I am 64 and from the Netherlands and they taught me this when I was 17.. Shaolin Kempo. Only a few years with 2 lessons a week. I can still remember it all. Every lesson started with meditation with closed eyes and becoming aware of your surroundings and also staying aware of the energy of the people sitting next to you. Then the katas with sparring at the end of every lesson. It was a mix of people with different martial arts backgrounds who also trained shaolin kempo. Bruce Lee was not yet famous. A really powerful punch is done with the 2 nuckles next to the index finger. A pressure of a blood vessel punch is done with the first two nuckles. Push-ups on your knuckles to harden them. Learn to make a relaxed movement with your arm to your fist. The tension in the fist comes a microsecond before the impact. It is also learning to close your fist as quickly as possible. Like grabbing something or blowing out a burning candle with your fist. Hardening your fist and breathing during the movement is also important. But like I said, it was only a few years of martial arts for me. I can still remember it all. Keeping and using distance is very important in full contact. Only people like Mike Tyson can move fast enough in close range. The one who strikes has a speed advantage that is almost impossible to defend against. It is almost impossible to avoid that first blow. You have to meditate and learn full contact to keep your self under control with adrinaline in your blood.