Efficacy of a Regression Method to Confirm VO2max in Middle-Aged and Older Adults: A Pilot Study

Verification testing following a maximal graded exercise test (GXT) has been shown to be effective at indicating whether VO2max was attained for middle-aged and older adults but performing two maximal efforts in a single day may not be practical or possible for certain individuals. PURPOSE: To evaluate the efficacy of a regression method for identifying a VO2 plateau in order to confirm the attainment of VO2max. METHODS: Twenty-one recreationally active (VO2max: 21.8-50.3 ml/kg/min) middle-aged and older (46-76 yrs.) men (n=11) and women (n=10) completed an individualized ramp GXT on the cycle ergometer, and one hour later, a verification protocol at 105% of their maximal work rate (WR) achieved during the GXT. Verification criterion was met if the difference between the highest VO2 during the verification was ≤2% greater than the VO2max achieved during the GXT. VO2 plateau was identified by least-squares regression analysis of the 4 minutes immediately prior to the last 2 minutes of the VO2-WR curve. Modelled VO2max was extrapolated using the VO2-WR regression equation and the maximum WR achieved during the GXT. If the difference between modelled and actual VO2max was \u3e50% of the slope for the linear portion of the VO2-WR relationship relative to the assigned protocol, then a plateau was observed. McNemar’s test of marginal homogeneity was used to detect differences in the proportion of paired data of individuals’ attainment of VO2max criteria. RESULTS: Of the 21 participants,15 (71.4%) met the verification criterion while 6 (28.6%) did not, compared to the regression method where 16 (76.2%) achieved the regression criterion while 5 (23.8%) did not. McNemar’s test revealed no significant difference between participants’ ability to achieve the regression and verification criteria (Χ2(1)=0, p=.999). CONCLUSION: The regression method used in this study may be an effective strategy for determining VO2 plateau and confirming that VO2max was attained during a GXT with middle-aged and older adults on a cycle ergometer. This time-efficient regression method is comparable with the verification criterion but does not require a second maximal test, which may be advantageous for those where the verification trial may not be practical