The Concentration of Physical Activity in Time and Space Among Youth Using Accelerometer Data

• Activity Number: 549
• Type: Topic Contributed
• Date/Time: Wednesday, August 6, 2014 : 2:00 PM to 3:50 PM
• Sponsor: Social Statistics Section
• Author(s): Steven Gortmaker*+ and Jessica Barrett and Angie Cradock
• Companies: Harvard School of Public Health and Harvard School of Public Health and Harvard School of Public Health
• Keywords: Accelerometer ; Physical activity ; Youth

Abstract

Through analysis of multiple data sets concerning physical activity among youth, we document the extent to which moderate and vigorous physical activity (MVPA) tends to occur and cluster in certain environments of youth, with a particular focus on school day and afterschool periods. The primary hypothesis is that MVPA and particularly vigorous activity clusters during structured physical activity time (e.g. physical education class). We use multilevel statistical models taking into account clustering of observations both within individuals over time and within settings. Environments studied include physical education classes, recess, school classes with and without movement breaks, afterschool and summer camps. Datasets: 1) Accelerometer data from nationally representative 2003-2006 NHANES; ages 6-19; N=2,548; 2) youth from six elementary schools in Boston, N=455, with detailed daily schedules; 3) youth from 20 after school programs in Boston, N=404 children; 4) 5 Boston summer camps; N= 153 children. Actigraph accelerometers were used in all the studies, totaling 13.6 million person minutes of observation. NCI software is used to define wear times and days.