Background: In participatory research approaches, co-researchers and university researchers aim to co-produce and disseminate knowledge across difference in order to contribute to social and practice change as well as research. The approaches often employ arts-based research methods to elicit experiential, embodied, affective, aesthetic ways of knowing. The use of arts-based research in co-production in participatory research is embedded in a contested discursive terrain. Here, it is embroiled in political struggles for legitimacy revolving around what counts as knowledge and whose knowledge counts. Aims and objectives: The aim is to present and illustrate the use of a theoretical framework for analysing the complexities of co-production in the nexus between arts and research -- with a focus on the overarching tension between cultivating the collaborative, creative process and producing specific research results. The article maps out the contested discursive terrain of arts-based co-production, and illustrates the use of the theoretical framework in analysis of a participatory research project about dance for people with Parkinson's disease and their spouses. Methods: The theoretical framework combines Bakhtin's theory of dialogue, Foucault's theory of power/knowledge and discourse, Wetherell's theory of affect and emotion, and work in arts-based research on embodied, affective, aesthetic knowing. Results: The analysis shows "how" arts-based processes of co-production elicit embodied, emotional, aesthetic knowing and with "what" consequences for the research-based knowledge and other outputs generated. Discussion and conclusions: Trying to contribute to both research and practice entails navigating in a discursive terrain in which criteria for judging results, outputs and impact are often defined across conflicting discourses.