Introduction: The introduction of competence-based approach in international educational official documents has been justified by the development of more active learning methods to respond to social and equality challenges for students. Competence is defined as a situated activity composed of several components, especially knowledge built in action that is transferrable between familiar contexts. Purpose: From an activity analysis in situation, the study investigated students' lived experience in learning situations proposed by the teacher when they seek to develop competences. The aim was to identify, from the students' point of view, (i) how they built and typified knowledge during each lesson of a teaching unit and (ii) how they perceive the role of artefacts in supporting this process of developing competences. Method: Based on the theoretical framework of course of action [Theureau, J. 2006. "Le cours d'action: Méthode dévelopée." Toulouse: Octarès], a case study was conducted in a French school with two students, Mary and Maisy (Both aged 14 years; changed names) during a unit of six lessons in table tennis. Three types of data were collected: the teacher's objectives for each learning experience in the unit; audio-video records of the activity of students and teacher; students' verbalizations during self-confrontation interviews after each lesson. Three steps were undertaken for data analysis: transcription of data and construction of a two-level protocol; identification of the components involved in the process of typifying knowledge (perceptions and knowledge) and their categorization; analysis of constructed and transferred knowledge with regards to the teacher's objectives to identify meaningful moments of typifying knowledge and to understand the role of artefacts in student learning. Findings: Three meaningful moments for the students are analyzed here. Two moments referring to knowledge built were expected by the teacher. One was related to 'exchanges quality improvement' with students by using a symbolic artefact (for counting the score) and the development of various learner perceptions. The other moment was related to 'services quality improvement,' by using a material artefact (a cone) to help develop good services. The third meaningful moment referred to knowledge that was unexpected by the teacher. It is related to the misuse of an artefact by the students (the time-out introduced by the teacher). This artefact focused the student on winning 10 points without typifying knowledge expected by the teacher. Those results show how students construct and typify knowledge in action from their perception of artefacts introduced by the teacher, to develop competences. Discussion: Those findings are discussed around the risk of 'over complexification' of learning designs through use of many artefacts for developing competences in PE; the importance of developing various perceptions in typifying knowledge; and the teacher's guidance for an appropriate use of artefacts for learning. Implications: The observations in this study raised questions over the conditions in which artefacts are introduced for helping developed competence in learners. Several implications are discussed, including the stability, number and shape of artefacts; the teacher's guidance for helping students in learning artefact use and the meaning they give in action, and the development of various perceptions to help typify knowledge.