Back pain from riding possible loan horse (no fall)

[jaymo63]

Hi, I'd appreciate some advice on this as I've never had pain like this from riding, and not sure if I should push through or find another opportunity.

I've ridden in riding schools for about 15 years and am a bit sick of it tbh, I feel like I make minimal progress and don't get to enjoy or learn about any aspects of horse(wo)manship beyond riding. So a loan opportunity came up on a local Facebook group, a 5yr old ex racer, gelding, very green but not dangerous or anything like that. His owner mostly wants me to do flatwork with him as he's recovering from an injury.

I went to ride him today and he was a bit wobbly/unbalanced, lacking in muscle. He was lovely to walk and trot. His owner pre-warned me that he had a very rocky canter, like sitting on a rocking horse. The problem was that when we started cantering on the left rein, I was tossed about so much that I pulled something in my back and had to get off pretty much immediately. I think it's a muscle strain, I'm having trouble walking, breathing, pretty much everything now. It was also pretty embarrassing to be in so much pain just from cantering!

This said, I do still really like the horse and I think if we worked on his trot and his overall strength then this canter situation could improve. Am I an idiot for not just walking away?! Is it madness to want to loan a horse that I can only exercise in 2 paces?
I've never loaned before.

Thanks!

Is it a full loan or a share ?

@Floralnomad it's a share, I'd be doing 2 days per week.

I know what you mean re the back pain, there is a horse at the yard I livery on that has a simply enormous canter that it's physically painful to sit to - problem solved pain wise by popping up into light seat/jumping position although that does tend to make him go on the forehand and unbalanced so not really a long term solution. He's a teenage warmblood also, not a young TB - that type shouldn't really have huge/extravagant movement so I wonder if it's something wrong in his confo or his injury/lack of previous schooling making him go that way.

TBH I don't think you really want a horse you can't canter long-term, and the whole scenario of green ex-racer, already injured at 5yo, has unusual movement/gait, owner wants you to school/improve it, you are more used to RS horses, that sounds alarm bells for me. At the very least it sounds as though you could spend a lot of time and energy improving someone else's horse - for me a share horse should be something you can enjoy and ride straight away without too much issue. I'd look for something else...

@maxelly I think you are right, thanks for your reply. I'm going back to the riding school in September, it's got an adjoining livery yard so I might ask there if there are any loans needed. This was the first time I've been to view a loan so there have got to be better ones out there!