Well, not really. Actually, not at all. And then you fence, and no one gets killed. I am barely five feet tall and 100 pounds, but that does not stop me from doing well in this sport. Take, for example, a tournament I was in recently.
People can even fence from special wheelchairs.
Quickness and control are more important than strength. You have to be able to hit your opponent on his or her torso with what amounts to a long, flexible stick before he or she hits you, and keep the right of way. Right of way rules are complex and subjective, so you have to be able to keep track of who is moving where. Plus, each fencer is always trying to trick the opponent into leaving part of the target unblocked, making fencing similar to playing chess with nobody bothering to take turns. In this tournament I had managed to claw my way up the ladder to the gold medal bout by defeating mostly bigger, stronger and slower people.