Recent studies have suggested that determining the accumulated oxygen deficit (AOD), in units of oxygen equivalents per kilogram body mass (ml O2 Eq.kg-1), during a short exhaustive run, may represent a non-invasive measure of anaerobic metabolism. However, there is little information either on the reproducibility of the laboratory determination or its relationship with human performance. The purpose of the present investigation was to determine the reproducibility of AOD during inclined treadmill running (study 1), and to examine its relationship with short-distance running performance (study 2). Twelve volunteers (11 males, 1 female) took part in study 1 and AOD was determined (relative exercise intensity approximately 120% VO2 max) on two separate occasions at a treadmill inclination of 10.5%; the laboratory-measured AOD values were 65.2 +/- 10.9 vs 66.3 +/- 12.5 ml O2 Eq.kg-1, respectively (r = 0.94, P < 0.01). A second subject group (10 males, 4 females) undertook study 2, which investigated AOD values and track times over 100, 400 and 800 m. The mean calculated AOD value was 66.1 +/- 12.0 ml O2 Eq.kg-1, and the average track times were 13.6 +/- 1.3, 60.9 +/- 6.8 and 138.8 +/- 18.5 s for the 100, 400 and 800 m, respectively. The r-values for the relationship between AOD and track time were -0.88, -0.82 (P < 0.01) and -0.61 (P < 0.05) for the 100, 400 and 800 m, respectively. The results of the present study suggest that the AOD (ml O2 Eq.kg-1) is a unique and reproducible physiological characteristic which is strongly correlated with sprint capacity.