Feasibility and Costs of Monitoring Physical Activity in Young Children Using the Caltrac Accelerometer

Monitoring of physical activity among 3- to 7-year-old children was achieved with an electronic motion sensor, the Caltrac accelerometer, for 1,666 days (of 2,030 scheduled) over a 2-year period. Failure of the monitor averaged once for each 45 days of successful monitoring. The total cost of devices, repairs, and batteries over the 2 years averaged $1.31 per day of successful monitoring. It is concluded that use of the Caltrac accelerometer is a feasible and relatively inexpensive approach for monitoring physical activity in young children in epidemiologic studies.