Growing up, I have always played sports. Handball was the first contact sport I had ever played. It's physically demanding and puts a lot of stress on the body. Many of the players wear knee pads and elbow pads to help prevent injuries.
One of the problems with most conventional sports padding is that they are bulky and uncomfortable. Armour pads use kerfing techniques, something that is typically seen on wood. The kerfing pattern allows the knee pad to sculpt itself around the knee.