Preliminary report of a concurrent validation of a 3-day diary with accelerometry in a Portuguese sample of adolescents

The purpose of this study was to cross-validate the 3-day physical activity diary proposed by Bouchard et al. (1983) in a Portuguese population. Criterion measures of physical activity were derived using the Computer Science and Application, Inc (CSA) 7164 accelerometer. The sample comprised 98 subjects (boys, n=44; girls, n=54), aged 13 to 16 years old. All participants were volunteers and they wore a CSA monitor for five consecutive days and completed the physical activity diary for the first 3 of those days. The physical activity diary was weakly (ranging between r=+0.28 and r=+0.38) but significantly (p≤.01) correlated with the CSA motion sensor. The results produced coefficients of correlation similar to those obtained in previous studies. These evidences claim for the need to consider physical activity and physical inactivity as independent and complexes variables