Fibromyalgia - Cantering kills my back

So I’ve been back into riding for a few months now. It’s be amazing so far, exercise without setting off fibro flares, my core is starting to return, etc. I can trot until the cows come home and have started trotting cross-rails and cavaletti which have been amazingly fun.

However, we’ve started adding more cantering in my lessons, and boy does it kill my back (lower back AND shoulders are so stiff and painful!). I’m working on not over arching my middle-back, which I do to try to keep “straight” in the saddle (what feels straight, it looks so stiff and uncomfortable when I watch myself ride). I know I need to get my core strong as that’s where I have to keep myself straight… it’s just not there yet.

Ideas? Tips? Thoughts? We’re having Alexa Derr (dressage with stretchy bands to help with position! She’s the one who pointed out my back is over arching to try to keep straight) out in January that I’m hoping to get some help from her then but any thoughts would be fantastic!

Solution Found! (Just in case someone comes across the same problem)

I was fighting against myself, knowing I have 3 areas to work on (arms too far forward/in, shoulders rolled forward, and over arching of the middle back) and was WAY overly tense in the saddle.

Solution? Ride one handed with the other holding onto the pommel. As soon as my shoulder/arm relaxed to my side my seat and lower back immediately softened. I managed to “graduate” to one arm at my side where it should be (pretending to hold a rein), but as soon as I had the reins in both hands my body tensed and everything went forward/fighting to sit up straight.

So it’s a completely mental thing that caused massive physical issues. At least I know how to fix it now before it becomes completely ingrained as a habit!