Along the lines of the cockeyed.com experiments, these folks decided to test the limits of what the US Postal Service would deliver. And now, the Annals of Improbable Research presents HOT AIR: Postal Experiments.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.