Difference between self-reported and accelerometer measured moderate-to-vigorous physical activity in youth

We examined differences between objective (accelerometer) and subjective (selfreport) measures of moderate-to-vigorous physical activity (MVPA) in youth. Participants included 2761 youth aged 12-19 years. Within each sex and race group, objective and self-reported measures of MVPA were poorly correlated (R² = .01-.10). Self-reported MVPA values were higher than objective values (median: 42.4 vs. 15.0 min/d). 65.4% of participants over-reported their MVPA by ³5 min/d. The difference between self-reported and objective measures was not influenced by sex, age, or race. There was, however, a systematic difference such that inactive participants over-reported their MVPA to the greatest extent.