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Published on: June 20, 2025
Estimation of oxygen consumption for moderate exercises by using a Hammerstein model
Steven W Su1, Lu Wang, Branko G Celler
1Human Performance Group, New South Wales Univ., Sydney, NSW, Australia. steven.su@uts.edu.au
Summary
This study models oxygen uptake during treadmill exercise using a Hammerstein model. The model accurately predicts oxygen consumption dynamics, aiding in designing exercise regulation control systems.
Area of Science:
- Exercise Physiology
- Biomedical Engineering
- Control Systems
Background:
- Oxygen uptake (consumption) during exercise is crucial for physiological monitoring.
- Accurate modeling of oxygen uptake dynamics is essential for effective exercise control and regulation.
- Previous models may not fully capture the nonlinearities and dynamics of oxygen consumption during treadmill exercise.
Purpose of the Study:
- To develop a block-structured nonlinear model (Hammerstein model) for predicting oxygen uptake during moderate treadmill exercises.
- To model the steady-state relationship between oxygen uptake and walking speed.
- To capture and represent the dynamic responses of oxygen uptake during exercise.
Main Methods:
- Collected steady-state oxygen uptake data from six healthy males at varying treadmill speeds (2-7 km/h).
- Utilized Support Vector Regression to establish the nonlinear static relationship between oxygen uptake and walking speed.
- Employed a Pseudo Random Binary Signal (PRBS) input on a computer-controlled treadmill to elicit dynamic responses.
- Analyzed breath-by-breath data to identify an ARX model for oxygen uptake dynamics.
- Integrated static and dynamic models to form a Hammerstein model.
Main Results:
- A nonlinear static function accurately represented the steady-state oxygen uptake-walking speed relationship.
- An ARX model effectively described the measured oxygen uptake dynamics within the aerobic range.
- The developed Hammerstein model successfully integrated static and dynamic components to predict oxygen uptake.
Conclusions:
- The established Hammerstein model provides a robust framework for predicting oxygen uptake during treadmill exercise.
- This model is valuable for the design of control systems aimed at regulating oxygen uptake during physical activity.
- The findings contribute to a better understanding of cardiorespiratory responses to exercise and inform potential therapeutic or training interventions.
