The Need for Reporting Metabolic Sampling Interval in Publication: An Example Using Maximal VO2 Values and Running Economy

Authors

Chase M. Harbach, Abilene Christian UniversityFollow
Matthew J. Garver, Abilene Christian UniversityFollow
Cory M. Scheadler, Northern Kentucky UniversityFollow
Sarah J. Taylor, Abilene Christian UniversityFollow
Logan M. Smith, Abilene Christian UniversityFollow
Taylor G. Flowers, Abilene Christian UniversityFollow
Heather X. Johnston, Abilene Christian UniversityFollow

Abstract

Background: Knowledge of metabolic outcomes, such as maximal oxygen consumption (VO₂) or running economy, has wide-ranging application. Metabolic outcomes are widely reported in literature yet the metabolic sampling interval (example: breath-by-breath, 30-sec average) utilized for collection is rarely ever stated. Purpose: The purposes of the present investigation were to probe the potential discrepancies created when analyzing running economy and VO_2max raw metabolic data with four different metabolic sampling intervals. Methods: Five recreationally-active and endurance-trained subjects were included in the present analysis and four metabolic sampling intervals were analyzed: 30-sec average, 20-sec average, 8-breath, and 4-breath. Subjects engaged in 4-min running economy phases at 55 and 65% of their VO_2max before entering into a maximal protocol purposed to elicit VO_2max in 8-12 minutes. Utilizing the steady state and maximal VO₂ data, metabolic sampling intervals were analyzed for their effect on reported VO₂ values. Results: For running economy at 55%, there was no differences found (f = 0.207; df = 1.862; p = 0.799) between sampling frequencies when analyzed by repeated measures analysis of variance and corrected with Greenhouse-Geisser for a violation of sphericity. For running economy at 65%, there were also no differences ­found (f = 1.456; df = 3; p = 0.799) between sampling frequencies. For inspection, the relative VO₂ values were: 27.2 (±3.1), 27.9 (±4.1), 28.4 (±3.6), and 28.8 (±5.1) for the 30-sec, 20-sec, 8-breath, and 4-breath average, respectively. Maximal VO₂ values of 53.0 (±6.6), 55.1 (±7.2), 55.1 (±7.2), and 59.6 (±9.4) for the 30-sec, 20-sec, 8-breath, and 4-breath average, respectively, were found to be significantly different (f = 21.062; df = 1.278; p < 0.001) after adjusting for a violation of sphericity (p < 0.001). Bonferroni analysis indicated differences between the 30-sec average and all other averages and also the 20-sec and 8-breath averages when compared against the 4-breath average. The 4-breath average yielded the highest VO_2max value. Coincidentally, the 20-sec and 8-breath averages were identical. Conclusion: In the present investigation of raw metabolic data, sampling interval was found to impact the maximal oxygen consumption (VO_2max) values but not running economy values when investigating a small sample of data with four select sampling intervals. The report of maximal VO₂ is rather common in the literature and knowing sample interval is vital for between-study comparison, determination of regression-related activities, or for pre-post comparison of data from the same or different labs.

Recommended Citation

Harbach, Chase M.; Garver, Matthew J.; Scheadler, Cory M.; Taylor, Sarah J.; Smith, Logan M.; Flowers, Taylor G.; and Johnston, Heather X. (2015) "The Need for Reporting Metabolic Sampling Interval in Publication: An Example Using Maximal VO2 Values and Running Economy," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 7, Article 27.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss7/27