It is one thing to say that the character absorbed the blow and kept fighting. It is quite another to know what it feels like to take a sidekick to the ribcage, let the pain flow through ones body, and use the momentum to knee an opponent if the face. It also allows the author to learn what real warriors think, and how they respond.
For instance: according to Seifu Bronson of Mountain Warrior Kung Fu Academy the first five rules of martial arts are:
1) Get Away
4) GET AWAY!!!!!
5)Get a weapon
The very last thing a warrior wants to do is to come to blows.
Little tidbits like this can really help to enrich a character.