A kayaker jokingly sent me a photograph of her foot on WhatsApp the other day. Just to make a painful point. We were chatting about the hard but invisible work that legs do during kayaking and the picture illustrated her effort. On her heel was a massive callus.

Thou Shalt Suffer is one of the original commandments of sport, an inescapable truth in the pursuit of physical perfection. Backs spasm, blisters rise and most athletes own a minor degree in nursing: Find tape, tear off a strip, apply to complaining part.