Verification Testing to Confirm VO2max in Altitude-Residing, Endurance-Trained Runners.

We sought to explore the utility of the verification trial to confirm individual attainment of 'true' VO2max in altitude-residing, endurance-trained runners during treadmill exercise. 24 elite endurance-trained men and women runners (age=21.5±3.3 yr, ht=174.8±9.3 cm, body mass=60.5±6.7 kg, PR 800 m 127.5±13.1 s) completed a graded exercise test (GXT) trial (VO2max=60.0±5.8 mL·kg(-1)·min(-1)), and returned 20 min after incremental exercise to complete a verification trial (VO2max=59.6±5.7 mL·kg(-1)·min(-1)) of constant load, supramaximal exercise. The incidence of 'true' VO2max confirmation using the verification trial was 24/24 (100%) with all participants revealing differences in VO2max≤3% (the technical error of our equipment) between the GXT and verification trials. These findings support use of the verification trial to confirm VO2max attainment in altitude-residing, endurance-trained runners.

Comparison of intensities and rest periods for VO2max verification testing procedures.

We sought to determine the incidence of 'true' VO2max confirmation with the verification procedure across different protocols. 12 active participants (men n=6, women n=6) performed in random order 4 different maximal graded exercises tests (GXT) and verification bout protocols on 4 separate days. Conditions for the rest period and verification bout intensity were: A - 105% intensity, 20 min rest; B - 105% intensity, 60 min rest; C - 115% intensity, 20 min rest; D - 115% intensity, 60 min rest. VO2max confirmation (difference between peak VO2 GXT and verification trial<±3%) using the verification trial was 12/12 (100%), 12/12 (100%), 8/12 (66.70%), and 7/12 (58.33%) for protocols A, B, C, and D. There was a significant (p<0.05) effect of verification intensity on VO2max confirmation across all exercise test conditions (intensity effect within recovery 20 min (χ(2) (1)=4.800, p<0.05), intensity effect within recovery 60 min (χ(2) (1)=6.316, p<0.05)). No significant effect was found for incidence of VO2max confirmation with different rest periods. We recommend the use of 105% of the maximal GXT workload and 20 min rest periods when using verification trials to confirm VO2max in normally active populations.

The incidence of V˙O2 plateau at V˙O2max in a cardiac-diseased population.

We sought to determine the incidence of V˙O(2) plateau at V˙O(2)max in a cardiovascular-diseased (CVD) population using 4 different sampling intervals (15-breath moving average, 15 s, 30 s, and 60 s) and 3 different V˙O(2) plateau criteria (≤50 mL · min(-1), ≤80 mL · min(-1), and ≤150 mL · min(-1)). A total of 69 people (62 ± 10 yrs.) with recently diagnosed CVD performed a maximal exercise test (10:07 ± 2:24 min) on a treadmill. The test was classified as maximal (n = 57, 2 430 ± 605 mL · min(-1)) if self-terminated due to fatigue or classified as symptom-limited (n = 12, 1 683 ± 438 mL · min(-1)) if symptoms presented. Chi-square analysis revealed a significant (p < 0.05) effect of sampling interval on incidence of V˙O(2) plateau at V˙O(2)max across all 3 V˙O(2) plateau criteria. The sampling interval had an increasingly stronger influence on the incidence of V˙O(2) plateau at V˙O(2)max with smaller criterion thresholds as evidenced by the Cramer's V statistics: [≤50 mL · min(-1) (Cramer's V = 0.548, p < 0.05], ≤80 mL · min(-1) [Cramer's V = 0.489, p < 0.05], ≤150 mL · min(-1) [Cramer's V = 0.214, p < 0.05]. Incidence of V˙O(2) plateau at V˙O(2)max in CVD individuals is significantly influenced by the sampling interval applied. Based on our findings we recommend a15 breath moving average and V˙O(2) plateau criterion of ≤50 mL · min(-1).