casting methods
 

I find if I vary my casts it seems to help. Overhand, sidearm, inside
cross body it seems to help.Not all of the casts use the wrist to the
same degree. The point about holding the rod to tight is a good one.I
know if you are doing a lot of hammering and hold the hammer to tight
it will hurt your arm.
Holding the rod tight may be on account of an anticipation of tieing
into a fish.