Untitled

....

Your technical choices were very good but the composition suffers from a couple of points. Cutting off the rider's helmet is generally distracting and should be avoided at all costs. More distracting here though is that you can't see the rider's face very clearly. When shooting jumpers it can be difficult to get a great shot at the peak of the horse's arc where the rider has a pleasing look on their face, but there are a few things you can do to try. In this shot the rider is looking to the left. Most riders will look ahead of them to the next jump, so positioning yourself on the path will improve your chances. My last point would be to include part of the jump. Even if it is only the top rail it will give your photo perspective.