Posture is everything. Your body has to obey the laws of physics, and as such, the forces acting on your body position can alter and permanently deform your posture if left unchecked. Look around and you see it everywhere. Heads slumped forward, shoulders rounded and internally rotated, lumbar spines flexed forward, and hips tucked beneath us in a retroversion. Then, these same people make committment to improving their health and fitness by starting a strength training program, and hurt themselves. And even if they happen to escape injury immediately, their training performance and progress is thwarted by the inability to create a stable foundation underneath their exercises. So ultimately, your posture will determine you risk of injury, training progress, and exercise performance.
So if you are one of the many people around you who have poor standing and seated posture, here is some corrective exercises you can starting incorporating in your training. This video focuses on head, shoulder, and thoracic mobility. You need to bring the head up and back, drop the shoulders down and back, and extend the rib cage upward, while stretching the front of your shoulders and chest, and strengthening your upper back. A big part of this whole equation is preventing forward internal rotation of the shoulder in its socket. Enjoy the video and get started with corrective exercises.