I posted here many months ago that i was experiencing incredible pain on my left hand's thumb that caused me to be unable to play for more than five min. I was taking lessons from a simandl teacher who was a fine player no doubt, but could not address my problem and basically told me "I just need to get in shape". This past January I started taking lessons in Charleston SC with the jazz bass professor at the College of Charleston. As soon as I started playing he immediately recognized about 5 problems with my technique. 1. Clamping down and keeping my fingers pinned to the fingerboard the entire time, allowing no freedom of movement. 2. Using my hand muscles instead of my back muscles to press down the string. 3. Curling my wrist to an uncomfortably odd angle in order to play on the E string To solve these problems he had me start playing sitting down with my right leg standing and my left leg hooked on the stool. The bass row rests on my leg. I the bass back now, with my leg serving as the anchor preventing it from hitting the ground. Instead of curling my wrist I keep my hand straight and curl my fingers to play on the lower strings, moving my hand closer to the finger board if needed. I also keep all of my fingers free using only the finger I need to play the specific note. I shift as opposed to stretching. I have small hands so I even shift a bit when moving from Bb to C in first position. I cannot tell you what a difference this has made for me. I never experience pain anymore, I am able to play as long as I want, and the bass has actually become fun, as opposed to a painful chore. I have even applied this same method to my electric bass playing, with the emphasis being on shifting rather than stretching. I realize that everyone has a method that works for them so I am not touting this as being better than anything, all I know is that it has worked wonders for me and I am happy.