Wrist Accelerometer Cut Points for Classifying Sedentary Behavior in Children.

Area of Science:

• Pediatric physical activity monitoring
• Biomedical engineering
• Behavioral science

Background:

• Accurate measurement of sedentary behavior (SB) in children is crucial for understanding health risks.
• Wearable accelerometers are commonly used, but their accuracy for classifying SB, especially using wrist-worn devices, requires validation.

Purpose of the Study:

• To evaluate the validity and accuracy of different wrist accelerometer cut-points for classifying sedentary behavior in children.
• To compare the performance of wrist-worn devices against hip-mounted devices and direct observation.

Main Methods:

• Fifty-seven children (aged 5-12 years) participated in a protocol with 15 activities.
• Nine ActiGraph (GT3X+) and two GENEActiv wrist cut-points were assessed against direct observation.
• Analyses included equivalence testing, Bland-Altman plots, and ROC-AUC to compare accuracy with ActiGraph hip and activPAL3 devices.

Main Results:

• The most accurate ActiGraph wrist cut-points (Kim) achieved good classification accuracy (ROC-AUC 0.85-0.86) and accurately estimated SB time in both age groups.
• ActiGraph wrist cut-points showed smaller mean bias in SB time estimates compared to the ActiGraph hip cut-point.
• The most accurate GENEActiv wrist cut-point (Schaefer) demonstrated lower classification accuracy and was not equivalent to direct observation.

Conclusions:

• Validated ActiGraph wrist cut-points offer comparable confidence for classifying children's sedentary behavior to hip-mounted ActiGraph cut-points.
• While wrist accelerometers show promise, the activPAL3 device generally demonstrated higher accuracy for sedentary behavior classification in children.