Originally posted by karoly aczel
Yeah ok, just keep standing then.
All things are subject to the second law of thermodynamics.
That means all physical systems are subject to decay, right?
Nothing to do with the second law of thermodynamics Karoly.
When in a sitting position the muscles that flex the hip joint (think bringing your knee to your chest) are in a shortened position. As a result of being in a constant shortened position they become tight (they being namely
Iliacus and
Psoas). The tight hip flexors then pull the front of the pelvis down, it's sexy name is
'anterior pelvic tilt'. The front of the pelvis going down means the back (posterior) goes up, the back of the pelvis moving results in the spine moving, as the spine is connected to the pelvis. This creates lordosis in the lower back. Not good. Now muscles that anchor the spine to the pelvis (namely
Quadratus lumborum) are in a shortened state, and as a result they now become tight.
Add to this mix the glutes ie your ass. Being sat down all day means that the glute muscles are in a lengthed position, being in a constant lengthed postion has the opposite effect of being in a shortened position. They become weaker.
Your muscles work in what's called 'chains', to perform a movement, they have to work together. The most important chain is what's called the 'posterior chain', which basically mean your hamstrings, ass (of which there are lots of muscles), and your lower back. Now we all ready know that sitting down for long periods of time lengthens the glutes which makes them become weaker. That means the other muscles in the posterior chain have to take more of the work as the glutes aren't pulling their weight.
The lower back (ie
Quadratus lumborum which is part of ther posterior chain) is already tight from being in lordosis, now it has to work harder because the glutes aren't working properly. You end up with a tight shortened muscle working more then it should do. That creates pain. And that is the basic nuts and bolts of why 1/4 people will suffer from back pain at some point in in their life. Me being one of them.