Anaerobic capacity determined by maximal accumulated O2 deficit

TLDR

During exhausting exercise with low‑oxygen air (13.5 % O₂), maximal O₂ uptake falls 22 % while accumulated O₂ deficit remains unchanged. The study introduces a method to quantify anaerobic capacity by measuring maximal accumulated O₂ deficit. The method estimates O₂ demand by extrapolating the linear relationship between treadmill speed and submaximal O₂ uptake, using either ≥10 submaximal intensities or two near‑maximal measurements with a common Y‑intercept of 5 ml kg⁻¹ min⁻¹, and then calculates the deficit during a 2–3 min exhausting bout. The maximal accumulated O₂ deficit rises with bout duration up to 2 min, then plateaus; it varies 52–90 ml kg⁻¹ between subjects, has a precision of 3 ml kg⁻¹, and requires individualized running‑economy slopes that differ by 16 %.

Abstract

We present a method for quantifying the anaerobic capacity based on determination of the maximal accumulated O2 deficit. The accumulated O2 deficit was determined for 11 subjects during 5 exhausting bouts of treadmill running lasting from 15 s to greater than 4 min. The accumulated O2 deficit increased with the duration for exhausting bouts lasting up to 2 min, but a leveling off was found for bouts lasting 2 min or more. Between-subject variation in the maximal accumulated O2 deficit ranged from 52 to 90 ml/kg. During exhausting exercise while subjects inspired air with reduced O2 content (O2 fraction = 13.5%), the maximal O2 uptake was 22% lower, whereas the accumulated O2 deficit remained unchanged. The precision of the method is 3 ml/kg. The method is based on estimation of the O2 demand by extrapolating the linear relationship between treadmill speed and O2 uptake at submaximal intensities. The slopes, which reflect running economy, varied by 16% between subjects, and the relationships had to be determined individually. This can be done either by measuring the O2 uptake at a minimum of 10 different submaximal intensities or by two measurements close to the maximal O2 uptake and by making use of a common Y-intercept of 5 ml.kg-1.min-1. By using these individual relationships the maximal accumulated O2 deficit, which appears to be a direct quantitative expression of the anaerobic capacity, can be calculated after measuring the O2 uptake during one exhausting bout of exercise lasting 2-3 min.