Don't know if I am worrying about nothing - my dog didn't seem in any pain.  I had been practising jumps and decided to put up a weave with plastic bean poles.  I am hopeless at the right hand weave and she was going through very slowly when at the last weave her leg seemed to jam away from her body.  She didn't fall or twist it - I can't understand what she did.  She hobbled a few steps on three legs with her leg still held away from her.  She seemed to just give it a little shake then stood on it again.  She didn't seem concerned and I walked her along to check if she was limping - she didn't.  I then took her back through my weave poles slowly without any further trouble.  I brought her back in the house then.  

Hi Ceejay
It's difficult to say what happened without seeing it, but from what you describe it could be her patella (patella luxation).   Our last dog suffered from this and as soon as we manipulated it back into place he could walk normally again without limping at all.

It can be a secondary problem for dogs that suffer with hip displasia or it can just be a patella problem - either way I think you are best going to the vets to get this checked out!

I should have said that it was her front leg that was affected.  So it was her shoulder joint.  She had a good run round the garden later.
Christine

sounds like she pulled or twisted something then - glad she is OK now!
Maria :)

I'm not sure if they can dislocate their front legs/shoulders or not?? But by what you describe,it sounds as iff something popped out of joint(dislocated),but managed to pop back in.. Youch!!