The purpose of the present study was to investigate the effect of lactate accumulation on oxygen uptake immediately before exhaustion during anaerobic-aerobic maximal running. The present study focused on the relationship between change of oxygen uptake and blood lactate during the latter phase of maximal running. Eleven middle and long distance runners performed 4-min (submaximal) and 6-min (maximal) running at the same running speed. In a series of tests, oxygen uptake (VO₂), ventilation (VE), heart rate (HR), and blood lactate (LA) were measured. In addition, differences (Δ) between maximal and submaximal values in each parameter were calculated. AVO₂ was significantly related to ΔLA (r=0.670, P<0.05) . This finding suggests that increased oxygen uptake may be due to increased lactate accumulation during the latter phase of anaerobic-aerobic maximal running.