A wealth of school-based interventions report on students' positive responses to the use of models-based practice in physical education. However, research that examines the effectiveness of models-based practice rarely reports on the fidelity of implementation i.e. when all of the characteristics of a model are implemented. The purpose of this study was to explore model fidelity in the use of the Cooperative Learning model. Action research and systematic observation (using the Cooperative Learning Validation Tool which acknowledged the key characteristics of the model) were used to confirm model fidelity. Consequently, the themes of "scaffolding student learning", "working together", and "deeper learning" could be directly linked to the authentic use of Cooperative Learning context. The paper concludes by arguing that when reporting on findings from empirical research on the use of Cooperative Learning we need to adopt a more robust approach in determining--through rigor and quality of research--the authenticity of implementation.