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It is hoped that this may provide a resource for designers and users of work chairs.  There is a large body of research and background, on spinal bio-mechanics, which you may wish to explore.

OBJECT. To identify and address  the adverse bio-mechanic (ergonomic)  factors that  potentially were liable to result in spinal component break down which can account for Low Back Pain (LBP, backache and more serious disorders, IDD, CTD.)  in relation to the seated posture, 

METHOD.   Existing work on spinal pathology and biomechanics related to upright seated posture  was  explored.

CONCLUSION.  The evidence identified adverse effects which occur with conventional prolonged mid-upright sitting that required remediation.   It was found that a reclined mode is the only position that avoids all the adverse effects of prolonged upright sitting.  This conclusion became validated  by independent work using pMRI scanning (Smith 2007)  


The 2 TILT  chair CONCEPT.

The big story here, however, is that it was found that a reclined mode is the only position that avoids all the adverse effects of prolonged upright sitting.    For a reclined office work-chair to be practical a number of requirements are essential.  These have been covered in the 2Tilt concept which was tested for practicality in the Cambridge MfI department.

Screen Shot 2016-03-18 at 19.28.20The 2T concept addresses all the ergonomic factors  that  ensure a sitting position that is the least likely to perpetuate, or result in, backache and other spinal conditions. It also includes the necessary requirements to make this a user-friendly practical work-chair.  Comfort → is also thereby maximised.
The 2T concept is fully described by following  ☛A Full solution→
Briefly it involves :-

1 A Reclined mode

  • sitting safely reclined modeA fully body support reclined mode, configured to the correct spinal  shape. is optimal for prolonged work.  ☛The 2T reclined mode→
  • The reclined mode requires head support that allows for a forward vision field.
  • Variability at head and feet only.  Avoided elsewhere. Adjustments→.

2.sitting safely upright mode  An  Upright Mode (eg. forward tilted seat,) is subsidiary but  required for certain short activities and quitting the chair and is the default mode when the chair is unoccupied.  ☛2T Upright modes→

3. Screen Shot 2015-10-07 at 13.43.22The mid ranges should be unstable and easily negotiated    ☛Unstable intermediate mode →.  This is to avoid  the conventional adverse mid-upright sitting posture.  It can be used for short periods as a form of exercise ( ☛ dynamic seating→), particularly for rehabilitation  following an acute attack of Backache.

4. This leads on to the QuadriModal 4M work-station→.

The 2T concept is fully described by following  ☛A Full solution→


The menu on the right→ indicates the layout and lists more posts than the main top menu.     Next  ☛  How to use this work →

Managing the Ergonomics of Office Seating

 by John Jukes                  The Source Publishing Company Limited 

Ergonomics expert John Jukes asks is the Sit/Stand desk the answer to aches and pains in the office?

Research done by Dr Henry Sanford, Orthopaedic Consultant at the Cromwell Hospital, adds another dimension to the problem of ergonomic comfort in the office. Sitting in a semi reclined position at 45 degrees reduces the gravitational loading on the spine by 50%. This is similar to the astronaut position, which permits working under heavy G forces. A suitable headrest and positioning of keyboard and VDU screen makes this a perfectly practical working position without inducing sleep. Many programmers, CAD users, control room engineers and tall people are seen to adopt this position using an ordinary chair when  working for long periods – perching the tail on the front edge of the chair with their shoulder on the back and the legs out straight.

Sit/stand desks and pelvic support semi recline seating  in the UK have yet to become part of the normal office landscape. When they do there will be several million office workers that will be grateful to be free from daily debilitating pain.

He wrote

HAS & M19.08.43Dr Henry Sanford MA. MB. B Chir. (Cantab) D  Phys Med. (Lond) is a well known Consultant Orthopaedic Physician in London and Associate Consultant to the Department of Rheumatology, St Thomas’s Hospital, SE1.  Earlier he worked at St Thomas’s with Dr J H Cyriax who is regarded as the ‘Father’ of  Orthopaedic (or Musculo-skeletal) Medicine after following 2 years in the army finishing as a Captain in the RAMC.

He was a founder member of the Society of Orthopaedic Medicine (SOM), the British Society of Musculo-skeletal Medicine (BIMM) and was Chairman of the Cyriax Organisation..  He has run courses and lectured internationally                                                              John Jukes – 30/07/2001     Site Navigation→