[twowheels]

A couple things - breathing denifitely helps, as does warming up before riding. Our promoters used to do sighting laps on which my arms would pump, but then I'd stretch out and they'd be fine by race time. Now I stretch and try to warm up the arms before the flag.

Second, I have run Pro Grip Rally grips - large diameter, reallt squishy, and they helped reduce arm pump as well (fist not as tightly clenched).

Third, standing as much as possible and flicking my fingers helps too.