Originally Posted by SorrelHorse
Stop kicking her. Stop trying to "drive" her the entire time.
Selena came to me with this problem and at the barn I train for I get so many horses with the same problems.
You need to take the split reins, whip, spur, ANYTHING you can to make her go. Razzmitaz her. MAKE her move her feet.
My biggest thing here is that you said you keep driving her. Do NOT do this. Ask once softly. Ask a bit harder. Then finally get after her and make her think her world is crashing down no matter WHAT you have to do. Then, when she goes, stop driving. Let her go into an easy cruise control. The second she breaks down, get RIGHT on her again until she goes then relax. Stop riding. Loose rein. No kicking. No driving. That is her reward.
This is an issue that I'm currently working on with my horse. Part of the problem is that my horse is naturally a little lazy, and the other part is that my previous horse got me in the habit of constantly squeezing, driving, etc. which basically teaches the horse that the leg aid means nothing. He also shattered my confidence and I will sometimes catch myself leaning forward into a kind of "defensive" position- so even though I'm squeezing with my legs, my body language is telling him "don't go."
With my new horse, I'm focusing now on keeping my legs still except when I consciously want to give him a command. If he doesn't listen to a regular squeeze, he gets a little kick, if he doesn't listen to that, he gets a solid flick with the dressage whip. I'm also making sure I'm not blocking him with my body position. We've still got a ways to go (I've only had him 5 weeks!) but we're already vastly improved over when I first got him.