There are multiple conditioning weights that you can wear on your hands/arms/legs/chest, and they to work somewhat, but they only help you get stronger if you wear them for a long time nonstop, like a week without taking them off except to sleep. The problem there is that immediately after you take them off (after the week) you have to perform rigorous physical activity at the same level of the weights in order for it to be most effective.
So lets say you're wearing your own body weight in weights, and you take them off. You'll essentially have a brief period of time where your body will be adjusted to the weights, and you'll be able to move much better than normal. The issue is that your body will then adjust to normal conditions, which would leave you at square one.
Kuroneko1/2 wrote...
Those seems a bit farfetched
But like Rock Lee's weight bracelets? I'm pretty sure they are effective. Since you have to use more effort to perform normal movements.
They're good for leg speed training, but not running speed. In other words, with the leg weights on, you could train your legs to move faster in a kick/DDR game/in general, but they won't help you run faster, as running requires more than just your legs moving.
Although they make you weaker, if anything, when you take them off. With my leg weights on, I have an extra 20 pounds of weight behind every hit, so that adds a good deal of force, whereas without them I can kick faster, but not as hard.