Those of us who can heal through exercise are lucky. I would guess there are many with more difficult cases. I now know I am better stretched over a drop bar bike. My back went out when I started putting more time in on my wife's MTN bike. I admit that I did my own fit, for the shorter rides. But...the upright position, and fit, may have done me in! As a dentist, I am at high risk for back problems. Swimming during biking season is a must from now on.