( Originally Published 1930 )
To assume the correct sitting posture may seem a bit difficult at first, especially if old habits of sitting have twisted the body out of true alignment. When the correct posture is habitually employed one may work with much greater efficiency of body and with a minimum of fatigue, both physically and mentally.
EXERCISE 43.--Select a straight chair, one which is deep enough to accommodate the length of your thigh, and at the same time high enough to permit your feet to rest on the floor comfortably but not force your knees up.
(1) Sit as far at the back of the chair as you can, with the hips well up against the back of the chair—so far back that you feel almost as though you were going to sit on the back of the chair. This will serve to throw the emphasis of the weight of the entire body well forward upon the thigh muscles. The thigh is designed to do just such heavy work, having the longest bone and the largest muscles in the body.
Test your weight placement on the thighs by swinging the feet and by swaying the body in a circular motion from the hip joints. Keep the weight forward.
(2) Relax the spine completely. This will also tend to relax the arms, shoulders, chest and neck. Now relax the legs from the knee and the feet.
(3) Draw the abdominal muscles inward and up. This can only be done properly with a relaxed spinal column. Breathe naturally from the diaphragm, allowing the muscles to move up and down. This will retract the abdominal walls and lift the weight of the viscera from the spine. It will also serve to normalize any extreme hollow in the small of the back.
(4) Press back at the "hump" of the neck (c). This will lift the chest to an easy and normal position without strain, and will poise the head gracefully. Draw the chin in gently.
(5) Flatten the shoulder blades by a slight backward and down-ward pressure. Do this without rigidity or stiffness ; remain perfectly flexible.
(6) Feel as though you are drawn upward from the crown of your head and as though you are "sitting tall." Alignment is from the top of the head, thence through the hump of the back of the neck and down the spine.
(7) Be sure to tilt the body forward enough so that the tip of the coccyx rests on the seat of the chair, not bent under or resting on its curve.
Figure 33 illustrates a rigid, tense, and "erect" posture; unnatural and exhausting. The rigid spine, the forced lifting of the chest, the stiff neck and tensed muscles of the entire torso are not only use-less, but injurious. The weight is placed upon the coccyx and hip joints. This will cause undue pressure upon a delicate nerve plexus at the base of the spine, and tend to displace the hip bones. This posture is ugly and angular-it looks strained and anything but graceful. To attempt to hold a rigid posture, and at the same time hold the abdominal muscles up, makes breathing difficult and unnatural, especially if the spinal column is stiff and the breathing is abdominal.
Figure 34 illustrates the careless slump. This posture not only places the principal weight on a curved back, and the backs of the hips, but twists the sacrum and coccyx. It throws the entire spine out of alignment, prevents free circulation of the blood, impinges delicate nerves and inhibits the glandular functions. At the same time it displaces the vital organs ; cramping some, twisting others and bringing undue pressure where there should be perfect freedom. The neck and head suffer extensively from impaired nerve and blood circulation, which causes cell starvation, headache, nose and throat troubles, and affects the eyes very seriously. It also causes accumulations of fat about the abdomen, hips and shoulder blades. The brain becomes sluggish, the mind and memory clouded.