Originally Posted by
seypat
Now hinge at the hips and lower yourself into what would be a riding position keeping your back straight.
All good advice. If the OP is anything like me, he'll find that super tight hamstrings (and other overly tight muscles and ligaments) keep him from hinging at the hip and cause an arched lower back.
I only recently started a daily stretching routine to try and get back to a straight back. Decades of biking w/o stretching and office work has not been kind to my flexibility!