In the depths of my back issues the chiropractor thought part of my problem had to do with the relative positioning of the left and right sides of my pelvis. The pelvis is not one solid piece, and the two sides can rotate with respect to each other. Every time I saw him he would note this and give me an adjustment.
Once I started feeling better and was developing a new exercise program for myself, I decided I wanted to incorporate some sprint work. I went to a soccer field to run 100 m sprints. I took a couple of warm-up laps, and then I hit the first all-out sprint. Here's where it gets strange. As I was running I felt this movement in my pelvis... a slip and then a catch between the two sides... like when you switch gears on a bicycle going up a hill. I thought, "God I hope I'm not screwing up my back". I continued the sprint session, and the next day my back felt... AWESOME!
So, what does this mean? I can't prove anything, but I wonder if there might be a self-corrective mechanism in sprinting. I talked with my chiropractor about it, and he alluded to the scene in Forrest Gump when, running for his life, Forrest shakes off the shackles of his leg braces - his body's attempt to re-establish its natural movement pattern. It makes sense from a survival perspective that our bodies would be able to correct imbalances through movement since there were no health practitioners in primal days. As for me, I'm not going to overthink it. I'm just gonna run with it.