Australia's four-time Olympian Duncan Free has announced his retirement from rowing after succumbing to a long-term rib injury, Rowing Australia said on Sunday. The 2008 Olympic gold medallist in the men's pair was attempting to compete at his fifth Games in London next month but has been troubled by the ongoing rib cartilage issue. Free, 39, who was hit by a car while cycling last year, said although it was a tough decision to quit he was bowing out proud of his rowing career. "I am quite proud that I was able to come back from the accident and trial for the Olympic Team, as 12 months ago I was unsure if I would ever be able to row again," Free said in a statement from the Australian Institute of Sport's European Training Centre in Italy. "I gave it my best crack and hung in there for as long as I could, but the body couldn't keep up as we were running out of time." Free was on course to compete in London until he was hit by a car while cycling on Queensland's Gold Coast, sustaining a fractured right leg and resulting in longer term complications to his ribs. Free made his Olympic debut at Atlanta in 1996 in the men's quad scull, winning a bronze medal. He also competed in 10 world championships, winning two gold and two bronze medals.