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Med Sci Sports Exerc. 2004 Apr;36(4):668-73.

Open-loop feedback increases physical activity of youth.

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Division of Behavioral Medicine, Department of Pediatrics, State University of New York at Buffalo School of Medicine and Biomedical Sciences, Buffalo, NY 14214-3000, USA.



The number of youth that meet activity guidelines is decreasing and easy access to reinforcing sedentary behaviors competes with increasing physical activity. In the laboratory, open-loop feedback that used pedometer activity counts to gain access to sedentary alternatives doubled physical activity. This study evaluated the influence of open-loop feedback and reinforcement on physical activity and television (TV) time in a small clinical trial.


Children (8-12 yr old) were randomized to an open-loop feedback plus reinforcement intervention (N = 11) or no feedback, no reinforcement control (N = 7). Subjects wore an accelerometer for 6 wk and attended meetings to download the accelerometer. Accumulating physical activity counts gave subjects in the open-loop group access to TV time, controlled by a TV Allowance device, with 400 counts = 1 h of TV. The control group had no feedback for activity and free access to TV.


The open-loop group had a 24% increase in physical activity, which was greater (P = 0.02) than the control group. TV time of the open-loop group was reduced by 18% or 20 min x d(-1) whereas the control group increased by 13 min x d(-1), but these were not significant changes. The change in time spent watching television was directly related to the change in BMI z-score (r = 0.69, P = 0.002).


Open-loop feedback increases physical activity in children, thus helping children to achieve physical activity recommendations. Reductions in TV watching may reduce or minimize gains in body weight.

[Indexed for MEDLINE]

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