By Susan Porter, World-Track

LONDON — Australia’s Jana Pittman-Rawlinson has been ruled out of next month’s World Championships and will not defend her 400m hurdles crown because of persistent back injury injury.

Pittman-Rawlinson, who recently returned to competition from a year-long sit-out has only raced twice this season and was almost on the road to defend her title in Berlin.

The quest, however, came to an end as the 26-year-old is now suffering from hamstring soreness which was diagnosed as being caused by a bulging disc in her back.

"Unfortunately the injury to my back has meant I haven’t been able to train properly for six weeks and despite intensive treatment," the Australian said in a statement from London on Sunday.

"It is still causing me a lot of pain and hampering my running.

"I will now continue treatment over the next few weeks before I head back to Australia, where I hope I can recover from this latest setback and get back on track for my long term goal and dream — winning the Olympic gold in London."

The injury was her second setback for two major season, following a toe injury that forced her to skip the Beijing Olympic Games last summer.