Abstract Background: Chronic ischemic heart disease (IHD) is one of the leading causes of morbidity and mortality. Physical activity (PA) is an effective secondary preventive strategy in IHD management. The German IHD treatment guideline recommends that general practitioners (GPs) should deliver advice on PA to patients with IHD. However, this recommendation seems inadequately implemented, often due to GP’s insufficient specific training. International guidelines therefore recommend training GPs in how to deliver such advice effectively and efficiently. Currently, evidence is lacking on whether such training can enhance the frequency and quality of PA advice in routine care. The OptiCor project aims to develop and evaluate a training for GPs in the delivery of very brief PA advice to optimise the treatment of people with IHD in German general practice. Methods: OptiCor comprises three study phases over five years according to the Medical Research Council framework recommendations for developing and evaluating complex interventions. Phase 1 (needs analysis): A nationwide representative household survey will be conducted to collect data on receipt and type of GP-delivered PA advice in people with IHD. Focus group discussions and qualitative interviews with GPs and people with IHD will be conducted to explore, e.g. attitudes, motivation towards, experiences with, and barriers and facilitators of PA advice implementation or reception, respectively. The findings will inform the training development. Phase 2 (pilot): A pragmatic cluster randomised controlled trial (cRCT) on the effectiveness of the developed training on proportions of GP-delivered PA advice during routine care of IHD patients will be piloted. Phase 3 (evaluation): A full cRCT will be conducted with the patient-reported proportions of GP-delivered PA advice as primary endpoint. Health economic and process-related data will be collected to facilitate a potential future broad implementation and health economic evaluation of the training. Discussion: If the developed training successfully improves proportions and quality of GP delivered PA advice to patients with IHD, it could serve as a low-threshold and sustainable strategy for implementing PA recommendations in the secondary prevention of IHD in routine GP practice. This training could also potentially be transferred and applied to other chronic diseases or other health care settings. Trial registration: Most work packages (WPs) of this study build on each other over a period of five years. First WPs will inform the final design and methodology of the planned trials (pilot study (WP5) and main study (WP6)). WP5 and WP6 will therefore be prospectively registered with the German Register of Clinical Trials (DRKS) during the course of the project. The ongoing cross-sectional population survey (WP1) has been prospectively registered at DRKS (DRKS00031304, 19/06/2023).