We have two terms to describe mechanical propeties: strength and toughness.
Strength is how much stress you can take in a push, pull, or bending motion. Lifting weights is a good way to build strength.
Toughness is energy absorption. Just because you're strong, it doesn't mean you're tough. Think Arnold Schwarzenegger (young) vs Bruce Lee. One way to build toughness is punching a concrete block. You can force your body to adapt and build tougher skin cells. Another way to build toughness is long exposure to the cold. The ancient Spartans and the Japanese used this technique to build overall toughness and body resistance. Flexibility also builds toughness.
Sitting out there in the cold will train your mind. That way, you can increase or decrease the temperature of your body at will, of course, that takes many years. It will also build willpower. There are some Tibetan monks that can dry their clothes in the Himalayan mountains by sheer will power. Crazy isn't it?
I against I,
flesh of my flesh,
and mind of my mind,
two of a kind but one won't survive,
my images reflect in the enemies eye,
and his images reflect in mine the same time,