Correct Posture Principle. Good posture is fundamental to proper development of body structure, especially of the bones and muscles. It aids the development of vital capacity and promotes deep breathing. It also encourages the circulation of blood to and from the heart. An erect bearing not only benefits physical health, but it lifts the spirits and promotes mental alertness and the dignity of self-possession.
Physical posture is often a reflection of mental attitude.
A stiff, military-like posture and a slouched or drooping posture are both unhealthful. The stiff, precise posture puts an unnatural strain on the muscles. A prolonged crouched or hunched position leaves the lungs with inadequate room to expand. It causes shallow breathing, reduces vital capacity and puts strain on the heart. It depresses and unbalances the circulation and contributes to headache, backache and aching neck, legs and feet.