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Visualization of Intensity Levels to Reduce the Gap Between Self-Reported and Directly Measured Physical Activity
Published on: March 7, 2019
Is measurement error altered by participation in a physical activity intervention?
Elisabeth Winkler1, Lauren Waters, Elizabeth Eakin
1The University of Queensland, School of Population Health, Cancer Prevention Research Centre, Brisbane, Australia.
Medicine and Science in Sports and Exercise
|November 30, 2012
Summary
Measurement error in physical activity tracking increased with higher activity levels. Intervention participation significantly impacted this measurement error, suggesting both self-report and device measures are needed.
Area of Science:
- Exercise Physiology
- Biomedical Measurement
- Clinical Trials
Background:
- Accurate measurement of moderate to vigorous physical activity (MVPA) is crucial for health interventions.
- Both self-report surveys and accelerometers have inherent measurement errors.
- Limited research exists on the agreement between these measures within intervention studies.
Purpose of the Study:
- To examine the agreement between self-report (Active Australia Survey) and accelerometer (GT1M) measures of MVPA.
- To investigate if intervention participation influences the difference (measurement error) between these MVPA measures.
- To assess measurement error in adults with type 2 diabetes undergoing a weight loss intervention.
Main Methods:
- Randomized trial comparing an intervention group (n=135) to a usual care control group (n=141).
- MVPA measured at baseline and 6 months using Active Australia Survey and GT1M accelerometer.
- Agreement analyzed using Bland-Altman and regression models; differences expressed as a percentage of average physical activity.
Main Results:
- Agreement between measures worsened as average MVPA increased.
- Measurement error differed significantly between groups at follow-up, not baseline.
- Intervention participation significantly altered measurement error over time.
Conclusions:
- Intervention participation affects the measurement error of self-reported physical activity relative to accelerometer data.
- The source of measurement error (self-report vs. accelerometer) is unclear.
- Measuring both self-report and device-based MVPA is recommended for future studies.
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