Ergomonics

In: Science

Submitted By janinelovesDJ
Words 4266
Pages 18
Theories of “Healthy” Standing
The “normal posture as recommended by Staffel and his 19th century contemporaries and has been promoted ever since by physicians, orthopedists, physical therapists, mothers, teachers, and military superior. Even today, that “upright” or “straight” standing posture with slight lordosis (forward bends) in the lumbar and cervical spines and a light kyphosis (backward bend) in the thoracic spine is stereotypically considered “good and proper” and is often called healthy, balanced, or neutral.
Theories of “Healthy” Sitting
Sitting Upright? Staffel recommended an erect posture of the trunk, neck and head, with normal slight lordoses in the lumbar and cervical areas and a light kyphosis in the thoracic spine, similar to the desired back posture when standing erect. The simple concept that sitting upright, with the thighs horizontal and the lowerlegs vertical, means “sitting healthily” endured for a surprisingly longtime.
Maintaining Lumbar Lordosis When one sits down on a hard, flat, surfaces, without a backrest, the ischial tuberosities ( inferior protuberances of the pelvic bones) act as fulca around which the pelvic girdle rotates under the weight of the upper body. Since the bones of the pelvic girdle are linked by connective tissue to the thighs and lower trunk, rotation of the pelvis affects the posture of the lower spinal column, particularly the lumbar region.

If the rotation of the pelvis is rearward, the normal lordosis of the lumbar spine is flattened.

Inclined surface Flat surface
Given the tissue connections between the pelvis an thigh-particularly the effects of muscles spanning the hip joint or even both the knee and the hip joints , the actual hip and knee angles are also affect the location of the pelvis and hence the curvature of the lumbar…...

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