Another day, another run up Greenwich Park hill. Along with the cyclists and runners, this time there was a man with a tyre attached to a rope, attached to a body-builder-style belt round his torso. I watched him do a series of (punishing) shuttle runs up the steepest gradient, dragging the tyre behind him like some kind of weird tail or ball and chain. Bizarre. But probably highly effective! Not something I will be doing soon. He looked super-fit with wrap around mirror shades and not obviously clinically insane... Maybe you can be both though.