This scientific research is related to the professional activity of swim coaches facing the introduction of TritonWear© technology (Triton). This artefact records a large number of parameters on swimmers’ practice – distance, split, stroke number, etc. – and sends them instantly to the coach’s tablet, at the poolside. Our hypothesis is that this technological artefact (Rabardel, 1995) influences the activity of coaches. How do coaches use this technology and the huge amount of associated data? What functionalities do coaches use and what obstacles do they face? How do they integrate Triton into their work? How does Triton transform (in case it does) the activity of coaches?