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Variability in measuring physical activity in children with cerebral palsy
Louise E Mitchell1, Jenny Ziviani, Roslyn N Boyd
11Queensland Cerebral Palsy and Rehabilitation Research Centre, University of Queensland, Herston, Queensland, AUSTRALIA; and 2Queensland Children's Allied Health Research, Queensland Health, and School of Health and Rehabilitation Sciences, University of Queensland, St. Lucia, Queensland, AUSTRALIA.
Measuring physical activity in children with cerebral palsy (CP) using the ActiGraph® GT3X+ accelerometer is reliable. This study confirms its accuracy in both controlled settings and daily life for children with CP.
Area of Science:
- Biomedical Engineering
- Pediatric Physical Therapy
- Movement Science
Background:
- Children with cerebral palsy (CP) often exhibit altered physical activity patterns.
- Accurate measurement of habitual physical activity is crucial for understanding health outcomes and designing interventions in this population.
- The ActiGraph® GT3X+ accelerometer is a common tool, but its measurement variability in children with CP requires investigation.
Purpose of the Study:
- To determine the measurement variability of habitual physical activity using the ActiGraph® GT3X+ accelerometer in children with CP.
- To assess the reliability of the accelerometer for measuring physical activity in controlled and community settings.
Main Methods:
- Independently ambulant children with unilateral CP underwent standardized physical tasks over two days, wearing an ActiGraph® GT3X+ accelerometer.
- Activity intensity was classified into moderate-to-vigorous physical activity (MVPA) using uniaxial-derived cut points.
- Intraclass correlation coefficients (ICC) and minimum detectable difference were calculated for repeated measures and community-based monitoring.
Main Results:
- Strong agreement (ICC = 0.80) was found between repeated measures for light physical activity and MVPA.
- Three days of community monitoring yielded acceptable MVPA variability estimates (R = 0.63-0.73).
- Spearman-Brown prophecy analysis indicated 3 days achieve 0.7 reliability and 11 days achieve 0.9.
Conclusions:
- The ActiGraph® GT3X+ accelerometer provides reliable measurements of habitual physical activity in independently ambulant children and adolescents with CP.
- The device is suitable for use in both controlled laboratory conditions and real-world community environments.
- These findings support the use of this accelerometer for research and clinical monitoring of physical activity in pediatric CP populations.
