This isn't a critique... but usually if I'm photographing something like this where motion is obvious, I usually compose the shot so the direction they are heading is open rather than where they have been. So I would have the horse and rider to the left of the shot rather than the right.
Is that just a personal preference on my part or was there a specific reason you composed the shot that way that has to do with one of these unspoken rules of photography that I pick up off the streets?
I was thinking the same: it looks like the horse is jumping out of the frame. You might be able to make the shot more intense by cropping it tight on horse and rider in portrait orientation.
This is just my two cents, but rules are made to be broken. I think there's plenty of space on the right, and the image is balanced by the negative space on the left. Plus, if you like rules, the Rule of Thirds was obeyed because the rider's head is at the intersection of the imaginary gridlines. Finally, the horse and rider are sharp, the scene is well-exposed, and the capture was made at exactly the right moment. Well done, Darson!