Mark Webber broke his shoulder yet again with just four crucial races left to run in 2010.

In late 2008, after shattering his right leg in a mountain bike smash, the Australian hid from his employer Red Bull the fact that he also broke his left shoulder.

But with his injuries apparently fully healed, it recently emerged that Webber would miss the post-season Abu Dhabi Pirelli test due to surgery.

It was believed the operation was due to his 2009 pre-season breaks, but Webber has now revealed in a book that he was carrying a fresh injury into his recent charge for this year's title.

In his official book 'Up front: a season to remember", the 34-year-old revealed that he broke his shoulder again after returning to Australia after the Singapore grand prix in late September.

Once again, he crashed a mountain bike; this time when a friend fell in front of him.

Webber's injury is reportedly known as a "skier's fracture"; not serious but deep in the joint and difficult to treat.

The book said he declined to tell his boss Christian Horner, and that only his trainer Roger Clearly and FIA doctor Gary Hartstein knew about the injury and his cortisone injections in Japan and Korea.

The injury might explain Webber's crucial loss of form after leading the championship at the time of his accident by 21 points from Fernando Alonso.

And when he crashed, Webber was 31 points clear of his teammate and eventual champion Sebastian Vettel.

Gallery: Webber concealed a broken shoulder through 2010 finale

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