System Analysis for Oxygen Uptake Kinetics with Step and Pseudorandom Binary Sequence Exercise in Endurance Athletes

Abstract

We examined whether the system analysis for step and pseudorandom binary sequence (PRBS) exercises could be useful to characterize oxygen uptake (VO₂) kinetics of female sedentary subjects and endurance athletes. Breath-by-breath VO₂ was determined during step- and PRBS-cycle ergometer exercises. The time course of the VO₂ kinetics was evaluated by the time constant of the second phase, which should reflect the adjustment of the oxidative metabolism at the skeletal muscle level. The VO₂ kinetics were significantly faster in long-distance runners than in sedentary subjects for both exercises. A significant relationship was observed in the VO₂ kinetics obtained from step and PRBS exercises. In each group, there was no significant difference in the VO₂ kinetics for step and PRBS exercises. These results indicated that the system analysis with PRBS exercises revealed the faster VO₂ kinetics in endurance athletes than in sedentary subjects.

Key words:

• VO₂ kinetics
• PRBS
• modeling
• system linearity
• time constant
• exercise testing

ACKNOWLEDGMENTS

This study was supported by Grant-in-Aid from The Japan Ministry of Education, Culture, Sports, Science and Technology (13680024 to T.Y., 17770217 to D.A., and 16657076 to Y.F.).