So here's the situation--I've never been able to do a full push-up. A couple times I thought I could, but I found out later I was only lowering myself around 1/3 of the way I was supposed to. I'm currently working up to full push-ups, and yesterday I was able to do 27 consecutive incline push-ups.

Problem is, I still can't do a push-up. What's even worse is apparently I'm doing incline push-ups wrong--I tried some knee push-ups with the best form I could manage, lowering myself to the point where I'm barely not touching the ground, with core engaged, back straight, and all that.

I can do six knee push-ups in a row. That's it. I start shaking badly and it's really difficult to raise myself back up after only a few. At my last one I usually just fall.

I thought I was doing well--incline push-ups are supposed to be harder than knee push-ups, not easier!

My arm muscles are pretty solid, so I think the problem is my chest muscles. What am I supposed to do here, just start doing the measly amounts of knee push-ups I'm capable of until I can do a full push-up?