Do you trackies do a lot of stretching? Because besides intervals and varied training, it seems that the one thing I hear over and over is that you need to stretch a lot and be as flexible as possible. The lower back seems to be an overlooked area. Calves and hamstrings are important, and they all tie into the lower back. Of course, you need to balance that with strong abs. You may not need the ab strength for cycling, but you need to balance your torso front to back.
Jock will back me up on this one - there's value to be gained just listening to any advice Rob has to offer. Perhaps one day I will put it to good use.