Not many people have strong healthy spines any more. I call them spineless not to attack their character but because their spines do not lock to their pelvis and seem to move quite independent of the pelvis and hips. Their spines are kind of loopy, slumped, and lack that elegant curve of proper lordosis.
Endurance athletes are very prone to spine pathology or pain. More than 40% of bicyclists complain of neck problems and a bit more have weak and sore lower backs. They carry their pelvis at a forward tilt, as do long-distance runners. (As an aside, nearly half of all bicyclists have sore knees. And many of the male elite riders have compressed vasculature in the place where you don't want to have it.)
A lot of spinal disfunction is from poor posture, though this does not necessarily lead to a perception of pain in all subjects. Again, bicyclists tend to compress the forward portion of the disks of their spine from long periods of flexion. The disks are elastic and material flows from the point of pressure at the front to the rear. Eventually, the spine can take a "set" in this direction and cause a stooped forward look to dedicated bicyclists, who also have necks that go the other way through the same forces acting at the rear of the cervical disks from keeping their head up. Poor bicyclists. A sad group really. I should write a Top Ten Reasons Not to Be a Long-Distance Cyclist some day.
But, much of the problem is that our sports and our exercises cause more spinal problems than they solve. And this brings me to the point...