Increasing Youth Physical Activity: Neighborhood Environment Influences

Increased access to highly reinforcing sedentary behaviors in the home such as TV and
computers are associated with overweight in youth. Reducing these behaviors reduces
overweight and prevents increases in overweight in youth who are at risk, likely by
increasing physical activity and/or reducing energy intake. Reducing access to highly
reinforcing sedentary activities frees-up time and youth must choose to reallocate their
time between engaging in other, less reinforcing sedentary activities or physical activity.
Neighborhood environments that provide easy access to reinforcing physical activities such
as those at parks may result in greater increases in physical activity when access to highly
reinforcing home sedentary behaviors is reduced. The investigators have found in 3 data sets
of youth ranging in age from 4 to 16 years that the proportion of park and recreation area
to residential area within ½ mile of the child's home parcel (park and recreation index)
independently predicted the physical activity of youth. The investigators also found that
increases in physical activity when access to sedentary behaviors were reduced for 3 weeks
was related to park area within ½ mile of the child's home. The aim of this study is to
decrease access to home sedentary behaviors for 4 months and determine if changes in
physical activity habits are related to access to parks and recreation areas in the
neighborhood environment. The investigators propose to study 128 sedentary overweight male
and female 12-14 year-old youth recruited from parcels within Erie County, New York that
have a high or low park and recreation index. Groups will be matched on racial/ethnic
distribution and socioeconomic status. Subjects living at low and high park access parcels
will then be equally randomized to groups that reduce targeted sedentary behavior (TV,
computer use) time by 50% using TV Allowance devices placed on each TV/monitor in the home
or a control group that has the same experimental experiences including TV Allowance devices
placed on each TV/monitor, but programmed to not limit access to targeted sedentary
behavior. Subjects will wear both accelerometers and wrist-watch-type global positioning
systems to determine changes in the duration and intensity of physical activity in various
parcel types, including parks. The investigators hypothesize differential responses in
physical activity and the utilization of parks for physical activity. The group of youth
that live at parcels with high access to parks and that incur a 50% reduction in sedentary
behavior will have greater increases in physical activity, number of visits to parks and
will accrue greater physical activity at parks than youth in the other 3 treatment groups.
The investigators hypothesize that the alterations in physical activity will be mediated by
parent modeling of physical activity and individual differences in the motivation to be
physically active. The investigators hypothesize that there will be a main effect of
reduction in access to sedentary behaviors on energy and fat intake and percent overweight.