Take a seat and don't be spineless

Innovative ergonomic seating launched to take pressure off laboratory workers

Chairs were originally designed to raise those with power above their inferiors. They provided an authoritative posture with a straight back, head and neck held in dignified stiffness, knees hips and elbows at a tidy 90 degrees. Chairs were not designed to be used for seated work. The industrial revolution made it commonplace to work long hours sitting in these same sort of chairs stressing the spine, producing musculo-skeletal pathologies and we are still using this basic antiquated design today.

New research published in the International Journal of Therapy and Rehabilitation found that pelvic posture and upper limb performance are intrinsically linked, proving the importance of the seating position for laboratory workers. Subjects performed a simple hand/eye co-ordination task whilst seating in two positions - firstly, in a standard flat-seated position and secondly, in the Bambach Saddle Seat. Interestingly, the results showed that when the participants were sitting in an auterior (forward) pelvic tilt position in the Saddle Seat, the error and task time were both significantly decreased.

Says Jill Ramsey, lecturer in physiotherapy at the University of Birmingham who supervised the study: “These days, many activities using the arms and hands are performed in a seated position. However, if the seat rotates your pelvis in the wrong direction as most seats do then back pain, reduced upper limb control, and diminished dexterity may result. Our aim was to identify what effect the position of the pelvis has on upper limb function, and we found that indeed seating, and the position a seat places your pelvis, has a significant effect. The subjects, when seated on a Bambach performed significantly better in upper limb tasks than the subject when seated in an ordinary position.”

Pelvic tilt - the heart of the matter
The human spine has a natural S curve which is automatically flattened the minute we sit in a conventional chair. Conventional seated posture, with thighs and knees at a 90 degrees angle, causes the pelvis to rotate backwards, replacing the natural spinal S curve with a kyphotic C curve. This compresses the lumbar vertebrae anteriorly, putting pressure on the spinal discs, which may in time prolapse. A certain result is a position of great postural stress. Pelvic tilt, although not externally obvious, is at the heart of the matter. Pelvic rotation affects all upper body structures and has often been missed by those treating pathologists of the wrist, neck, shoulders and back.

The underlying cause, pelvic tilt, remains overlooked.

Conventional workplace furniture
Attempts to alleviate the problems created by conventional workplace furniture almost always involve the introduction of corrective add-ons such as backrests with lumbar rolls or cushions designed to correct every human postural aberration. The fundamental design flaw which produces backward pelvic rotation and flattening of the lumbar spinal curve is again overlooked.

The solution is to totally re-think furniture design, allow for adjustability of work surfaces and for seating designed to prevent postural deformity.

A practical solution
To keep the upper body in its best functional position of least postural stress, it is ideal to keep the spine as close to its resting position neutral position as possible. This can only be achieved if the pelvis is in its upright neutral position.

The Bambach Saddle Seat is based on this principle. It allows for maximum skeletal stability of major joints (especially the pelvis and spine), in their neutral positions which maximises task performance while dramatically reducing stress on the upper body and spine.

It could then be said that one can simply ‘sit up straight’. This is possible for only a short period, because maintaining a ‘sit up straight’ posture requires too much muscular effort to be sustained for more than a short time. So to maintain the natural pelvic/spinal position (lumbosacral rhythm) the pelvis must be supported and be stable in its neutral position with the pelvis upright, the spine will be in its natural S curves. This requirement must be designed into the work seat. 
                                                                The saddle seat allows upright seating

The poor positioning of laboratory workers
Of great importance especially for laboratory workers, is the fact that the head and neck are adversely affected by poor positioning resulting from conventional work seats. Lumbar lordosis is automatically lost as soon as the thighs pass through 60 degrees flexion to reach the 90 degrees flexion required in conventional seating and we then see the familiar collapsed or “C” shape. The head is rolled back, the chin protruding and the neck hyper extended.

The ideal seat is one that:
• Preserves the natural “S“ curvature of the spine by securing the pelvis in its upright position even when leaning forward over instruments.
• Allows for excellent eye-hand co-ordination
• Good balance with a wide base of support
• Free movement of limbs
• Free movement around the surgery
• Allows maximum lung space.
• Allows maximum abdominal space. This can only be achieved by a straddle or saddle position. In this position the pelvis and spine are upright and stable in their neutral alignment

                                 Correct upright posture                Wrong posture can cause back pain


Adapting to your working environment
Seating for a healthy working posture needs to allow you to change the orientation of your body in space easily. You must be able to use your hands with sustained accuracy and freedom. The upper body must be free to move supported by legs and feet so that movement around the workstation is made by using the feet not propping, pulling and pushing with your hands. Postural muscles must be active and in balance. The relation of hip joint to pelvis and therefore to lumbar spine greatly affects the ability of the pelvis to remain stable in the upright neutral position it assumes in the Bambach Saddle Seat. This special design seats you in hip abduction hip external rotation and extension. This position opens the upper body to upright sitting, the hip joint in its resting position of least stress supporting the pelvis. The Bambach Saddle Seat provides a fundamental difference for us between active and passive sitting. To keep your pelvis upright on a conventional seat requires great effort which is not sustainable for long.

The Bambach Saddle Seat places the pelvis in its upright position and secures it there without the need for undue muscular effort.
This position does not require over reliance on the para spinal muscles alone. In conventional seating, deep postural muscles are dormant but in the Bambach Saddle Seat, they are engaged.
The difference is the result of design based on practical experimentation and research.

By Mary Gale, occupational therapist and designer of the Bambach Saddle Seat.
The idea for the Bambach Saddle Seat came to occupational therapist and horsewoman Mary Gale in treating patients who could not sit unsupported on an ordinary seat or wheelchair. Mary found that the same patients could balance quite independently on horseback and assume a symmetrical position.

It occurred to Mary that if she could replicate the saddle position, where the spine is able to assume its natural curves, she would create an ideal seat for therapy as well as for task seating.

A review of literature showed work of Dr A. C. Mandel, who noted that the ideal sitting posture for the human spine is achieved on horseback. Other researchers also concluded that ordinary furniture removes the natural curves from the spine and places great stress on the spinal discs. Anecdotal reports from horse riders who suffered severe back pain on the ground, yet who gained marked relief when mounted in the saddle, were also noted.

References
ADAMS,M:BOGDUCK,N:BURTON,K:DOLANP. Elsevier Science Ltd. 2002. The Biomechanics of Back Pain

CAILLIET,RENEM. D. F.A Davis Co USA 1984. Understand your Backache - A Guide to Prevention, Treatment and Relief

DAVISCOU. S. A. 1984 CARLSOOS How Man Moves

LONDON,HEINEMANN1972 CRANZ,GALEN The Chair

NORTONN. Y. 1998 FITZGERALD.C. P The Origin of the Chair in China

ANU CANBERRA. THECRESSETPRESSLONDON1965 FITZGERALD,C. P The Origin of the Chair in China.

ANU CANBERRA. THECRESSETPRESSLONDON1965 GRANDJEAN,E. Fitting the Task to the Man - an Ergonomic Approach

TAYLOR& FRANCISU. K. 1980 KAPANDJI J. A The Physiology of the Joints Vol 3 - The Trunk and the Vertebral Column