Meet Wizard.  Wizard was a successful jumper and lesson horse but incorrect shoeing over time caused significant changes
in his feet and back.
Wizard had great feet as a foal and through age 5, when my really good farrier moved to Arizona. The new farrier seemed to not take as much foot off when he trimmed.
  Wizard's feet grew long, his back became deformed at the sacral joint, and he was refusing jumps and bucking.  His nice, smooth gaits had become rough.  He used to feel like jumping a cloud.  In August 2007 at age 7, Wizard was retired from the lesson program and the jumper ring.  He still ended up 3rd for the year in OHJA Local Beginner Jumper with a student.  I decided to forgo traditional shoeing and opt for a barefoot trimmer.  Wizard was turned out.

Wizard had not been making much progress when I switched to barefoot.  I was having all the horses trimmed once a month.  It worked for everyone except Wizard.  A friend of mine asked me if she could trim him more often, and we began a weekly trim schedule. I have to admit, I was skeptical that he would need to be trimmed in just one week, but he did.  It was amazing to see that he had put out enough growth to require her to use the nippers.  He was trimmed once a week for three months before we could back off to two weeks, and later to three, where we are now.  Wizard puts out more hoof than normal horses.  His half brother Klark is the same way.
Wizard's feet began to improve right away on the more frequent trim schedule.  His heels have expanded and his frog is about double in width to what it was a year ago.  I would test ride him every so often.  In 2012 he began heading to the jumps on his own.  As of 2013 he has rejoined the lesson program and is jumping 3' again.