IntroductionPhysical activity (PA) can improve cardiac function, exercise capacity, and quality of life, in addition to reducing mortality by 20%–30% and preventing the recurrence of adverse cardiovascular events in patients following coronary artery bypass graft (CABG). However, PA levels are low in patients after CABG. This study intends to explore the mediating effect of kinesiophobia between self-efficacy and PA levels in patients following CABG.Methods and analysisThe proposed study constitutes a prospective, multicentre and cross-sectional study comprising 413 patients. Four teaching hospitals with good reputations in CABG will be included in the study. All of them are located in Beijing, China, and provide medical service to the whole country. This study will assess the following patient-reported outcome measures: demographic information, International Physical Activity Questionnaire-Long, Social Support Rating Scale, Cardiac Exercise Self-Efficacy Instrument, Multidimensional Fatigue Inventory, Hospital Anxiety and Depression Scale, and Tampa Scale for Kinesiophobia Heart.Ethics and disseminationThis study conforms to the principles of the Declaration of Helsinki and relevant ethical guidelines. Ethical approval has been obtained from the Ethics Committee of The Sixth Medical Centre of PLA General Hospital (approval number: HZKY-PJ-2022–2). All study participants will provide written informed consent. Findings from this study will be published in Chinese or English for widespread dissemination of the results.Trial registration numberChinese Clinical Trial Register, ChiCTR2100054098.

IntroductionCardiac rehabilitation (CR) is a critical treatment for patients with coronary heart disease after percutaneous coronary intervention. Unfortunately, participation and adherence of CR are unexpectedly poor. This study aims to test whether low-intensity or medium-intensity brisk walking is more helpful in improving early attendance, adherence and physical results.Methods and analysisThis randomised controlled study will compare the effects of low-intensity and medium-intensity brisk walking to improve adherence and cardiopulmonary endurance. Participants will be randomly allocated to low-intensity or medium-intensity groups and will be followed-up for 8 weeks. Primary and secondary outcome data will be collected at baseline and at 2, 4 and 8 weeks. Primary outcomes measure changes in oxygen consumption (VO2) peak value (mL/kg/min), as well as adherence. Secondary outcomes include changes in body mass index, oxygen pulse, maximal metabolic equivalent, breathing reserve, vital capacity, ratio of forced expiratory volume in 1 s to forced vital capacity, Δoxygen consumption/Δwork rate (ΔVO2/ΔWR), minute ventilation/carbon dioxide production and self-efficacy.Ethics and disseminationEthical approval and informed consent form have been obtained from the Ethics Committee of Hebei General Hospital (approval number: NA-2021–03). The study background and main objective, as well as potential benefits and risks, will be fully explained to the participants and their families. Findings from this study will be published on academic journals in Chinese or in English for widespread dissemination of the resultsTrial registration numberChiCTR2100047568.