Hi, Nate,all string players have bad backs. Regardless of whether it be violin, cello, guitar or doublebass. You spend so many hours in an asymetric position, what chance have you really got? Like mbhaub says, that is what technique and fundamentals are all about, really. Its how you manage all that strain by putting your body in the best position so your body doesn't break down and give out on you.
But that's not all the dangers. In my life, I've known alot of upright bass players. Most of them have injured thier backs loading the damn thing up after the gig, nevermind all the hours spent in asymetrical positions
anyway, I've never met a string player that didn't have a bad back or neck.
After 30 years of playing classical guitar with a traditional footstool, I developed back problems about two months ago that were seriously affecting my playing and comfort level. I switched to a Dynarette cushion* and the pain went away. However, it takes a real adjustment to play with two feet firmly on the ground after all those years using a footstool which results in a slightly higher posture for the guitar. However, the higher position has been a real benefit resulting in greater apparent finger strength and a cleaner more perpendicular approach to the fingerboard/strings for chord voicings and working in the upper register.
Dynarette Guitar Support Cushion, XL 5 inches
Strings By Mail
https://www.stringsbymail.com › ... › Guitar Supports