Retaining the professionalism of experienced teachers is important at a time when changing curricula require the integration of new subject knowledge. Through evaluation of Higher Still Physical Education in Scotland, Thorburn and Collins analysed the different ways in which experienced teachers implemented a challenging new curriculum. Only occasionally did rich student learning lead to high levels of authentic attainment. Further analysis presented in this paper argues that effective in-service programmes require recognition of the importance of new subject knowledge and teachers’ preferred models of in-service delivery if policy aims are to be achieved in practice. The paper concludes by highlighting how repairing the erosion in relationships between teachers and academics in teacher education institutions represents the best opportunity for progress, which is sympathetic yet critical, and which avoids the problems of general vagueness and short-term reductionism found in other areas of in-service provision.