The student's motor engagement reflects his personal investment in achieving a goal that he has set for himself, or that has been assigned to him. The motor task is the main lever allowing the teacher to mobilize the student's resources, motivate him and promote his progress. This study is based on the theories of self-determination and contextual motivation. The objective of this study is to evaluate the practice time of middle school students during their engagement in motor tasks, to compare the motor investment between girls and boys in scheduled physical and sports activity and to analyze the impact of motor tasks on their engagement. The methodology is based on systematic observations made among students at Bernadette Bayonne in Brazzaville.The results show that the actual time devoted to the motor task represents on average 23.34% of the official time of the main part of the lessons. This investment depends directly on the quality and richness of the tasks proposed. Furthermore, the analysis shows that girls and boys present identical levels of engagement, contradicting gender stereotypes in PE.