Two hundred metres did it. Not even that. It was a couple days before a big mile race, and we were on the sixth of eight 200-metre reps. Rounding the bend in lane two, I was getting ready to straighten up and push for home, when something snapped. It felt as though someone had got to the back of my leg with a pair of pliers. I faltered, hopped, and tried to get back into some kind of a stride but found I couldn’t. It hurt too much. Out in lane eight, and subject to the inquiring glances of clubmates, I tried desperately to sound cheerful: “Not a biggie – be all right in a mo.”

Source: The loneliness of the injured runner – The Guardian