Moderate and vigorous physical activity intensity cut-points for the Actical accelerometer.

Area of Science:

• Exercise Physiology
• Biomedical Engineering
• Physical Activity Epidemiology

Background:

• Accelerometers are vital for objective physical activity surveillance, quantifying movement intensity.
• Accurate classification of physical activity intensity is crucial for health research and interventions.
• Existing cut-points for devices like the Actical accelerometer may require refinement for precise measurement.

Purpose of the Study:

• To establish validated physical activity intensity cut-points for the Actical accelerometer.
• To differentiate between moderate and vigorous physical activity intensities using accelerometry data.
• To compare the accuracy of derived cut-points against existing methods.

Main Methods:

• Thirty-eight volunteers (26 adults, 12 children) underwent a multi-stage treadmill protocol (3, 5, 8 km/h).
• Actical accelerometers were worn, collecting data in 60-second epochs.
• A decision boundary analytical approach was employed to derive intensity cut-points.

Main Results:

• For adults, moderate intensity was defined as 1535 counts per minute (cpm), and vigorous as 3960 cpm.
• For children, moderate intensity was 1600 cpm, and vigorous was 4760 cpm.
• The derived cut-points demonstrated improved physical activity intensity classification compared to mean values.

Conclusions:

• The validated cut-points are recommended for accurate physical activity intensity assessment in adults using Actical accelerometers.
• Findings for children align with and support previous research, reinforcing the utility of accelerometry.
• This study enhances the reliability of accelerometry for quantifying physical activity intensity across different age groups.