This article seeks to establish an epistemological critique of the scientific discipline developed by Pierre Parlebas: motor praxeology. It mainly sets out the limitations of the latter in the definition of the object of study (motor action), considered fundamental in sport and physical activities. The absence in its analysis of the time of the courses of action in practice is the main obstacle to a proper description of these activities. This circumstance will also lead to a narrow conception of the participants\u2019 capacity to act and their practical rationality. This will also affect its possible applications (for example, in instructional design). A return to the ethnomethodology approach to analysis of courses of action in games is put forward as a possible solution to such shortcomings.<\/p>\n\n