9 August 2012 Last updated at 15:47

Olympics BMX: Crash causes seven-rider pile up

A massive pile-up in the first run of heat three of the men's BMX quarter-final results in an easy victory for New Zealand's Marc Willers.

A crash on the first banked turn brought down all the riders apart from Willers.

Manuel De Vecchi of Italy eventually rolled home in second place.

Watch a full replay of the men's BMX quarter-finals on the BBC Sport interactive video player.

Available to UK users only.