Principles of Posture
Your mother was right when she told you to stand and sit up straight. Not only does proper posture help you appear healthier than a slouching frame, but also promotes better musculoskeletal and organ function. Try this: slouch forward and attempt to take a deep breath. Now, sit up straight and do the same. You will surely find that breathing is easier with a proper posture. If breathing can be so influenced by posture, one can only imagine how other organ functions are affected. Also, improper posture excessively stretches [strains] or compresses joints and can lead to premature degenerative arthritis. The early symptom expression of excessive joint or soft tissue strain includes stiffness and aching pain after an activity or sustained posture, such as working on the computer.
When viewed from behind, the base of the skull, shoulders and hips should be horizontally level and the center of the skull should align with the center of the pelvis. From the side, a vertical line [plumb line] should bisect the ear canal, shoulder, hip, knee and side of the ankle. When seated, the horizontal and upper body plumb line alignments should remain unchanged.
Patterns of Use and Abuse
Neck and back pain sufferers commonly demonstrate predictable patterns of muscle imbalance. Some muscles tend to become excessively tight and overpowering, whereas others become weak and elongated. Subtle muscle imbalances may result in excessive joint and muscle strain, predisposing one to acute or repetitive strain injury. Tight/overpowering muscles require stretching, whereas weak/elongated muscles require strengthening. The foundation of spinal health is stable postural control and normal neutral alignment.
Effects of Poor Posture
A straight spine lacks optimal shock absorption and render the intervertebral discs vulnerable to injury. On the other hand, excessive spinal curves tend to over compress or stretch the more posterior spinal joints, known as facet joints. In either case, the supportive spinal muscles must work excessively to maintain an upright position and may result in muscle fatigue and pain.