Physical activity pattern of children assessed by triaxial accelerometry

Objectives: Accelerometry was used to assess the relationship between the physical activity level ( PAL) and time spent on activities of various intensities in children. Design: A total of 20 children aged 8.6 +/- 3.3 y wore a triaxial accelerometer (Tracmor2) for 2 weeks. PAL was calculated with Tracmor2 output data. The fraction of time spent on activities with a given level of intensity ( low, moderate, high) was calculated. The fractions of time spent on activities of different intensities were compared with previously obtained data for young adults and elderly persons. Results: PAL showed an inverse relation with the percentage of time spent on low-intensity activities ( r = - 0.76; P<0.0001) and a positive relation with the percentage of time spent on high-intensity activities ( r = 0.93; P<0.0001). The fraction of time spent on low- intensity activities was smaller in children than in young adults ( P<0.05) and elderly persons ( P<0.0001), while the fraction spent on high-intensity activities ( P<0.0001) was larger. Conclusions: The present data are important for a better understanding of physical activity in children, which is necessary for education and prevention about physical ( in) activity in childhood. Our observations suggest that to obtain a higher PAL in children, they should be given the opportunities to perform high-intensity activities.