Objective Measurement of Physical Activity in Preschool Children: Comparison of Two Accelerometers Against Direct Observation

Measurement of physical activity in young children must be objective, since self or parental reports are not valid The advent of accelerometry has provided a practical and accurate means of objectively assessing engagement in habitual physical activity and inactivity (sedentary behavior) suitable even in young children. However; there is a paucity of data on physical activity in young children, in part because accelerometry has become available only recently, and in part because of limited evidence on the validity of accelerometers in young children Pre-school children, are thought to have movements which are highly transitory and more tortional. This might make the method of accelerometry important.

Purpose The aim of this study was to compare two accelerometers, the computer science and applications (CSA-7164) and Actiwatch, against direct observation of physical activity using The Children’s Physical Activity Form (CPAF)(O’Hara eta?., 1985).

Methods CSA 7164 and Actiwatch accelerometers simultaneously measured activity during 35-45 minute sessions of structured play in 78, 3-4 year olds. Rank order correlations between accelerometry and direct observation were used to assess the ability of the accelerometers to assess total activity. Within- child by minute correlations was also calculated between accelerometry output and direct observation.

Results Far assessment of total activity CSA output was significantly positively correlated with CPAF (r 0 72, p’cO 001), but output from the Actiwatch was not (r 0.16, p>0 05)

Conclusions The present study suggests that for epidemiological assessment of total physical activity in young children the CSA-7164 provides greater accuracy than the Actiwatch.