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Difference between self-reported and accelerometer measured moderate-to-vigorous physical activity in youth
Allana G W LeBlanc1, Ian Janssen
1School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.
Pediatric Exercise Science
|January 19, 2011
Summary
Youth often overestimate their moderate-to-vigorous physical activity (MVPA) levels. Objective measures like accelerometers show significantly lower MVPA than self-reports, with inactive youth over-reporting the most.
Area of Science:
- Exercise Science
- Pediatric Health
- Biomedical Measurement
Background:
- Accurate measurement of youth physical activity is crucial for public health.
- Discrepancies exist between objective (accelerometer) and subjective (self-report) physical activity assessments.
- Understanding these differences is key to interpreting youth activity data.
Purpose of the Study:
- To compare objective and self-reported measures of moderate-to-vigorous physical activity (MVPA) in adolescents.
- To identify factors influencing the agreement between objective and self-reported MVPA.
- To examine the extent of over-reporting by different subgroups.
Main Methods:
- Analysis of data from 2761 participants aged 12-19 years.
- Objective MVPA measured using accelerometers.
- Subjective MVPA assessed via self-report questionnaires.
Main Results:
- Poor correlation (R² = .01-.10) between objective and self-reported MVPA across sex and race groups.
- Self-reported MVPA (median 42.4 min/d) was substantially higher than objective MVPA (median 15.0 min/d).
- 65.4% of participants over-reported MVPA by at least 5 min/d; over-reporting was greatest among inactive youth.
Conclusions:
- Self-report significantly overestimates youth MVPA compared to objective accelerometer data.
- The discrepancy is not explained by sex, age, or race.
- Inactive youth exhibit the largest overestimation bias in physical activity reporting.
