I think one of the easiest things to understand, but hardest to master is the correct sitting posture. A majority of the population tends to hyperextend their back and stick out their chest when we say “sit upright, good posture”. But is this the correct way to actually sit? Does it even feel comfortable? In this article we will address the ergonomics of sitting and advise on how to correct posture.
Anatomy of a chair
The foundation has to be addressed first before the anatomy of the human can be. If you have ever searched for a computer chair you probably came across multiple types including: flexible, curved, rigid, cushioned. To find the chair that fits you perfectly, they’re multiple factors that need to be addressed. The chair should support the curve of your back and allows for adjustable height. Your feet should be placed flat on the floor, with the computer monitor at or slightly below eye level. The chair should be flexible, but not enough to increase chance for poor posture. Remember the normal curvature of the spine is lordotic, kyphotic, lordotic. In my experience I have found a majority of the chairs do not support a thoracic kyphotic curvature. This places strain on other aspects the spine, increasing the likelihood for back and neck pain.
Ergonomics in the chair
Each part the human body has to be addressed with a functional outlook. Lets start with the cervical spine. The most amount of stress is on the transitional segments (C7-T1). A slight chin tuck allows to decrease strain of the cervical muscular, while maintaining the lordortic curvature. Scapulae should be slightly retracted and shoulders should be slightly depressed.
The thoracic spine has a natural kyphotic curvature. The chair should have a slight concavity to support the thoracic spine. I always tell patients to hyperextend their spine then flex there spine and then find a neutral position. This allows for the patient to find there own center of gravity, since each curvature is slightly different.
Lumbar spine has a natural lordotic curvature. usually if the first two curvature are maintained the body tends to position the lumbar spine into the appropriate position. Similar to the concept of the functional scoliosis. If there is an issue somewhere within the body, the body tends to compensate somewhere. Some pointers involve moving to the edge of the chair, placing feet on the floor. If your feet can not reached the floor either lower the chair or place a box under your feet. As in the slight concavity to support your thoracic spine, the lower portion of the chair should has a slight convexity to support the lumbar spine.
Your monitor should be at or directly below eye level. Your computer mouse and keyboard should be in a position that limits wrist extension, and allows for slight elbow flexion.
Upper and Lower Cross Syndrome
As a side note, upper and lower cross syndrome should be addressed. Correct posture should eventually be comfortable for the patient, as long as the strengthening and stretching of the upper and lower musculature is addressed. Search upper and lower cross syndrome to familiarize yourself with the pattern of tightness and weakness that is common is a majority of desk workers.