Mothers the world over know best. Just ask Jennifer Bolt, the mother of Usain, the world's fastest man. Speaking in London , she said her son "might change things around a bit and try something new" for the 2012 Olympic  Games.

The 400 metres might be an option, so too the long jump,she said, although switching to a field event was less likely than simply extending his long legs one lap of the track. But she knows that keeping Usain interested in the sport, giving him new challenges, is the key to his motivation. Mrs Bolt, a former runner herself at 100m, 200m and 400m, said she first realised Usain's brilliance when he won the world junior 200m title in 2002.