Olympics Rio 2016: GB race walker disqualified for 'bent knee'
Team GB race walker Dominic King was disqualified from the 50km race walk following three 'bent knee' warnings.
King was disqualified just before the halfway point while on target for a personal best time.
The rules of race walking requires the athlete to straighten their supporting leg as soon as it touches the ground - and to keep it straight until it has passed under the body.
There are officials on hand throughout the course to watch race walkers' form. They can issue a yellow paddle - which acts as a warning - or a red paddle if they are convinced the athlete is violating the rules.