摘要：Objective: To present project design and baseline characteristics of a project promoting life-long physical activity (PA) in an elementary after-school program. Methods: The project incorporates a two group design with delayed treatment control. PA and context observations and surveys (n=533; grades 4-6; attitude, enjoyment, intention, subjective norm, confidence, PA behavior, and fruit and vegetable consumption) were conducted. Results: Students spend almost 90 minutes standing, sitting and lying down and less than 17 minutes in moderate and vigorous PA during the after-school program. Students were strenuously active 3.89 days per week, moderately active 3.12 days per week, and mildly active 3.06 days per week, and watched television or played video games for 3.71 hours per day during leisure time. Attitudes, enjoyment, intention, and subjective norms differentiated students in different stages of PA. Discussion: There is an opportunity for PA promotion during after school, and stage specific interventions are indicated to facilitate PA
关键词：physical activity; children; after-school; determinants; stage of change
