Comparison of accelerometry and oxymetry for measuring daily physical activity

Area of Science:

• Exercise Physiology
• Biomedical Engineering
• Public Health

Background:

• Accurate measurement of daily physical activity is crucial for health promotion and epidemiological research.
• Accelerometry is a promising, non-invasive technology for assessing physical activity.
• Validation against a gold standard like respiratory gas analysis is essential.

Purpose of the Study:

• To evaluate the validity of accelerometry in measuring energy expenditure during various physical activities in non-athletes.
• To compare accelerometry-based energy expenditure with direct respiratory gas analysis.
• To identify limitations of accelerometry in diverse exercise scenarios.

Main Methods:

• Forty-five non-athletes performed treadmill walking (varying speeds, strides, footwear) and cycling ergometry.
• Energy expenditure was measured using accelerometry and respiratory gas analysis.
• Statistical analysis included correlation coefficients and coefficients of variation.

Main Results:

• Strong linear relationship (r=0.97) between accelerometry and respiratory gas analysis during graded treadmill tests.
• Mean differences in energy expenditure ranged from -0.77 to 0.27 kcal/min, with coefficients of variation between 13.2% and 22.2%.
• Accelerometry showed inaccuracies with altered stride lengths and failed to record cycling activity; shoe type had no significant effect.

Conclusions:

• Accelerometry is a reasonably accurate and feasible tool for assessing physical activity in non-athletes.
• It holds potential for epidemiological studies and health promotion, despite limitations in capturing certain activities like cycling.
• Further refinement is needed to address individual subject variability and specific movement patterns.