Excersises for powerful knees?

[ElbowTKO]

Are there any good excersizes for strengthing your knees for knee strike?

I have heard about doing situps to work your hip flexors, but then again it also hurts your lower back...

What excersises are there? Do I just raise my knees up really high when jump roping or hit the bags?

[Meguro]

If you bend your knees you'll decrease the pressure on your lower back. I also find that if I keep my back rounded, as opposed to flopping down and touching shoulder blades to the ground, my lower back doesn't hurt as much. Alternative exercises might include hanging from a chin-up bar or holding yourself up on a dip-stand doing knee raises, wearing ankle weights and doing knee strikes into a heavy bag or air shield and finally leg raises from a seated V position.

[Aodhan]

Are there any good excersizes for strengthing your knees for knee strike?

I have heard about doing situps to work your hip flexors, but then again it also hurts your lower back...

What excersises are there? Do I just raise my knees up really high when jump roping or hit the bags?

Properly done, hip flexor situps should not hurt your back. Most people hurt their back because they round it and yank on their neck with their hands when they get tired. If you keep your back straight, you shouldn't have a problem.

Any exercise against resistance that bends the legs at the hip will develop the flexors (which in this case are the quadriceps), and to some small part the lower portion of the abdominals.

So, hanging leg raises, hanging leg raises with weights, lay on your back and attach a cable to your ankle for a weight machine (Most good gyms will have cuffs that attach for this), etc.

Aodhan

[TheAnimal]

First and foremost, practice your knee strikes. On a bag, on a pad, whatever- thats what gets them powerful. After that, you need a strong overall body period, specifically a strong core. Any and all ab exercises you benifit from, deadlifts, squats, etc will all help.

Another idea is to get those ankle wrap things and attach it to a cable machine, and put on a small weight and actually move as if you were kneeing something. Its the same motion, only with a bit of resistance, which is a great way to train things.