A 22-year-old rugby player was tackled six weeks ago, was told at the pitchside that it was just a sprain, and has been getting on with it ever since. He is still not right. He walks unaided, but he spends less time on the right leg than the left and cuts the push-off short, so the stride is visibly uneven. Asked to hop, he cannot leave the ground on that side at all; on the left he hops repeatedly without a problem.