The purpose of this study is to look at the effects of active video game play on youth physical activity.

Child obesity is increasing worldwide and has major implications for health, both during youth and later in life. Physical activity declines sharply during adolescence, making ages 8-12 a critical period to encourage healthy exercise habits. Increased childhood weight has been linked to sedentary leisure time activities, such as video games. "Active video games" (AVGs) are now being studied as a method to increase children's interest and participation in physical activity. Although research indicates that AVG play may lead to energy expenditure comparable to light/ moderate physical activity, children prefer sedentary video games to AVGs and often find AVGs boring. Children do not play AVGs as often or with the same intensity as traditional games/sports and lose interest in them; efforts must be made to increase the appeal of AVGs so they are competitive with sedentary video games. This study will examine whether children's motivation to engage in AVG play may be increased with greater autonomy, as well as whether increasing children's motivation to play AVGs also increases their motivation to play sedentary video games.

Inclusion Criteria:

• Sedentary lifestyle
• BMI between 5th and 95th percentile

Exclusion Criteria:

• taking any medications that affect energy use or eating
• actively trying to lose weight
• has any medical conditions that prevent him/her from safely joining in physical activity
• exercises more than three times per week for one hour at a time
• does not engage in more than 14 hours per week of screen-based activities
• does not own an active video game system
• plays active video games more than 30 minutes per week