Getting better at tasks like walking, speaking and planning daily activities can improve a person’s quality of life after stroke. Research suggests that there is an optimal level of difficulty or challenge point where learning is greatest. Outcomes from stroke rehabilitation could be optimised if therapists and patients were able to accurately measure task difficulty during rehabilitation. This mixed methods study will explore the concept of rehabilitation task difficulty with people with stroke and rehabilitation therapists. This information will inform the development of a patient reported measure of rehabilitation task difficulty. The reliability and validity of the measure will be tested during different rehabilitation tasks in people with stroke. Lastly the feasibility of implementing the measurement tool and its impact on stroke rehabilitation will be evaluated. The findings of this research will support the optimisation of stroke rehabilitation to improve outcomes for people living with the effects of stroke.