 L/min). The correlation between individual change inmeasured and estimated VO2max was r = 0.75 (p < 0.05), and the unstandardised B-coefcient from linear regressionmodelling was 0.88 (95% CI 0.61 to 1.15), i.e., for each litre of change in estimated VO2max, the measured value hadchanged 0.88 L. The correlation between baseline and follow-up errors (the diference between estimated-measuredVO2max at each occasion) was r = 0.84 (p < 0.05). With regard to the testing procedure, repeated measures ANOVArevealed that there was no signifcant diference between the group who exercised at the same work rates at baselineand follow-up (n = 25), and those who required a change in work rate (n = 10).Conclusions: The EB test detected a change in VO2max with reasonably good precision over a time span of 5–8years. Further studies are needed to evaluate if the test can be used in clinical populations and in subjects with difer‑ent medications