Training at the gym has become, without question, one of the most popular leisure pursuits in contemporary Western societies. In addition to conventional forms of fitness training with free weights, on machines or in exercise-to-music classes, more and more gym members decide to work out with a certified personal trainer on a one-to-one basis, often over long periods of time. The purpose of this ongoing study is to explore the relationship between personal fitness trainers and trainees with a focus on their subjective experiences. Eight semi-structured, in-depth interviews were conducted so far and analysed through a thematic analysis. Two central themes have emerged from the data: First, the trainer-trainee relationship is for both sides more than a transactional event but an emotionally significant encounter. Second, trainees describe an occasional reversal of roles where they show interest in and concern about the trainer. Future research should account for possible gender differences, changes of relational dynamics over time and possible negative experiences of both trainers and trainees.