Working with students in Physical Education has been through a change because of, according to research, indications that young people aren´t involved in physical activities as much as in the past. This means that the educational planning should adapt to the teaching to fit as many pupils as possible free of the cognitive and physical conditions. The purpose of this study is to examine how an SDT (Self-Determination Theory)-based intervention affect students ' motivation in gymnastics. The study aims to see how an experimental intervention affects a class in comparison with another more controlled gymnastics-lesson. In order to reach the result the study has used questionnaires before and after the intervention. The result of this shows little difference in motivation changes between the groups, but the study is sharing light upon other perspectives on how to consider the objectives and issues. These differences are discussed and conclude that the study opens up new discussions and potentially new ideas by implementing of SDT pedagogically and didactically as well as suggestions for further research that can provide further proof of the SDT as a motivational approach within other areas in Physical Education.