A good way to train your body to take a hit is using the Boxer's medicine ball drill.
One or two people and one medicine ball. You can use a lighter 5 or 8lb ball one handed, or a heavier 12-15lb ball two handed. The two of you stand a few feet apart and lob or throw the ball at eachother's torso. Let the ball hit you, tense your muscles before the hit, take the hit, then when the ball rebounds, catch it and toss it back at your partner. Do it over and over, varying the parts hit. It works. The throwing motions also work the arm muscles for 'throwing or swinging' such as sword movements.
You can also throw the smaller medicine ball with your partner catching it in his hands and throwing back. Good hand/eye work as well as working those sword and shield muscles.
I have done this with my son and it works and is fun.
You can also do it by yourself. Lay down on a matt, and just toss the ball in the air and let it land on your torso, catch it before it rolls away and toss again and again.
Konradr