Caught peak action well. I like the separation with background. Even better is the fact that you and your son can share your passions together - worth much more than any photo you take. You are a lucky man.
Here's one to add to the thread. This was a shot from my last national race I shot a few weeks ago. I used two off camera flashes synced with pocket wizards, one on front and one behind on the same side. ISO was about 800 shutter speed was about 40th of a second, F/5 flashes were set at about 8th power.