US Population-referenced Percentiles for Wrist-Worn Accelerometer-derived Activity

Area of Science:

• Public Health
• Biomedical Engineering
• Kinesiology

Background:

• Objective measurement of physical activity is crucial for public health research.
• Wrist-worn accelerometers provide a feasible method for collecting objective physical activity data.
• Existing physical activity metrics lack standardization across different devices and populations.

Purpose of the Study:

• To establish age- and sex-specific percentiles for daily wrist-worn movement metrics in US youth and adults.
• To provide a standardized reference for total activity volume using Monitor-Independent Movement Summary (MIMS)-units.
• To enable comparisons of physical activity levels across diverse demographic groups.

Main Methods:

• Utilized accelerometer data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 and National Youth Fitness Survey 2012.
• Calculated Monitor-Independent Movement Summary (MIMS)-units from raw triaxial accelerometer data.
• Employed Generalized Additive Models for Location Scale and Shape (GAMLSS) to derive percentile tables and smoothed curves for daily MIMS-units by age and sex.

Main Results:

• Included 14,705 participants aged 3 years and older.
• Youth demonstrated similar MIMS-unit activity between sexes; adult females generally exhibited higher activity than males.
• Median daily MIMS-units peaked around age 6 years (males: 20,613; females: 20,706) and were lowest in adults aged 80+ years (males: 8,799; females: 9,503).

Conclusions:

• Population-referenced MIMS-unit percentiles offer a novel method for characterizing total physical activity volume in US youth and adults.
• MIMS-units provide a standardized reference applicable across various wrist-worn accelerometer devices.
• Future research should focus on linking MIMS-units to activity intensity and health outcomes.