Hockey/football equipment is too cumbersome. Have you thought of rollerskating or kickboxing pads? It won't protect from a faceplant down a flight of stairs (I just realized why they call them "flights"), but the knees and elbows can take so much beating and only need a bit of padding to get a minimum of protection.

That, or you could develop a PIC-based system with sensors and airbags placed at strategic locations.

Robert