Pymer, Sean, Harwood, Amy, Ibeggazene, Said, McGregor, Gordon, Huang, Chao, Twiddy, Maureen, Nicholls, Adam R., Ingle, Lee, Carroll, Sean, Long, Judith, Rooms, Marjorie, Chetter, I. C., "high INtensity Interval Training In pATiEnts with intermittent claudication (INITIATE): protocol for a multi-centre, proof-of-concept, prospective interventional study", BMJ open, 2020