Robert Cheruiyot fulfilled most people’s predictions by winning the 112th Boston Marathon on 21 April. But it was not so much the fact that he won as the manner in which he did it that was remarkable. He absolutely destroyed the field through his front-running, and at times was running at near word record pace!

Many runners stretch diligently before, after, and (sometimes) during training, believing that regular stretching prevents injury and helps them recover after training. Yet some runners have never stretched a day in their lives, and never plan to! So who is right? What is the scientific evidence that stretching works?