There are some good tips at the end of this article to avoiding armpump injury. Don't think our racing is violent enough to generate the forces needed, but the cross section through a forearm is a reminder of how complex the wrist is. Several DD riders have finished racing after wrist damage.
http://www.backontrackphysio.org/page7.htm pete
"Nearly all men can stand adversity, but if you want to test a man's character, give him power". Abraham Lincoln ...53 horse power should do it