Now based in Colorado, O'Donnell has taken time out of her medical career to compete on the Pro-cycling circuit.

CNN: STORY HIGHLIGHTS

After an initial lay-off, she was forced off the circuit for a second time after being knocked out of the French Open in the second round.

BBC: SPORT | Tennis | Henin-Hardenne beaten on comeback

Thursday's rain-hit session at the Catalunya circuit saw Australia's Mark Webber record the fastest time after conditions dried out in the afternoon.

CNN: STORY HIGHLIGHTS