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Protocol for Objective Measurement of Infants' Physical Activity using Accelerometry
Luiza Isnardi Cardoso Ricardo1, Inácio Crochemore Mohnsam DA Silva, Rafaela Costa Martins
1Post-Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, BRAZIL.
Insights
For infants, accelerometry for physical activity measurement requires 2 days on the wrist or 3 days on the ankle. Wrist placement is more acceptable to infants and mothers.
Area of Science:
- Pediatrics
- Biomedical Engineering
- Physical Activity Measurement
Background:
- Accurate measurement of physical activity in infants is crucial for understanding development and health.
- Accelerometry is a common method, but optimal protocols for infants are not well-established.
- Device placement and duration of measurement impact data reliability.
Purpose of the Study:
- To determine the minimum number of measurement days for reliable infant physical activity assessment using accelerometry.
- To compare the reliability and acceptability of wrist versus ankle accelerometer placement.
- To evaluate accelerometry methods for infants' physical activity measurement.
Main Methods:
- A cross-sectional mixed-methods study involving 90 infants.
- Physical activity measured using Actigraph GT3X+ accelerometers on the wrist and/or ankle for 7 days.
- Intraclass correlation coefficient (ICC) and Bland-Altman analysis to determine minimum measurement days.
- Qualitative interviews assessed device acceptability.
Main Results:
- For infants capable of walking, 2 days of wrist measurement or 3 days of ankle measurement achieved an ICC of 0.80.
- Infants not yet walking required only 1 day of measurement for similar reliability.
- Wrist placement was reported as more acceptable by infants and mothers.
Conclusions:
- Two days of wrist accelerometry or three days of ankle accelerometry are sufficient for reliable physical activity measurement in infants who can walk.
- Wrist placement offers better infant and maternal acceptability.
- These findings provide practical guidelines for optimizing accelerometry protocols in infant research.
Purpose:
This study aimed to evaluate methods for infants' physical activity measurement based on accelerometry, including the minimum number of measurement days and placement of a wrist or ankle device. We also evaluated the acceptability of the device among infants and mothers.
Methods:
A cross-sectional mixed-methods study was conducted on a convenience sample of 90 infants. Physical activity was measured using the Actigraph GT3X+ accelerometer placed on the wrist and/or ankle for 7 consecutive days (worn for 24 h), and a qualitative interview was performed to verify acceptability. The intraclass correlation coefficient (ICC) method and the Bland and Altman's dispersion diagram were used to verify the minimum number of measurement days. All analyses were stratified by walking status.
Results:
The mean (SD) age was 12.9 (1.70) months; the mean acceleration varied between 25.8 mg (95% confidence interval (CI), 14.3-52.7) and 27.3 mg (95% CI, 17.9-44.5) using the wrist placement, and between 24.9 mg (95% CI, 10.6-48.4) and 26.2 mg (95% CI, 11.7-65.6) using the ankle placement. The ICC results showed a lower acceleration variability between days among infants incapable of walking; they achieved an ICC of 0.80 with 1 d of measurement in both placements. Among those capable of walking, the minimum number of days to achieve an ICC of 0.80 was 2 d measured at the wrist (0.85; 95% CI, 0.71-0.93) and 3 d measured at the ankle (0.92; 95% CI, 0.84-0.96). The qualitative results pointed to the wrist placement as the preferred placement among the overall sample.
Conclusions:
Two and three measurement days with the accelerometer placed on the wrist and ankle, respectively, seemed to adequately represent a week of measurement. The accelerometer placed on the wrist had better acceptance by the infants and mothers.
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