I started with a short video clip of my pitching motion. I think went through the reference video and set key frames through the character. I'd say the motion is about 90-95% complete. It matches pretty closely but could use a little more tweaking if this was going to be used in a full-blown project.
It was a good lesson and opened my eyes to just how tedious the process can be. A clip like this would be very well suited to a motion capture studio, but believe it or not, I don't have a full mocap setup in my apartment.
"The Pitch" (678KB)