Armstrong wins again in cycling

American cycling star Kristin Armstrong has won her third-straight Olympic road time trial gold medal - the day before her 43rd birthday.

Armstrong was the last rider to start and posted a time of 44 minutes 26.42 seconds in treacherous conditions over the 29.7km course at coastal Pontal.

Russian Olga Zabelinskaya was 5.55 seconds behind for the silver medal and women's road race gold medallist Anna van der Breggen was 11.38 seconds slower for bronze.

Australian Kat Garfoot finished ninth at a minute 8.61 seconds.