I recently purchased ankle/wrist weights because I want to increase the power and speed of my kicks.

But then. . . someone told me they'd just end up tearing my legs up. Is this true? Then what can I do to further strengthen / heighten / increase the speed of my kicks?

I've already learned to do a full split, but I don't know what else to do to reach even higher.

You can work with the ankle weights, just do it carefully. Kick at a moderate speed.

Also, get in the gym and do some leg weight lifting. That will help, too.

I agree with the weight lifting, though ankle weights, according to some, have detremental, long term effects.

I would think another type of resistence you be a pool of water

wrist/ankle weight a a great way to increase strength and stability, however, i wouldnt throw on an ankle weight and start throwin kicks as fast or hard as you would without them, this could damage your joints. instead, but the weights on and move through the kicks painfully slow. this will increase stability, balance, power, and technique to some degree. but dont forget to go all out without the weights on a heavybag, or just throw some techniques out in the air.

if you want resistance for your technique at regular speed, i highly recommend getting resistance bands, where the resistance comes on gradually and is a lot safer for your joints. ive even heard of some people cutting a bicycle tire tube, tying one end to something stable and the other end to the bodypart of the technique u are practicing

There are many medical reports citing detremetnal effects of ankle weights

Never mind any damage a little weight on your wrists and ankles will do, it won't do much at all for your punching or kicking power because they don't resist the line of motion of any kick or punch.