Abstract: With so many truths about what effective endurance running coaching is and what it is not, it can be increasingly difficult for coach developers to navigate through these multiple interpretations to discern what is truly effective coaching. Recently, a group of Foucauldian coaching researchers mapped and critiqued the discourses and power relations that have come to shape endurance running coaches’ practices to show how coaches’ practices have become overly informed by disciplinary practices. However, as many Foucauldian coaching researchers have noted (Denison, Cassidy, Pringle, & Hessian, 2015; Denison & Mills 2014; Denison, Mills & Konoval, 2015; Mills & Denison, 2014), despite all of this critique no empirical work has attempted to understand what it might mean to change coaches’ use of disciplinary techniques and instruments (Foucault, 1995) in their practices. In light of this, the purpose of my thesis was to explore the impact of a Foucauldian-informed coach development collaboration with a university endurance running team. To do this, over a five-month period, I acted as a Foucauldian-informed coach developer to collaborate with one male university endurance running coach to develop and implement a number of Foucauldian-inspired coaching practices for his athletes. My thesis consisted of three papers that each provided different perspectives of the collaboration. My first paper aimed to explore what it might mean for a Foucauldian-informed coach developer to work collaboratively with Cliff (my coach participant) as he learned how to problematize the use of discipline. The results revealed that Cliff was able to show a degree of problematization by identifying some problems with disciplinary techniques in his practices, however, in the field, many of these practices proved too difficult to implement in a truly Foucauldian way. I argued that one reason why this may have been so difficult might be because the power of physiology, as the dominant knowledge underpinning what constitutes an effective endurance running coach (Mills & Denison, 2013), could have prevented Cliff from reimagining how he might coach without using disciplinary techniques that support a strong physiological orientation to coaching. My second paper explored the impact that less disciplinary coaching practices might have on athletes’ experiences. The results revealed that the continued presence of normalizing and objectifying processes might have prevented some athletes from understanding the full scope of the less disciplinary practices. As a result, simply implementing less disciplinary practices is not straightforward because Foucault’s knowledge is not made up of clear-cut, objective, verifiable truths, that can be simply communicated to athletes through one-way transactional pedagogies. My third paper aimed to understand what it might mean for a Foucauldian-informed coach developer to introduce and teach Foucault’s concepts to an endurance running coach. The results highlighted how finding ways to help Cliff make sense of Foucault’s knowledge can be difficult because social science knowledge is not seen as legitimate as most traditional sport science knowledges (e.g., physiology). In addition, negotiating Foucault’s knowledge can be perceived as questioning the ‘truthfulness’ of a coach’s existing practices, and by extension, threatening a coach’s identity. To conclude, I suggested Foucauldian-informed coach developers could development new strategies to delicately and constructively highlight inconsistencies that might surface throughout any collaboration. My thesis marked a significant moment in post-structuralist coaching research because it moved beyond mapping and critiquing endurance running coaches’ practices to explore the process of change using Foucault’s concepts in an applied setting (Markula & Silk, 2011). It has contributed to the Foucauldian-informed coach development research by identifying key challenges and barriers to teaching a coach how to coach in a less disciplinary way. Importantly, it showed that change is hard. Each of my papers illustrated the possibilities and difficulties that participants (i.e., coach, athletes, myself as coach developer) might experience when social-driven change is the goal. I conclude with a number of research areas for Foucauldian-informed coaching researchers to examine to help enhance the impact of future Foucauldian coach development collaborations.