Educational reforms are currently under way in all curricular areas which call for teachers and schools to revise curricula, teaching strategies, and assessment practices; physical education is no exception. This study examined five of twelve physical education teachers participating in the Assessment Initiative for Middle School Physical Education (AIMS-PE), a reform based teacher development project designed to help teachers examine and reframe their assessment practices and to increase their students' knowledge and behaviors of physical activity. The purpose of this study was to examine teachers' experiences with change to understand how they used the espoused curriculum and assessments, and how they addressed project goals. Data included interviews with teachers, students, principals, assigned project researchers, and mentors from three schools, school artifacts, and descriptive field notes from observations. Interview transcripts and field notes were analyzed using open, axial, and selective coding (Strauss & Corbin, 1998). Results indicated that teachers from each of the three participating schools demonstrated, in varying abilities, adaptive approaches to implementation. First, teachers were provided opportunities to adapt project curricula and assessments to their particular situations and required a certain amount of negotiation and flexibility on the part of both teachers and facilitators. During implementation, teachers' abilities to adapt project materials proved to have a direct and powerful effect on the adoption of project goals and curricula. One teacher identified an ability to personalize new teaching materials and put a ‘spin' on them as important to her success, noting that materials were not meaningful until evaluated within her own teaching context. Second, factors which influenced teachers' efforts to adapt project materials included peer and institutional support, interactions with other teachers, opportunities to socially construct knowledge, sufficient time, and student reaction. Group discussions of instructional and assessment issues within the context of workshop sessions were also viewed as an effective way to gather new ideas and practices and represented a rare opportunity to interact with other physical education teachers. Finally, results indicate an importance for teacher development projects to assist teachers in becoming knowledgeable about change and empowered in their own ability to adapt to problems which may arise within the change process. Adaptive approaches to change, such as the one described in this study assumes that variability among teacher and schools is inevitable and that specificity of project methods and goals should evolve over time, paying particular attention to local conditions and individual needs. Keyword(s): professional development, research