This paper uses data from the healthcare sector to explore how clock time organization influences therapeutic performance. The case of a pediatric physiotherapist offers an important opportunity to examine how clock time, mediated by a variety of organizational and social systems, imposes limitations to the individual activity, in terms of learning, experimenting, and innovating. Social, cultural, institutional, and organizational layers have developed around this universal time reference. They impose an in-depth and taken for granted time discipline on organizational actors. The job of the physiotherapist conflicts with this clock time discipline when she has to respond to the evolving needs of her patients. Based on her expertise, the therapist decides on the necessary care, including duration and frequency of treatment. The measured time allocation imposed by the healthcare system and the time-based reward system generate pressure on, and interfere with, the unfolding activity. The study illustrates how the therapist escapes these multiple constraints and how this enables her to focus on the therapeutic acts. Taking the therapeutic process as temporal reference reveals the impact of clock time discipline on the unfolding therapeutic activity. I conclude that open-ended activities are inhibited and distorted by this socially constructed time not only because they cannot unfold but also because the temporal framing prevents deliberation and initiative.