Technical note: MR-compatible pedal ergometer with electromechanical pedal resistance and exercise triggering...

Area of Science:

• Biomedical Engineering
• Magnetic Resonance Imaging
• Exercise Physiology

Background:

• Dynamic 31P MR parameters are typically measured using MR-compatible ergometers.
• Custom-built equipment can be developed for specific local needs.

Purpose of the Study:

• To develop a pedal resistance ergometer with rocker arm functionality.
• The system integrates electric weight displacement, visual self-monitoring, and exercise triggering.
• Testing focused on the repeatability and reproducibility of the ergometer's performance.

Main Methods:

• Hardware and software were constructed from commercial components in a home laboratory setting.
• Twelve volunteers participated in the ergometer testing phase.
• The system utilizes a potentiometer, Arduino converter, and PC-controlled video projector for self-monitoring.

Main Results:

• A fully automated ergometer was developed, allowing real-time adjustment of pedal resistance.
• The system enables both operator and subject to monitor pedal frequency and force.
• Reproducibility/repeatability tests showed coefficients of variation from 6% to 3.1% and intraclass correlation coefficients from 0.96 to 0.99.
• All components are located outside the MR room, preventing interference.

Conclusions:

• The ergometer has been successfully used for over a year, handling both stationary and variable loads.
• The system is user-friendly and can be operated by a single individual.
• The developed ergometer provides a simple and cost-effective solution for exercise studies using 31P MR spectroscopy.