My mare has a weak right hind, and it is an old injury- it has always been weaker (for years). She had the last 5-6 months off from riding (the longest break ever) so it is really weak and giving out on her at the canter or trot. I have been riding a month now, 99% walk/trot, trying to strengthen it, but she keeps putting her haunches out to the right to keep her from having to use it correctly, or it occasionally gives out at the trot.
Other than it giving out occasionally, no pain signs are seen (head up, loss of roundness, etc). She doesn't have back pain, and her muscling is symmetrical on the left and right sides, however her right leg is a lot weaker, and she will not fully stretch/extend it, so it may be stiffer as well.

I found a veterinary service close by that offers chiropractic and accupuncture, and I plan on asking their opinion, but I wanted to get some of yours as well.

What do you think may work better in this case?

Anyone else have similar experiences with treating old injuries?

How often should it be repeated for effectiveness?

Approximate costs (I know it depends on where you live)?

thanks in advance!
Oh- it has been looked at in the past (a few years ago)- nothing was found to be wrong except for a slight stiffness and weakness. When she was in shape, it was a very minor problem that snuck up sometimes while circling. Now that she is out of shape, it is a major problem.
Time off of riding (6 months) made it a lot worse than when she was ridden regularly. She has had the old injury for at least 3-4 years, but it only popped up if she was sore (ridden 3-6 times a week for those 3-4 years). Now after the 6 month rest period, she is extremely weak from the time off with no work or muscling.

She is on 24 hr pasture board, so has been walking, cantering, and trotting on it on her own during the 6 months (and still).
As for diseases- I have dealt with Limes, EPM, West Nile, and Wobblers personally. She is not showing any of the same symptoms, and is just weak in the one leg- all of the neurological ones progressed or showed muscle atrophy in sections, while her same leg has been weaker for years now. The neurological diseases progress, and don't affect one leg, and then leave the muscling the same and not change anything else for at least 3-4 years.

i have a pinched nerve from my neck down to my back. explain these procedures to me and tell me why you choose that procedure. and how much do these procedures cost.

I had a foot condition. I asked my doctor if accupuncture would help and she said yes. I went in that direction and the condition was cured; the cost was 5. Would medicare cover this?

I'm moving to China for 1 year. Will I be able to easily find a medical doctor who can do accupuncture, in Chengdu? Any idea of how much this will cost? Thanks.