Factbox: Olympics hurdler Allen Johnson

Factbox on American 110m hurdler Allen Johnson, who announced his retirement on Saturday at the age of 39.

Born March 1, 1971, in Washington DC.

Shoots to fame
* Johnson shot to fame in 1995 when he ended Colin Jackson's run of 44 consecutive sprint hurdles victories.

* He won the world indoor 60m hurdles title in Barcelona and the 110m gold in the Gothenburg world championships in the same year. In the following year, Johnson won Olympic gold in Atlanta after missing the world record by only by 0.01 of a second at the US trials.

* He followed up with another high hurdles gold at the 1997 world championships in Athens.

Injury slump
* Injury wrecked Johnson's 1999 season and, although he finished second in the US trials, he did not start in the Barcelona world championship semi-finals because of a calf strain.

* A hamstring injury in Japan prior to the 2000 Olympics hampered him in Sydney where he finished fourth in the final.

Return to form
* Johnson returned to his best at the 2001 and 2003 world outdoor championships in Edmonton and Paris, notching up his third and fourth world titles.

* In 2003 and 2004 the American emulated his world indoor success in Barcelona with gold in Birmingham and then Budapest over 60m. The win in Hungary was to be Johnson's last major victory and he fell in the opening round at the Athens Olympics in the same year.

* At the 2005 world championships in Helsinki, Johnson came third in the 110 metres hurdles and in 2008 he won silver over 60m at the world indoor championships in Valencia.