I'm a school student, and ever since i ended elementary and started jr high, i had an unusually heavy backpack (reason? i am too lazy to use my locker). At first, i barely could hold on the backpack b4 i collapsed my arms and let the thing down.. but after years, now i can't even feel it. And this got me thinking, if wearing heavy backpacks while ur playing can help u gain more speed. It's like playign with a squash racket to strengthen ur arm. After i played with my backpack, i would feel very light and move around the court much better(?) Did anyone have any experience with this? Is it a good idea, or is it just dumb?