change in total physical activity (PA) time within an urban living adult sample, to test for
additive or substitution effects. Methods Participants living in the greater Seattle area were
assessed in 2008–2009 and again 1–2 years later (2010–2011). At each time point, they
wore accelerometers and GPS units and recorded trips and locations in a travel diary for 7
consecutive days. These data streams were combined to derive a more objective estimate of …
Purpose: We assessed the associations between a change in time spent walking and a
change in total physical activity (PA) time within an urban living adult sample to test for
additive or substitution effects. Methods: Participants living in the greater Seattle area were
assessed in 2008-2009 and again 1-2 yr later (2010-2011). At each time point, they wore
accelerometers and GPS units and recorded trips and locations in a travel diary for seven
consecutive days. These data streams were combined to derive a more objective estimate of …