One of our club sponsors is a physical therapy practice. A few times each year, we have our meetings at their business. One of the PT gives a talk and answers questions. Backs and knees are number one on the list and many of our members go to them for treatment. From what I gather, the problem with cycling is the back is in flexion which causes the discs to be compressed in the front and bulge in the back. This goes on for some time until the bulging disc impinges on a nerve. This is a totally simplistic example but is representative for cyclists.

The prevention, if there is any, is to get more pelvic rotation to create a neutral spine. This requires greater hamstring flexibility. One can raise the handlebars but that is too problematic as it shifts the forces to the quads and then the knees. Simple extension each day such as lying on the stomach and propping up on elbows will put pressure on the discs in the other direction. Strong lower internal core muscles (not easily developed) help immensely. Strong stomach muscles from crunching are not necessarily helpful.

They like the Roman Chair a lot but the standard is very tough. The gold standard in the roman chair for an isometric hold in a neutral spine position is 5 minutes without rest. The threshold for benefit is 45 seconds.

The other very good exercise group are bridges laying on the back and bridging to the shoulders. I do a lot of these.

YMMV a lot when it comes to backs.