Lighting is pretty good. Composition works, but isnt anything special, try to incorporate more foground, also might wanna get lower. You will get much more (and better) Feedback if you post these up on skateperception rather then this dirthole for action photography
Personally these are pretty good shots, great action freezing. Although the background on the first 2 make it a little bit confusing, I tend to lose your subjects arms. Maybe try to cut down on the DOF to make some of the background blur a bit