Our smartphones are becoming an entanglement of health-related apps. This ongoing paper tries to investigate how the smartphone carries the body into data flows that are embodied in self-tracking practices aimed to the self-knowledge. The theoretical-interpretative framework draws on the turn to practice, the embodiment and embodied knowledge; new relational materialism, with particular reference to the feminist onto-epistemology of Barad; and a sociomaterial perspective on the medical field as relates to self-tracking practices. We present the user's experience of a privileged witness in order to investigate how her Smartphone becomes a digital space by which body comes to matter. This empirical example tries to capture the process of embodiment by which the knowledge inscribed in the app is situated in everyday practices.The apps suggest a certain knowledge, that is reconfigured by humans using and/or not using some functions and options. This knowledge becomes a biomedical knowledge since it emerges across the tensions between the personal and tacit knowledge about how the biology of life works and, at the same time, the medical knowledge that is inscribed in the app.The paper is constructed around two concerns: (1) how the body learns “to be affected” through the material entanglements between humans and apps, and (2) how self-tracking technologies are engaged in the process of embodied knowledge
