Hi, I've been taking lots of photo's at the skatepark (and the streets) of skateboarding but have run into a couple problems.

To start off I was using faster shutter speeds (1/1000 and above) to freeze the action going on. This worked out great, although at times, there was shadowing being placed on the faces of the subjects, and hats and caps weren't helping either.

So the next step was to get flashes involved. After reading, i found out that my D90 had a flash Sync speed of 1/200. So I've set my Shutter speed accordingly. (which worked great on the streets and in shade etc)

My problem is, that when i was taking photos at the skatepark today, in full sunlight, I set my camera to f11, 1/200 and had a flash firing. I have found that parts of the subject have motion blur.
http://www.flickr.com/photos/timatah/5056443476/

Could anyone suggest how i could go about getting rid of the motion blur in full sunlight using flashes to fill?