Background: My theoretical background draws on physical education (PE) clinical didactics. It questions the specific nature of this academic subject matter, how it is transmitted and how it is internalized considering teachers' individuality. I intend to describe and understand how newly qualified and experienced PE teachers interact with their pupils regarding a key skill necessary to build motor abilities, that is, placing the pelvis in retroversion. Purpose: My research questions were the following: (1) Are there similarities and differences between newly qualified and experienced teachers in their linguistic approach to this skill? What are their intentions and how do they interact?; (2) what effects of such approaches are perceived by the teachers and observed in pupils' response?; and (3) what prospects could be inferred regarding teachers' training? Setting and participants: Six PE teachers specialized in gymnastics were asked to participate, three of them being experienced teachers and the other three beginners. Research design and data collection: I used a didactical methodology that consisted first in conceiving a lesson plan and then negotiating it with the teachers who agreed to collaborate with the research. Research data comprised questionnaires, interviews and observation. I combined qualitative and quantitative approaches. By analysing both verbal and non-verbal communication, I collected information on the language turns used, on their semantical content as well as on the addressee of the discourse. Findings: The major results showed some regularities and differences between newly qualified and experienced teachers in their linguistic approaches to pelvic retroversion. Considering the regularities, I observed a sparse use of the skill despite the stated intentions of using it, and a tendency to further reduce its use from one lesson to the next. The technical register was seldom employed whereas, in a particular way, the teachers largely turned to the metaphorical register. Besides, among the six teachers, the linguistic approaches mainly focused on the result of action rather than on the actions to be carried out. I also observed a sparse use of the skill at the end of the lesson, during the self- and peer-evaluation phase. Considering the differences, the three newly qualified teachers favoured a combined, familiar and metaphorical approach, whereas the experienced teachers resorted to a combined, familiar and metaphorical approach that included demonstrations. Unlike the newly qualified teachers, the experienced ones made use of linguistic approaches relating to the ongoing processes. Lastly, the newly qualified teachers mostly spoke to the class as a group while the experienced teachers tackled the skill to be taught on a more individual basis. The analysis of the effects of linguistic approaches on pupils' response showed that, in both cases, most pupils progressed and that those encountering difficulties progressed better with experienced teachers. Conclusions: This report enabled me to infer some orientations likely to optimize teachers' initial and continuing training. (Contains 15 notes, 11 tables, and 10 figures.)