I think I would prefer this shot either fully black and white, or fully color.
Also, I think it would have been better as a vertically oriented shot, maybe from another angle, or maybe not. I don't like the composition too much, and that's the first thing that came to my mind, however, upon closer thought, I might suggest to include less takeoff and more landing. I like the action and what's going on in the shot, but the composition downplays how good a shot it could be for me.
Yes, there was a bit of camera shake. That can be remedied by not moving the camera while shooting.
However, what NorCalNomad was getting at was the blurred rider. To really freeze action like a mountain biker riding through the frame, you need shutter speeds of over 1/800th or 1/1000th of a second.
And as for freezing action with a flash- it has to be significantly brighter than the ambient light.
If the ambient light is nice and bright, and you expose for the ambient light and pop a flash, it won't do much at all. You have to underexpose the ambient light (the sun in this case) and fill in the missing light with your flash. THEN, it will freeze your shot.
The trouble with using a flash to freeze action on bright, sunny days, is that the sun is very bright on bright sunny days, and more often than not, your flash won't be powerful enough to do the job right. That is when you bring in multiple flashes, like somebody else already said. (can't remember who)
The trick is, your flash won't compensate the way you need it to if it's on an automatic mode. Plop your flash on full manual, choose a power setting between M and 1/64th, wherever you need it to be, and do work.