From Marvel Comics The Punisher Armory No 2
Training:
“Sometimes, just sometimes, I think I go too far. This harkens back to a time when someone tripped me and I went head-first into a bunch of garbage cans. I was stunned to the point of drooling. Not a pretty sight; nor what was then done to my head immediately after.
Ultimately, I discovered that it was possible to hit the ground, walls, even garbage cans just right so that there was no felt impact. I conceived of the need of training so that I wasn’t afraid of diving and landing on concrete; you can’t hesitate when you do this stuff.”
Published by Marvel Comics in The Punisher Armory No. 2, June, 1991