Examining The Effect Different Averaging Methods Have On Interpretation Of Vo 2 Max Data

Abstract

VO2max is one of the most commonly used metrics in exercise physiology and related fields, and is typically measured through a graded exercise test. It is both the criterion measure of cardiorespiratory fitness and a predictor of endurance exercise performance. However, there is a lack of standardization in the reporting and measurement of VO2max. Differences in technology and measurement systems may affect results. Specifically, in a breath-by-breath measurement system, some form of data averaging or smoothing is used to calculate VO2max. We performed a brief examination of recent articles reporting VO2max data, and found that only 1 out of 20 articles stated the averaging methods used. PURPOSE: The purpose of this study was to compare four VO2max averaging methods, and to determine whether the method of averaging resulted in significantly different VO2max values. METHODS: VO2max data from a marathon training class at the University of Minnesota collected before and after training was analyzed. Participants were healthy college aged males and females (n = 55). The following averaging methods were compared: unaveraged, mid 5-of-7, 8-breath mean, and 30-second rolling average. Pairwise comparisons were done to test for differences between averaging methods. RESULTS: Pre-training means and standard deviations of VO2max (in ml.kg-1.min-1) for the respective data averaging techniques were as follows: Mid 5-of-7 (47.54 ± 7.66), 8-breath mean (46.95 ± 7.65), 30-second rolling (44.66 ± 7.31) and unaveraged (57.60 ± 10.71). Post-training VO2max values for the respective data averaging techniques were: Mid 5-of-7 (50.90 ± 8.15), 8-breath mean (50.40 ± 7.995), 30-second rolling (48.57 ± 7.993) and unaveraged (59.88 ± 10.74). There were statistically significant differences between all averaging methods tested (P < 0.05) in both pre- and post-training data. CONCLUSION: Studies reporting VO2max data should include the averaging method used in order to allow for interpretation and comparison between studies.