Validation of the Tracmor triaxial accelerometer system for walking

Area of Science:

• Biomechanics
• Exercise Physiology
• Wearable Technology

Background:

• Walking significantly contributes to non-exercise activity thermogenesis.
• The Tracmor triaxial accelerometer is a validated tool for assessing free-living physical activity.
• Accurate estimation of walking energy expenditure is crucial for various health and performance applications.

Purpose of the Study:

• To validate the Tracmor triaxial accelerometer system for estimating the energy expenditure associated with walking.
• To assess the reliability and accuracy of Tracmor data across different walking conditions.

Main Methods:

• Subjects performed walking trials on a treadmill and level ground.
• Baseline variability of Tracmor output was assessed while standing.
• Tracmor output and energy expenditure were compared between walking modalities and with varying gradients.

Main Results:

• The Tracmor system demonstrated excellent reproducibility for standing (CV < 2%) and strong log-linear relationships between velocity and output during walking (r > 0.998).
• Energy expenditure during walking was comparable between treadmill and level ground conditions.
• Individual regression equations were necessary for accurate energy expenditure prediction due to response variance; gradient effects on energy expenditure were not detected by Tracmor.

Conclusions:

• The Tracmor triaxial accelerometer provides reproducible and reliable body motion data for walking, irrespective of whether performed on a treadmill or level ground.
• The system can predict walking energy expenditure, but requires subject-specific regression equations for accurate conversion of Tracmor output.
• The Tracmor system did not detect increased energy expenditure associated with walking gradients.