Background: Our study focuses on the work engagement in PE of French vocational high school students. Indeed, the work engagement of these students is a major concern of the teaching staff. The majority of these students have not chosen the vocational field to which they are assigned. This non-choice is one of the factors leading to disengagement from work and deviant behaviour [Arrighi, Jean-Jacques, and Céline Gasquet. 2010. "Orientation et affectation: la sélection dans l'enseignement professionnel du second degré." "Formation emploi" 109 (March): 99-112. doi:10.4000/formationemploi.2814]. In order to encourage the engagement of these students, the social support of the teacher appears to be an important lever [Tennant, Jaclyn E., Michelle K. Demaray, Christine K. Malecki, Melissa N. Terry, Michael Clary, and Nathan Elzinga. 2015. "Students' Ratings of Teacher Support and Academic and Social-Emotional Well-Being." "School Psychology Quarterly" 30 (4): 494-512. doi:10.1037/spq0000106]. Purpose: This article aims to show the contribution of mixed methods research [Creswell, John W. 2015. "A Concise Introduction to Mixed Methods Research." New York: Sage Publications; Smith, Brett, and Kerry R. McGannon. 2018. "Developing Rigor in Qualitative Research: Problems and Opportunities Within Sport and Exercise Psychology." "International Review of Sport and Exercise Psychology" 11 (1): 101-121. doi:10.1080/1750984X.2017.1317357] to a study conducted within the Course-of-Action Research Programme [Theureau, Jacques. 2006. "Le Cours d'action: Méthode Développée." Edited by Octares. https://hal.archives-ouvertes.fr/hal-01107065; Theureau, Jacques. 2015. "Le cours d'action : l'enaction & l'expérience." Toulouse: Octarès Editions. https://www.decitre.fr/livres/le-cours-d-action-l-enaction-l-experience-9782366300468.html]. It analyses the experience of French vocational high-school students in physical education over a school year to identify and understand the social support of the teacher in engaging the students. This enabled us to describe and understand the typical supports experienced by students to engage with the work. Methods: To do this, we completed the Course-of-Action observatory with the CASS-S questionnaire [Malecki, Christine, and Stephen Elliott. 1999. "Adolescents' Ratings of Perceived Social Support and its Importance: Validation of the Student Social Support Scale." "Psychology in the Schools" 36 (November): 473-483. doi:10.1002/(SICI)1520-6807(199911)36:6 < 473::AID-PITS3 > 3.0.CO;2-0] to study the most significant experiences of support for students in the classroom during three teaching sequences of the year. Ten vocational high school classes with difficulties in engaging in school work were monitored during three teaching sequences. The teachers monitored were experts in teaching in vocational schools and had the characteristic of being highly invested in supporting the success of students with task engagement difficulties. The collection and processing of heterogeneous data (qualitative and quantitative). The first stage consisted of quantitative data collection using the CASS-S questionnaire in order to identify the teacher's social support as perceived by the students. The second stage consisted of conducting self-confrontation interviews enriched with the questionnaire with students who had a high perception of their teacher's support in order to understand their engagement in class. The data was processed in two stages: statistical analysis of the scores obtained in the questionnaires and analysis of the students' verbatims by typification of the components of the experience. Results: The quantitative results showed a global perception of frequent and important class-wide teacher social support via the CASS-S questionnaire. Furthermore, a more in-depth analysis shows variations over the year. This overall analysis is complemented by qualitative findings that provide insight into the significance that students attach to teacher support in their engagement with school tasks. The analysis of students' experience shows different kinds of typical-support paired with: the valorisation of students' progress, the students' concerns, the game action of the teacher, and teacher knowledge, promoting their engagement. Conclusion: Our study shows the contribution of mixed methods in understanding the meanings that these vocational high school students give to the teacher's support activity in a classroom. This contribution is to the Course-of-Action Research Programme by means of an articulation of heterogeneous data respecting the subjective viewpoint of the actors, and the enriched self-confrontation interview as a methodological device to help students' verbalisation.