The purpose of this study is to examine if short bouts of structured physical activity implemented within the classroom setting as part of designated gross-motor playtime will increase preschool-age children during-school physical activity level.

Most preschool centers provide two 30-minute sessions of gross-motor/outdoor playtime per preschool day. Within this time frame, children accumulate most of their activity within the first 10 minutes. This study is a cluster randomized controlled study designed to examine the effects of short bouts of structured physical activity implemented within the classroom setting as part of designated gross-motor playtime on during-school physical activity in preschoolers. Results from this intervention could provide evidence that a physical activity policy that exposes preschoolers to shorter bouts of structured physical activity throughout the preschool day could potentially increase preschooler's physical activity levels.

Inclusion Criteria:

• Attend one of 10 participating preschool centers
• Attend preschool full-time
• Children between 2.9 - 5 years of age on the date of baseline assessment

Exclusion Criteria:

• Did not have a condition limiting their participation in routine gross-motor playtime at preschool
• Unable to wear the activity monitor