I bred a mare, my baby (now 4 1/2) who has a loooong back; her dam was my competition horse (medium length back), sire was an imported Hanoverian jumper bred stallion (medium length back), so :sigh: It is what it is! (Some long-lost WB relative several generations back was surely the “guilty party” in this throwback gene )
She also has a long neck, a long shoulder, and a fairly long hip. At around 15’1’, 15’2", not a big horse!, but she stands over a lot of ground.
I do all of the bodywork mentioned by another poster: belly lifts, butt tucks, backing up hills, LOTS of core work exercises to strengthen and supple her, and Hillary Clayton’s “build your horse’s core” is my bible. Her back is in good shape (well, she’s young!), but I can see the “long span” getting weaker with age - so I do everything I can to work on keeping it healthy. No big heavy people on her (really, it’s only been me and the trainer who started her), no allowing her to go inverted, lots of gently hill work, LOTS of stretchy walk work, bending and suppling work. Her loin connection is smooth and strong.
She gets bodywork and massages as necessary, and I do TTouch exercises and some of the Masterson bodywork.
She does have a long stride for such a small horse!, and has a comfortable trot; the challenge with her is straightness - long back AND being green - as well as getting her connected back to front.
She “steps” over small jumps, and has a powerful spring to her jump; spreads are a non-issue. She will have a TON of jumping scope, and finds it all very easy; IME, if you have a long-backed horse who is correctly conformed elsewhere, it is an advantage OF. The other long-backed horse I owned was a Saddlebred/TB (when I was a teenager in Pony Club), and he could jump the moon. We always joked that “it took him forever to come out of the stall” :lol:, and he was built sort of like a tube (as is my mare), so there were the inevitable train jokes. CHOO CHOO! My husband makes fun of my mare, Hahaha, yeah, honey, very amusing :rolleyes:
Anyway, I agree with all the above posters in that “it depends”! Some short-coupled horses have tremendous jumping scope, and are like rubber balls over fences! They are certainly easier to “put together”, but OTOH they can hold tension in their backs and lock the topline against you; lots of lateral work to free up the ribcage is helpful.
Interesting topic!