Blood lactate disappearance in endurance-trained men (ET) and untrained men (UT) was investigated by application of recovery exercise with high relative intensity. Blood lactate was measured in five male long-distance runners as ET and in seven male relatively active students as UT, using a cycle ergometer (60 rpm) . Two kinds of recovery exercise were performed at intensities of 70% and 40% Vo₂max for 20 min followed by main exercise at 90% Vo₂max for 3 min. The rate of blood lactate removal was calculated by linear regression of time (min) against blood lactate (mmol·l^-1) at 5, 10, 15 and 20 min during recovery exercise. Values of blood lactate at 10, 15 and 20 min during recovery exercise at 70% Vo₂max were significantly more reduced in ET than in UT (P<0.05, P<0.01) . There was, however, no significant difference between ET and UT during recovery exercise at 40% Vo₂max. The rate A of blood lactate removal during 70% recovery exercise was significantly greater in ET (0.2730±0.0920mmol·l^-1.min^-1) than in UT (0.0520±0.1010mmol·l^-1·min^-1) (P<0.01), but there was no significant difference in the rate between ET and UT during 40% recovery exercise. The rate B of blood lactate removal during 70% recovery exercise was significantly higher in ET (0.3770±0.08000 mmol·l^-1· min^-1) than in UT (0.1163±0.14416 mmol·l^-1·min^-1) (P<0.01), but there was no significant difference in the rate between ET and UT during 40% recovery exercise.
In conclusion, the present data indicate that endurance-trained men possess more pronounced capability for blood lactate removal during recovery exercise at high relative intensity.