In order to analyze the psychological factors that affect the non practice, practice and maintenance of the physical activity in students of the National University of Colombia, some concepts of the health psychology and the sport psychology were integrated, and a theoretical construct which was evaluated with an instrument of measurement of psychological factors was determined. This instrument was constructed and applied in agreement with the characteristics of this population and then, the interactions of the psychological factors that involve non practice, practice and maintenance of the physical activity in university students were analyzed and diagnosed, obtaining as a result the scores of the participants in each of the seven stages of the PAPM (Precaution Adoption Process) by Weinstein, related to the variables of age, current academic semester and academic faculty, laying the foundations for an intervention proposal that promotes the practice and reinforces the maintenance of practice of physical activity in this population.