Performing a verification phase immediately after an incremental to maximal graded exercise test increases the proportion of participants who meet the job-related aerobic fitness standard for structural firefighters
Creators: name: Hancock, Ryan
name: Yavelberg, Loren
name: Gledhill, Norman
name: Jamnik, Veronica
Publisher: name: The Health & Fitness Journal of Canada
Year: 2022

description: Background: Maximal oxygen uptake (VO2max) is routinely measured in structural firefighter applicants to ensure that they possess the job-related aerobic fitness to carry out the essential physically-demanding and frequently-occurring on-the-job tasks in a safe and effective manner during emergency circumstances. Incremental to maximal graded exercise tests (GXT) are customarily used to measure VO2max via indirect calorimetry and typically depend on several secondary criteria to confirm a successful test. However, the use of these secondary criteria to verify VO2max has been criticized and the renewed interest in applying a verification phase (VP). This is particularly important for non-athletic individuals who may not possess the work tolerance required to push themselves to maximal effort during a continuous incremental to maximal GXT. Purpose: The purpose of this investigation was to i) determine what proportion of individuals are able to attain their true VO2max, as confirmed by the presence of a VO2 plateau during an incremental to maximal GXT and what proportion of individuals require a VP, ii) for those individuals who require a VP, to compare the VO2 values measured during the incremental to maximal GXT to those measured during the VP and iii) determine if a larger proportion of individuals are able to meet the aerobic fitness standard for firefighters when a VP is used following the incremental to maximal GXT. Importantly, differences in sex, age group and BMI were also examined. Methods: Participants completed an incremental to maximal GXT and a VP to measure their true VO2max, as confirmed by the presence of a VO2 plateau. Differences between the highest VO2values attained during the incremental to maximal GXT were compared to those attained during the VP using a paired t-test analysis (p &lt; 0.05). Considering sex, age and BMI, differences in the proportion of participants who were able to meet the aerobic fitness standard for firefighters between the GXT and were compared using a chi-square test for homogeneity (p &lt; 0.05). Results: 4,462 (4,179 male and 283 female) structural firefighter applicants completed an aerobic fitness test as part of a more comprehensive physical fitness assessment for structural firefighters. 1,096 (24.6%) participants were able to attain a “true” VO2max during the incremental to maximal GXT. While 3,366 (75.4%) participants were only able to attain a VO2peak during the incremental to maximal GXT and required the VP to attain a “true” VO2max. For these participants, the VO2peak values attained during the incremental to maximal GXT (47.0 + 6.1 mL·kg-1·min-1) were significantly lower than the “true” VO2max values attained during the VP (51.7 + 6.8 mL·kg-1·min-1), a significant mean difference of 4.7 mL·kg-1·min-1 (p &lt; 0.001). Similar differences were found to be significant in comparisons of sex, age group and BMI. In addition, the proportion of participants who met the job-related aerobic fitness standard for structural firefighters increased from 79.8% during the incremental to maximal GXT to 92.6% during the VP, a statistically significant difference of 12.8% (p &lt; 0.001). Differences were found to be significant independent of sex, age group or BMI group. Therefore, the VP added definitive value for 430 (12.8%) participants who were not able to meet the aerobic standard for structural firefighters during the incremental to maximal GXT but were able to meet the standard during the VP. Conclusions: These findings underscore the importance of a VP, immediately following an incremental to maximal GXT, to confirm the attainment of a “true” VO2max. This is particularly important for structural firefighter applicants whose VO2max values are used to determine if they meet the job-related aerobic fitness standards. Using a VP immediately after an incremental to maximal GXT to volitional fatigue, significantly increases the proportion of individuals who meet the job-related aerobic fitness standard for structural firefighters. These findings are particularly critical because they are independent of sex, age and BMI status. Funding: None received
description: The Health &amp; Fitness Journal of Canada, Vol. 14 No. 3 (2021): Proceedings from the 8th International Society for Physical Activity and Health Congress