Greenspace and children's physical activity: A GPS/GIS analysis of the PEACH project

Objective. To quantify the volume and intensity of children's physical activity after school in greenspace and elsewhere. Methods. Data were collected between 2006 and 2008 from 1,307 children aged 10-11 in Bristol, UK. Accelerometers and Global Positioning System receivers measured activity and location every 10 s (epoch) after school for four days. Data were mapped in a Geographic Information System with a greenspace dataset. Activity volume (accelerometer counts per minute), time in moderate-vigorous physical activity (MVPA), and the odds of an epoch being MVPA (using logistic regression) were compared for greenspace, non-greenspace and indoors. Results. 13% of monitored time was spent outdoors (2% in greenspace), during which time 30% of activity volume and 35% of MVPA was accumulated. 7% of boys' activity volume and 9% of MVPA were in greenspace with girls slightly lower (5% and 6% respectively). The odds of an epoch being MVPA in greenspace relative to outdoor non-greenspace was 1.37 (95% CI 1.22-1.53) for boys and 1.08 (95% CI 0.95-1.22) for girls. Conclusion. Most activity occurring outdoors is not in greenspace and non-green urban environments are therefore very important for children's activity. However, when boys are in greenspace, activity is more likely to be of higher intensity. (C) 2010 Elsevier Inc. All rights reserved.