Impact of Data Averaging Strategies on V̇O 2max Assessment: Mathematical Modeling and Reliability

Scand J Med Sci Sports. 2019 Oct;29(10):1473-1488. doi: 10.1111/sms.13495. Epub 2019 Jul 18.

Abstract

Background: No consensus exists on how to average data to optimize V ˙ O2max assessment. Although the V ˙ O2max value is reduced with larger averaging blocks, no mathematical procedure is available to account for the effect of the length of the averaging block on V ˙ O2max. AIMS: To determine the effect that the number of breaths or seconds included in the averaging block has on the V ˙ O2max value and its reproducibility and to develop correction equations to standardize V ˙ O2max values obtained with different averaging strategies.

Methods: Eighty-four subjects performed duplicate incremental tests to exhaustion (IE) in the cycle ergometer and/or treadmill using two metabolic carts (Vyntus and Vmax N29). Rolling breath averages and fixed time averages were calculated from breath-by-breath data from 6 to 60 breaths or seconds.

Results: V ˙ O2max decayed from 6 to 60 breath averages by 10% in low fit ( V ˙ O2max < 40 mL kg-1 min-1 ) and 6.7% in trained subjects. The V ˙ O2max averaged from a similar number of breaths or seconds was highly concordant (CCC > 0.97). There was a linear-log relationship between the number of breaths or seconds in the averaging block and V ˙ O2max (R2 > 0.99, P < 0.001), and specific equations were developed to standardize V ˙ O2max values to a fixed number of breaths or seconds. Reproducibility was higher in trained than low-fit subjects and not influenced by the averaging strategy, exercise mode, maximal respiratory rate, or IE protocol.

Conclusions: The V ˙ O2max decreases following a linear-log function with the number of breaths or seconds included in the averaging block and can be corrected with specific equations as those developed here.

Keywords: aerobic performance; breath-by-breath; endurance training; maximal oxygen uptake; metabolic cart; reproducibility.

MeSH terms

  • Adolescent
  • Adult
  • Exercise Test*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Models, Theoretical
  • Oxygen Consumption*
  • Reproducibility of Results
  • Respiration
  • Young Adult