sore back

["MCShasa" <MCShasa@email.msn.com>]

I have a problem re-occuring this season that I don't know how to fix so I thought I'd ask the experts.  Some background - I've had this horse about 3 1/2 years and been competing in endurance and CTR with him for the last three seasons.  In mid summer, this year he started having a sore back after the competitions.  Midly sore just over the loins.  Never bothers him in training and not in every competition but in too many of them.  He always finishes strong and there's no trace of it until about an hour after the ride.  It's always gone the next morning.  I'm usually up on my feet, out of the saddle, at every pace except the walk and try hard to stay balanced and not interfere with the horse.  I feel like I'm doing a pretty good job of riding balanced but I might be wrong.  I've been using a Big Horn saddle for the last two years and I really like it.  It seems to fit him well in the shoulders and doesn't seem to be rubbing anywhere.  But something is wrong somewhere and I don't know where to start looking.

 

Barb