Questions about physical activity captured overall phys-
ical activity participation (moderate and vigorous physical
activities) as well as park-based physical activity (park-
based weekly physical activity and park-based physical
activity during their last visit). Overall physical activity
questions were modeled after the behavioral risk factor
surveillance system questions measuring both moderate
and vigorous intensity activities [56]. Specifically, respond-
ents were provided with the definition of moderate physical
activity (i.e., activities that cause small increases in breath-
ing or heart rate such as brisk walking and gardening), and
the definition of vigorous physical activity (i.e., activities
that cause large increases in breathing or heart rate such as
jogging and heavy lifting), and were then asked to indicate
how many days per week and the total time per day they
participated in physical activity at each intensity level for at
least 10 min at a time. Minutes of moderate and vigorous
physical activity were generated by multiplying the number
of days by the number of minutes per day [57]. A combined
overall moderate-to-vigorous physical activity variable was
calculated by summing the minutes of moderate and vigor-
ous physical activities, using listwise deletion if either was
not answered. In addition to overall physical activity, par-
ticipants were asked to indicate the time their physical
activity occurs in a park or outdoor recreation area in a usual
week (which may include multiple parks and visits) as well
as time spent being physically active during their last visit to
a park [55].