Designing to support motivation is an increasingly important issue, especially as pervasive technologies are used to facilitate various healthy behaviour changes. There are many motivation theories but these do not map specifically to inform design. In 'Motivating Mobility' we explore the lived experiences of motivation of people with stroke, in order to design rehabilitation technologies. Motivation varies between people, between contexts and over time and can be 'difficult to express', particularly for those with communication problems. We describe development of a theoretically based toolkit, principled in both content and form, and using multiple modes of communication, aimed at gathering motivational requirements in order to inspire design. We show use of the toolkit, discuss the rich data collected and reflect on how well the approach works and ties requirements, via their elicitation tool, back to theory. This toolkit has potential to inform design for motivational effect in similar pervasive health applications.