it depends on the martial artist. although, I find Wing Chun and Jeet Kune Do to be extremely economical and efficient in a street fighting situation. these styles use many principles to practice, such as, Drawing, Recycling, Trapping, Non-telegraphic, direct attack, and indirect attacks. also with the particular styles strength and size do not play a vital role in the art. mostly in the sense that you are suppose to be as relaxed as possible with all your movements including punching. if you do some reading or watch some videos on this you will understand better why this is very effective.

~Kyle