That Darn Stifle

We woke up to this...

It is cold and nasty and shows no sign of letting up.

Looks like I won't be going to the barrel racing tomorrow after all :(
I went out to catch Moon yesterday(boy did it take some effort to make myself do that, as sore as my back was) to just go for a nice easy ride at the arena. Thought I might trot around the barrel pattern a couple of times to see if his mind was on business again.
As Moon trotted that big circle around me to avoid being caught, I noticed that his right hind leg didn't seem to be coming up correctly.
Damn it-here we go again...

When Megan got home, I asked her to trot him off for me. I couldn't see anything. Thought maybe it was just because the ground was a little slick on top from the moisture. But when she circled to the right with him, there it was. He is not lifting his right stifle quite right and his right toe was dragging just a bit.

Now up until last year, this horse has never taken a lame step. He was like iron. But last April, I got a sobbing phone call from my niece saying that she didn't have a barrel horse to ride in the High School Rodeos her parents had entered her in(Long, stupid story). I don't lend my horses out lightly but in a moment of weakness I said yes...as long as I am there every time you ride him.

In the interest of brevity and to avoid going into a long drawn out family saga-Moon ended up with pulled stifle muscles. He got too strung out running and was not staying in his correct lead. When he would get about 2 strides from the barrel he would try to switch over. I watched the video of it and saw him catch his hind toes as he was trying to change and his hind legs just sort of hung there while the rest of him was still going forward. I am sure this is what did it, but it sure didn't look severe enought to have caused permanent damage. I gave him 60 days off and then brought him back rather lightly toward the end of last summer. I made one run on him and it was horrible. So I went back to the drawing board on his training and have been working on the various problems he has accumulated. There has been no sign of lameness since he was hurt. Until yesterday.
Although he was being a butt head on Wednesday, I was really careful about warming him up, taking breaks and a good cool down. I don't know if this is a strength issue or if there is permanent damage.
The changing out of his leads is something he has always done. His mother was the same way. They are very easy leaded horses and will switch with the lightest pressure or change of direction. The ground I worked him on was dry and shallow but not hard.
So if anyone has ever had experience with a stifle injury or knows of exercises to strengthen the stifle please let me know...