Armitstead, the Commonwealth road race champion and Olympic silver medallist in 2012, fell about 100 metres after the finish line as she celebrated victory and was given oxygen at the scene of the accident in Aldeburgh.
"Best wishes to Britain's Lizzie Armitstead who won has won stage one of the Women's Tour but has crashed after the finish line," British cycling said on Twitter.
Armitstead is the favourite for the race in the absence of the injured Marianne Vos and current world champion Pauline Ferrand-Prevot.
The Women's Tour is made up of five stages in eastern England.
(Reporting by Ed Osmond, editing by Ed Osmond)
Share
