One of the conditioning exercises I was shown was tapping the limbs up and down with a stick. Don't need to inflict pain but it does make the body stronger. The most difficult area for me to protect is the stomach. Went punch for punch with the wife and I folded quickly. She does out rank me.You meed to harden your body to strengthen the limbs to take impact. All that ot takes to disable an ordinary person who doesn't train, is one good leg kick. Same with forearms. Muy Thai fighters are famous for kicking trees.