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Kinetics of oxygen uptake during decremental ramp exercise
1Laboratory of Human Movement Science, Faculty of Education, Hokkaido University, Japan. yano@edu.hokudai.ac.jp
Background:
The purpose of the present study was to examine the kinetics of oxygen uptake (VO2) during decremental ramp exercises after incremental ramp exercise above the anaerobic threshold.
Methods:
Triangle exercise consisting of incremental and decremental exercises, and trapezoid exercise in which a constant load was inserted between incremental and decremental exercises were carried out.
Results:
Blood lactate (La) increased in incremental phases during triangle and trapezoid exercises, and showed a further increase at constant work during trapezoid exercise. It significantly decreased during decremental exercise. Initial VO2 level during decremental exercise was significantly higher in trapezoid exercise than in triangle exercise. The VO2 level then exponentially decreased and later showed a linear decrease during both exercises. These VO2 kinetics were expressed by an approximate equation. The time constant expressing the exponential manner was about one minute on average in both exercises. The slope of the linearly decreasing phase of VO2 was significantly related to La at 100 watts during the decremental exercise.
Conclusions:
VO2 kinetics during decremental exercise after incremental exercise above the anaerobic threshold consists of at least three components: initial level, exponentially decreasing phase, and linearly decreasing phase.