Interest in posthuman concepts and ideas, philosophies and theories has grown enormously over the last 25 years, and posthumanism is now one of the most vibrant and innovative frontiers in healthcare thinking. At its most basic, posthumanism is a philosophical approach that decentres the human and considers other non-human or more-than-human objects as equally important. But this description belies the many challenges posthumanism presents to the researcher. There are many competing approaches to consider, there is often opaque language to navigate, and there are many structural problems to overcome. In this paper we tackle three major methodological challenges: vitalism, or the question of what gives life to things; transcendence, and the substance problem; and correlation, or latent anthropocentrism. We consider how it might be possible to research with a process-based ontology in a world dominated by substance-based principles. And we conclude with four related recommendations: a focus on key principles, concept creation, deep reading and attention to ontological slippage, before reflecting on our own experiences researching walking for people living with persistent pain.