Poor seated posture leads to a forward head position. The more forward your head sits in relation to your shoulders, the ‘heavier’ it becomes in terms of pressure placed on your back.
Sitting tightens the hamstrings. When you sit, the knees are bent which causes the hamstrings to become shortened. When the hamstring muscles are shortened they pull the pelvis backwards (posterior rotation), which flattens the lumbar curve of the spine. This is a major cause of lower back pain.
Muscles that are constantly in a shortened state become tight. Tight hamstring muscles will affect your hips, lower back and pelvis. Without flexible hamstring muscles, our bodies must rely on other muscles to do their work, such as those of our lower back, buttocks and hips, overtaxing them and leaving them tired and more susceptible to injury.
Sitting also causes the hip flexor muscles to tighten, namely the iliopsoas, a two headed muscle which runs from the inside of our lower spine and the top of our pelvis down to the upper portions of our femur bone. When you sit all day the iliopsoas is held in a shorted position and slowly adapts over the years causing your pelvis to tilt forward (anterior rotation) placing excess pressure on your lower back.
The shortening of the hip flexors and the hamstrings tilt the pelvis in different directions. While you may think this is a good thing because they will balance each other out, it’s not. As the hamstrings and the iliopsoas fight each other they both get tighter and tighter. This reduces the range of motion of your pelvis and locks it into place, often far from a healthy "neutral" pose. It is a vicious cycle that makes it increasingly difficult to achieve a healthy alignment.
Tomorrow we will discuss the importance of breaks and how they can greatly help to reduce pain and the risk of injury. Make sure you don't miss it!