This longitudinal study seeks to show if sport has an impact on the school results and also on cognitive functioning, and if this causal link is significantly important. An experimental group of 55 students that practice out-of-school sports, at a rate of 3 times a week and a reference group of 55 students that do not practice out of school sports, their age is between 6 and 10 years old, both male and female from an elementary schools of the town of Oran (Algeria), they were followed during 15 month (five quarters). The socio-demographic data were collected by a questionnaire intended for the students of the two groups, and the administrative school results at the end of each quarter. An intelligence test of the CPM (Raven's Coloured Progressive Matrices) was administered at the end of the fifth trimester to assess the main cognitive abilities in both groups. Students that practice out-of-school sports have general school averages and a significantly higher (p<0.05) level of intelligence than students that do not. As noted by many similar studies, the practice of a physical-activity and sport regular seem to have a very positive impact on the academic performance and also on cognitive functioning.