forearm and grip?
this is so basic, you'll not believe it..
stick out your arms straight, open and close your hands
vigorously.. open and close = 1 count.. count to 100...
see how tired your forearms are after that 
if got a small/light dumb bell at home can try this:
Place forearm on support parallel to floor. hold dumb bell palm
up. Flex wrist downwards and allow dumb bell to roll backwards/down
till it's at the edge of the fingers (as far as you can keep
holding on). Then close fist and flex wrist back up.
