Daily physical activity patterns from hip- and wrist-worn accelerometers.

Area of Science:

• Gerontology
• Biomedical Engineering
• Physical Activity Measurement

Background:

• Wearable accelerometers are commonly used to estimate physical activity.
• The location of accelerometer wear (e.g., wrist vs. hip) may affect the accuracy of these estimates.
• Understanding how wear location influences data is crucial for reliable physical activity assessment, especially in older adults.

Purpose of the Study:

• To investigate the influence of accelerometer wear location on physical activity estimates.
• To compare activity patterns recorded by wrist-worn versus hip-worn accelerometers.
• To examine the daily accrual patterns of physical activity across different accelerometer placements.

Main Methods:

• Utilized data from the aging research evaluating accelerometry (AREA) study.
• Participants (37 men, 47 women, mean age 78.9 years) wore accelerometers for 7 days.
• Accelerometers were simultaneously worn on both wrists and the right hip in a free-living environment.

Main Results:

• Wrist-worn accelerometers yielded significantly higher median activity counts (approximately 5x) and greater variability compared to hip-worn monitors.
• Despite differences in magnitude, the daily activity accrual patterns (morning peak, evening decline) were similar for both hip and wrist placements.
• The consistent pattern shape across locations supports the use of either for estimating total physical activity volume.

Conclusions:

• Accelerometer wear location influences the magnitude of recorded activity counts but not the overall daily pattern.
• Both wrist and hip placements are viable for estimating total physical activity volume in older adults.
• Analyzing activity patterns over time can reveal nuances related to wear location and population differences.