ROEMMICH, J. N., C. M. GURGOL, and L. H. EPSTEIN. Open-Loop Feedback Increases Physical Activity of Youth. Med. Sci. Sports Exerc., Vol. 36, No. 4, pp. 668–673, 2004.
Purpose: 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.
Methods: 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.
Results: 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·d−1 whereas the control group increased by 13 min·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).
Conclusion: 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.