Interactive multimedia for promoting physical activity (IMPACT) in children.

OBJECTIVE To develop and examine the efficacy of a computer-based interactive multimedia curriculum for promoting physical activity in fourth grade children. RESEARCH METHODS AND PROCEDURES The participants were 209 fourth grade children (mean age of 9.5 +/- 0.4 years) from four schools. Two schools received an 8-week multimedia intervention delivered by interactive CD-ROM, supplemented by four classroom and four homework assignments. Two control schools received educational CD-ROMS not related to health outcomes. Measures conducted before and after intervention included height, weight, percentage body fat (bioimpedance analysis), physical activity (5-day accelerometry), and psychosocial aspects of physical activity by questionnaire. All outcomes were examined using general linear models. RESULTS There was a significant treatment effect for obesity reduction in girls but not in boys. There were no significant treatment effects on total physical activity by accelerometry (total counts per minute), but there was an overall treatment effect on reducing percent of time in moderate-intensity activity (16.5% to 15% of the time) and significant sex-by- treatment interactions for light-intensity activities (reduction in boys from 78% to 75% of the time and an increase in girls from 78% to 81% of the time). There were marginal/significant treatment effects for improvements in behavioral outcomes, including self-efficacy (p = 0.06), social norms (p = 0.07), and outcome expectancies (p = 0.049). DISCUSSION The interactive multimedia curriculum favored an improvement in obesity indices in girls and was associated with subtle changes in physical activity in girls and general improvement in psychosocial outcomes related to physical activity.