AUTHOR=Llanos-Muñoz Rubén , Sevil-Serrano Javier , Lobo-Triviño David , López-Gajardo Miguel A. , Leo Francisco M. TITLE=Randomized controlled trial protocol on enhancing students’ togetherness, relatedness, and interactions for learning in physical education: the TRI-PE project JOURNAL=Frontiers in Psychology VOLUME=Volume 16 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2025.1629158 DOI=10.3389/fpsyg.2025.1629158 ISSN=1664-1078 ABSTRACT=Grounded in Self-Determination Theory and the Conceptual Model of Cohesion, relatedness satisfaction and class cohesion have been positively linked to learning-related outcomes. However, the benefits for both teachers and students of a training program focused on improving Physical Education (PE) teachers’ relatedness-supportive behaviors and class cohesion have not yet been explored. This study presents the protocol for a training program designed to provide PE teachers with relatedness-supportive and class cohesion strategies, as well as to avoid relatedness-thwarting strategies. Consequently, this program aims to enhance teachers’ interpersonal style and students’ motivational and (mal)adaptive outcomes in PE lessons. A randomized controlled trial with a mixed-methods approach will be conducted as part of a three-wave longitudinal study. Between 8–10 secondary PE teachers and their students will be assigned to either the experimental group or the control group. The face-to-face training program implemented with experimental group’s teachers will consist of two group sessions, one group booster session, and two individual follow-up sessions. After completing the training, teachers will implement the strategies over approximately six months during their PE classes. Beliefs, feasibility, and intention to apply the strategies, relatedness-supportive behaviors, relationship satisfaction with students, class cohesion, motivational variables, and (mal)adaptive outcomes will be assessed in PE teachers and their students at three distinct time points: before the training program (Time 1), at the end of the implementation (Time 2), and 2 months later (Time 3). Additionally, a focus group involving all experimental PE teachers will be held at the end of the implementation (T2). The results of this study will help determine whether this type of training program can benefit both students and teachers.