2 things

[arq-dj1]

i was thinking about going up and down stairs, very fast with weight on my foot... would that improve my whole leg or maybe knees only?

and jumping, how much should i do?

 

[JoeBlack]

What are you trying to achieve?

if its running up and down stairs as fast as possible with weights on your foot, yes that will probably help lol.

Fill us in on what you are aiming to achieve and we can help.

 

[arq-dj1]

sure

im aiming to improve my dexterety, speed, the str of kicks to improve my kungfu moves...
also jumping can help gettin' fit and increase my vert

but im not sure at all, would u guys mind tellin' me if it works?

 

[Jariel]

It will definitely increase your stamina and fitness, but I remember reading a medical report some time ago that showed how step aerobics can damage one's knee joints, so I expect running up and down stairs could be risky in that respect.

 

[7 Virtues]

I would suspect plyometrics would be a far better system.