Unfortunately we are unable to enrol everyone who wants to take part in the study. In order to answer specific scientific questions, and to ensure the safety and wellbeing of our study participants, we have to use a set of criteria against which people will be assessed for their eligibility. These criteria are specified below. If you are interested in taking part we would firstly ask you to complete some brief questions about physical activity. Based on these answers you would then be contacted by phone or email to make sure there aren’t any other reasons that you might be unable to take part.