Supported exercise within transdiagnostic mental health services: a protocol paper for a two-arm hybrid effectiveness-implementation trial

People living with severe mental illness have a reduced life expectancy when compared to the general population largely due to physical health comorbidities. Exercise is a valuable, evidence-based component of mental healthcare, with positive effects on physical health, mental health, and quality of life. However, to date, there is limited evidence regarding the implementation of varied styles of supported exercise therapy within outpatient, transdiagnostic mental health services. This protocol paper outlines the methods for a hybrid effectiveness-implementation trial implementing two styles of supported exercise within an outpatient mental health hospital.