The primary aim of this study was to test the validity of two accelerometers, CSA/MTI WAM-7164 and Actiwatch®, against direct observation of physical activity using the Children’s Physical Activity Form (CPAF). CSA/MTI WAM-7164 and Actiwatch accelerometers simultaneously measured activity during structured-play classes in 3- to 4-year olds. Accelerometry output was synchronized to CPAF assessments of physical activity in 78 children. Rank order correlations between accelerometry and direct observation evaluated the ability of the accelerometers to assess total physical activity. Within-child minute-to-minute correlations were calculated between accelerometry output and direct observation. For total physical activity, CSA/MTI output was significantly correlated with CPAF (r = .72, p < .001), but output from the Actiwatch was not (r = .16, p > .05).
Louise A. Kelly, John J. Reilly, Sheila C. Fairweather, Sarah Barrie, Stanley Grant and James Y Paton
Sheila C. Fairweather, John J. Reilly, Stanley Grant, Arthur Whittaker and James Y. Paton
The primary aim of this study was to assess the ability of the CSA accelerometer to measure physical activity in preschool children. A secondary aim was to examine inter-instrument differences and the effect of accelerometer placement on output. Eleven subjects (mean age = 4.0 years, SD = 0.4) wore the CSA-7164 for a 45-min preschool exercise class. They were observed throughout the class, and their engagement in activity was quantified using the Children’s Physical Activity Form (CPAF). The effect of accelerometer positioning (left vs. right hip) was assessed in 10 subjects over 2 days. CSA output during the class was highly correlated with the CPAF score (r = 0.87, p < .001), and rank order correlations between the 2 methods were also highly significant (r = 0.79, p < .01). Differences in CSA output between left and right hip reached statistical significance (paired t, p < .05), but these differences were small and probably of limited biological significance. The CSA appears to be an appropriate tool for assessment of physical activity in preschool children, but further studies on stability of activity as measured by CSA, as well as its validity, are urged.