Background: Less than half of children and adults meet physical activity recommendations. Effective interventions are especially needed to improve physical activity in African American females because they report less physical activity than their Caucasian and male counterparts. Objective: The aim of this study was to determine the effect of the Girls on the Go after-school program on the physical fitness of its participants. Methods: Half-mile run times for "Girls on the Go" participants were collected at the beginning of the program and three months later at the conclusion of the program. Only three participants were present for both runs. Results: Due to the small sample size, no statistical analysis was conducted, but there appears to be no significant differences between pre- and post-tests. Discussion: Possible explanations for the lack of change from pre- to post-test are discussed. The results of this study could be used to inform further research.