The purpose of this review was to analyze the scientific production about extra-curricular physical activity (PA) in western children of 6-12 years. Medline / Pub-Med, Scopus and Google Scholar were used. This search collects articles published between January 1990 and May 2013. A total of 104 publications were analyzed. The body composition parameters are best used to assess the results of the studies, followed by those which estimate the maximum aerobic capacity. Articles of intervention are presented with very heterogeneous methodological features but there are clear trends in the use of certain aspects. As for the reviews, most are systematic and include meta-analysis. In this studies, body mass index (BMI) is the most used parameter.