Utility Of Verification Test For Determination Of Vo2max In Recreationally Active Females

PURPOSE: A constant-load exercise bout to exhaustion (verification test) after a graded exercise test (GXT) is a valid method for confirmation of true maximal oxygen uptake (VO2max). However, females have been underrepresented in prior research on this topic. The purpose of this study was to assess the utility of a verification test to elicit VO2max in recreationally active females. METHODS: 18 females (mean ± SD age: 30 ± 7 years, BMI: 22.1 ± 1.9 kg) performed an incremental ramp GXT on a cycle ergometer, followed by 10-min of active recovery, followed by a constant-load verification test (100% maximal workload achieved during GXT) until volitional fatigue. VO2 and heart rate (HR) were continuously measured using indirect calorimetry and Polar HR monitor, respectively. For the ramp and verification tests, the mean of the two highest consecutive 15-sec VO2 averages was taken as VO2max. The highest recorded HR was taken as the HR maximum (HRmax) on the ramp and verification tests. Repeated measures ANOVA was used to assess differences in VO2max and HRmax between tests within-subject. Pearson’s correlations were used to assess relationships between time on each test and differences in VO2max and HRmax. RESULTS: VO2max did not differ between ramp (2.15 ± 0.45 L/min) and verification (2.13 ± 0.35 L/min) tests (p = 0.64). Similarly, HRmax did not differ between ramp (177 ± 9 bpm) and verification (178 ± 10 bpm) tests (p = 0.54). However, 8 participants (44%) achieved a VO2max that was ≥2% (range: +2.0 to 10.2%; 0.04 to 0.16 L/min) higher than during the ramp test, and 10 participants (56%) achieved a higher HRmax during the verification test (range: +2 to 10 bpm). Furthermore, the highest VO2max (2.20 ± 0.42 L/min) and HRmax (180 ± 10 bpm) achieved on either test (ramp or verification) was significantly higher than the VO2max (2.15 ± 0.45 L/min, p = 0.004) and HRmax (177 ± 9 bpm, p = 0.004) achieved on the ramp test alone. Finally, differences in both VO2max and HRmax between the 2 tests (verification-ramp) were inversely correlated with the duration of the ramp test (r = -0.75, p < 0.001 and r = -0.56, p = 0.02, respectively). CONCLUSIONS: A verification test may be a useful tool for determining the highest VO2max and HRmax during cycle ergometry in recreationally active females, particularly in individuals with shorter ramp tests. Supported by: Texas Woman's University ORSP Small Grant