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.

The purpose of the present study was to investigate the relationships between the peak running velocity, and aerobic and anaerobic capacity in incremental running in pre- and post-competitive season using eight long distance runners. Measurements were peak running velocity, VO_2max, running velocity and VO₂ at respiratory exchange ratio (RER) 1.0, and blood lactate after exhaustion in the incremental running test. Correlation analysis revealed that pre-season velocity at RER 1.0 and post-season blood lactate were both related to peak running velocity. Furthermore, change in peak running velocity was related to change in blood lactate between pre-and post-season. These results suggest that factors that probably influenced running performance change from aerobic capacity in the pre-season to anaerobic capacity in the post-season, and that running performance during the competitive season may be highly dependent upon anaerobic capacity.

To obtain a viewpoint concerning evaluation of endurance type of athletes, we investigated the difference in physiological responses between middle- and long-distance runners in an incremental running test. Measurements were VO₂max and time of its appearance, change of VO₂ from 1.5 min before exhaustion to exhaustion (ΔVO₂), heart rate (HR), and blood lactate after exhaustion.
Results were as follows.
(1) The time of VO₂ max appearance in the middle distance runners was earlier than in the long distance runners.
(2) VO₂max was significantly higher in the long distance runners than in the middle distance runners.
(3) Blood lactate after exhaustion and HRmax were significantly higher in the middle distance runners than in the long distance runners.
(4) Blood lactate after exhaustion was significantly related to ΔVO₂ (r =-0.660, P<0.05) .
These findings suggest that the endurance type of athletes could be evaluated from the time of VO₂max appearance, blood lactate after exhaustion and HRmax in incremental running, and that VO₂max appearance may be effected by high blood lactate accumulation.