This is the first part of my PhD research on the training of trainee teachers in Physical Education at the external Agregation. Candidates take a series of written papers. The candidates who obtain the best results in the written papers, then take on an oral examination. My research deals with the oral examination concerning the practice and analysis of a physical activity from a video recording of a physical performance. The main question of my research is : Is the video a relevant object of assessment in the training of Physical Education trainee teachers for the external Agregation in Physical Education ? Actually, I wanted to know how this particular and original oral exam was perceived and felt by the different actors concerned by this device.The choice of a framework about the sociology of the organisations according to Michel Crozier (1977 and 1979) and Michel Lecointe's assessment concept (1997) allowed me to develop my problems : how did actors (teachers and trainers) receive video in this exam? Were there reservations expressed on it by these actors ? What is the value of this oral exam among others in the external Agregation in Physical Education ? Does the creation of a Physical Education department in the "Ecole Normale de Cachan" (a grande ecole for the training of teachers) change the issues of the preparation which was reserved to the university departments in Physical Education ?My research methodology focuses on the assessment of a training device crossed by institutional issues and it is made up of four parts :- A study of the specificity of the external Agregation in France and, particularly, in Physical Education ; as well as a study of the status of video in the training of trained teachers through a historical approach and the study of official texts.- An analysis of exploratory interviews with a member of the jury specialised in video, two trainers from a university department of Physical Education and a candidate.- A study of the reports made by the jury of the external Agregation in Physical Education in these last twenty years.- The analysis of questionnaires given to the candidates of the external Agregation in Physical Agregation in 2004, 2005 and 2006 in order to make a comparative study of the results and measure the effect of the arrival of the candidates from the "Ecole Normale de Cachan".The following latest results reveal a gap between the original expectations of both the founders and the jury of this oral examination, and the candidates' skills concerning the use of video :- A misuse of video in the training of trainee teachers in universities- A depreciation of video in this examination- Theorical and technical learning difficulties in video- A lack of preparation and manipulation of the candidatesThese results point out many failures in this oral examination. They enable me to develop four hypothesis. First, the candidates would prepare themselves less conscientiously for this oral examination than for the other exams because it is weighted by a weak factor. Moreover, there would be a lack of coherence and means in the training concerning the material exploitation and the human potential of the trained trainee teachers at the university. Then, the arrival of the "Ecole Normale de Cachan" with its specific three years' course in video should improve the academic standard of this oral examination. At last, the university departments in Physical Education would have to react and improve their preparation.