Have you played with the levels of this photo at all? I don't know if you're a purist regarding post processing of digital photos, but if you're open to fiddling with the levels, I think you could have some fun with this, especially bringing out the lines of motion. What do you think?
as much as everyone loves the multitude of headshots of gus, I believe you have a greater strength in your action shots. this is really ..different the horse is transitioning down FAST, and you've cuaght that with the clouds of dust and the intense rip and shape of his muscles in his forearms. this is a really great picture!