The typical way you are told to fix your posture is to stand up straight, lift your head, and throw your shoulders back. Maintaining this position is very fatiguing. Another common way you are told to improve posture is to strengthen your back muscles and stretch your anterior chest and shoulder muscles. These approaches do not take into account the amazing power of the diaphragm to improve both mobility of the spine and strength of the trunk.
The diaphragm is a flat muscle that sits as a dome shape and lies in between your thoracic cavity and your abdominal cavity. When you inhale it lowers to make room for the oxygen entering our lungs. The lung expansion means your rib cage expands laterally, then when you exhale the rib cage narrows and the diaphragm returns to its resting position. This is called horizontal breathing. Did you know approximately 9 out of 10 people do not breathe horizontally, but vertically? Vertical breathing recruits your neck muscles for inhalation. These neck muscles, namely the scalenes and sternocleidomastoid, are supposed to be accessory breathing muscles not the most active ones. Learning to breathe with your diaphragm is the key to unlocking your postural tension. Watch my video for exercises combining breathwork and mobility.