Everybody has heard about training while wearing weights in different parts of your body: ankles, arms, torso, etc.
There are many references in cartoons that treat about Martial arts like the episode where Rock Lee battles Gaara (Naruto) (1:45) showing a considerable improvement in speed, or when Goku trains with them while flying (Dragon Ball) (1:40).
Obviously removing the "superhuman" factor that those cartoons show, I'm strictly referring to the real world. I know I wouldn't be able to move at superhuman speed, but does training with weights actually improve my body's performance?
All I find are articles, blog posts, but nothing actually reliable, like medical studies or similar research.