Wow. Just... wow.
@ladolcevita
Forget physics formulas and definitions. When you're facing the kicking shield , all of that goes out the window.
If you want to hit hard, you've got to hit things. The heavier the better. Kicking shields and focus mitts aren't designed to increase power; they're designed to increase accuracy. Get a heavy bag. If you can't hang a heavy bag, get a freestanding bag like a Century wavemaster XXL or a BOB.
If all you've ever kicked is the air, your power being weak is expected imo. The mechanics of kicking the air are different than kicking an object. When kicking the air, you have to rely on your own muscles slowing your body down so you don't fall over. When kicking a bag, you rely on the bag absorbing the force to keep you from falling down.
Your body is probably used to slowing itself down rather than letting go and following through correctly. No other way to explain it other than hit a bag repeatedly and you'll feel exactly what I mean.
There are a lot of other things that can be robbing you of power too. One could be your distance from the shield. If you're too close or too far away, you're not in the sweet spot to hit with maximum power. Even if you have flawless technique, distance will easily make or break your power. Everyone's optimal distance is different, and every strike's optimal distance is different.
If your muscular strength is average (meaning not excessively weak) or better, the biggest thing you'll end up training is your nervous system. Hitting a bag will teach you to let go and strike through the bag. It'll teach you to recruit more muscle fibers. It'll teach you to loosen up certain areas and tighten up other areas, and when.
Again, hard to explain fully, but easy to feel once you get used to hitting a bag. It doesn't happen in one or two sessions, but it does happen. The more you hit the bag, the better you'll understand your body. The bag provides excellent feedback that pretty much nothing else can replicate imo.
When I first started hitting a bag, I had a ton of very weak kicks. I was shocked at how weak certain kicks were, especially front leg kicks. After a few weeks they were noticeably stronger. The more I kicked the bag, the stronger I got.
Sorry if I'm rambling. If you want to hit harder (kicks, punches or anything else), you need to hit heavy things. Not in a haphazard manner where you're going all out from day one, but in a progressive manner in which you're listening to your body.
