King of the roads
Essex's Dominic King tells BBC Look East about his preparations for the 50km walk event at the London Olympics.
The 29-year-old from Colchester walks at speeds of up to 14kms per hour - faster than many people can run.
His twin brother and training partner, Daniel, failed to qualify for London 2012, but King hopes they can both make the team for Rio de Janeiro in four years' time.
"I feel like I'm doing this for both of us," he says.