Originally Posted by
bikerjp
I'm the opposite. I found slightly less back pain when I stretch out and flatten my back. I had my stem lowered to get a more flatten position. When I scrunch I hurt more. Also think pushing higher gears adds to more back pain. I think it's the side muscles, not sure the technical name, that hurt and get stiff.
+1
Listen to bikerjp's advice. This is why many suffer needlessly from back pain. They do the opposite of what it takes to eliminate it...having poor posture on the bike. I also believe core strength is over played as a solution.
OP, you need to 'rotate your pelvis' forward. Think pressing your belly button to the top tube. If this puts too much pressure on your balls then change saddles and find one with a cutout. If you don't release your pelvis and flatten your back you are in for a long tough road. Riding hunchback, scrunched and upright on a road bike is not only slow but it pile drives your spine and sets you up for arm, neck, upper back and trap pain.
Your back hurts because you are over extending it by planting your sitbones rearward instead of rotating your pelvis forward. Many believe that the root of back pain is lack of flexibility but position trumps flexibility when it comes to pain.
Road bike position is really the opposite of what many believe and why so many struggle with it.
Hope that helps....the anatomy of what I describe is depicted below: