First time was when I went to a seminar and the instructor kept having me repeat a front cross sequence that ended in the A frame. After a few times of this, Taylor decided: No more A frames.
Dumb of me to not see what could happen. To put him up to that. I trusted an expert, when I should have been trusting my dog.
Lesson is, never blindly do what someone tells you to do, if you feel it might not be the right thing for your dog.
After all, that person that sent us to climbing that A frame went home that night and slept soundly.
Me? I went home to a problem that would dog me the rest of my dog's career.
Bottom line: if you have a tiny toy dog, your dog has only so many full height A frames in them. So use them wisely.
Ration yourself to only a slim few per practice session. If you really need to train something, lower the darn thing down.
Yes, it's a pain. No, you can't lower that thing alone. But maybe you can trade off a favor with someone to get it done.
Work at a height that your dog is comfortable with. Work at getting them to power up it confidently, engaging their hind end -- a lot of little dogs will try to actually PULL themselves up with their front paws. This never works since the front of a dog is not as strong as the hindquarters.
So watch for them to engage the hindquarters on the climb and reward it.
Practice all kinds of approaches. Work on distance.
Then, slowly raise the monster up. Only if your dog is successful.
Repeat as often as necessary throughout your little dog's career.
Above all, don't get discouraged. Take it one step at a time. One inch at a time. And hopefully you'll get that monster tamed. At least for awhile.