One of the best pieces of advice I got in Chiropractic School was at a seminar about the foot. Ironically, it had nothing to do with feet. He said, "Get good at mobilizing and stabilizing the spine transitions."
What he meant was in the neck or cervical spine you have a lordosis. The midback or thoracic spine has a kyphosis. The lowback or lumbar spine has a lordosis. Your sacrum has a kyphotic curve. The junctions are referred to as C/T junction, T/L junction, and L/S junction. All require certain amounts of movement and stability.
What I had been doing for the T/L (thoracolumbar junction) was to adjust the specific segment that needed more motion. Check the Psoas at the attachments as it can attach all the way up to T12 and work a little with the diaphragm. While this worked and would resolve issues, I found that it wouldn't last as long as I would have liked, especially with cyclists.
That extra kyphotic position of being on the cycle really stressed that T/L junction. What I gleaned off a Stuart McGill talk was really target their Lat strength. It really seems to work.
The Latissimus Dorsi has origins from T7-L5 and all into the sacrum facially, then insert into the humerus. Having patients and athletes incorporate some direct Lat work through chin ups has kept the T/L junction in alignment and working well.
If you work with clients that have this problem, give this a shot. If you know your T/L junction locks up and gets out of alignment, try a series of chin ups a few times a week and see if this helps correct it. I believe it will.