The Decimus Lunius Luvenalis’ “Mens sana in corpore sano” is finding a second wind with the growing interest in physica activity (PA) effects on health and cognition. PA is known as health factor. Children are recommended to practice at least 60 minutes of moderate to vigorous PA a day to benefit from PA for health. However, in in Europe, children don’t reach the recommendations. Also, we have to underline that PA and sedentary behaviors are not diametrically opposed: a single person can be physically active and being sedentary (e.g., staying sitting at the desk for more than one hour) and so, being at risk. Fostering PA and struggling sedentary behaviors is a public health priority. More and more papers are interested in the PA- cognition link. PA can foster executive functioning (high level cognitive processes that permit to adapt ourselves to environment constraints) after a single bout of exercise and can foster their development through a regular practice. A little is known about which PA dimensions are to take into account or what is the minimal dose that foster executive functions. However, aerobic exercise and cognitively engaging PA appear to foster PA. As children present less effective executive functioning than children from passed generations and as these functions are linked to success in life, health and future well-being, it is crucial to foster their development in our children. The aim of our study is to design, carry out and conduct a process analysis of an in class PA program that would be able to counteract in class sedentary behavior habits and foster children executive functioning. In order to achieve this aim, we developed and set up a 12 weeks school based program of in class active breaks. 3 classes of French CE2 participate to the study. In this presentation, we will table how we built our program from scientific framework and how we adapted it pedagogically. Then, the process analysis will permit to discuss the program in term of feasibility and interest. As the study is still in process, we are not able to give you results in this abstract.