An account of the bio-mechanic (ergonomic) factors, associated with prolonged sitting,  accounting for mechanical spinal pathology (Backache, LBP, IVDisc pathology, CTD) and options for their remediation for Sitting safely.

Screen Shot 2018-12-03 at 17.22.12Correct ergonomics are the essential and  fundamental requirements for any chair design.   This is obvious to any of the 70% of the population liable to backache.   Comfort may be essential for the other 30% but comfort depends on ergonomics.  

  •  The work is  intended as a resource for the designers of ergonomic work chairs.  It also represents some essential reading  for manufacturers of retail office chairs  if they wish to improve the ‘ergonomics’ of their models with overwhelming health selling points.
  • To avoid designing ergonomic adverse chairs.  Designers seem to have difficulties with the science behind ergonomics judging by the surprising number of poor chairs in the market.  ☛ Why?
  • Screen Shot 2018-07-08 at 16.30.31Most work-chairs are upright and only susceptable to partial remediations of the adverse effects of  The upright seated posture. →
  • To fully understand this work some knowledge of spinal anatomy, pathology & bio-mechanics is needed.☛  The SCIENCE
  •  Whether partial or full the basic ergonomic requirements for chair design for Sitting safely is described under ☛REMEDIATION →
  • The fully optimised concept involves a reclined work-mode and is the ☛The 2Tilt concept, the ultimate remediation →
  • It is also very relevant to Interior designers and architects involved with office design and not forgetting the ‘end user’ who has the ultimate benefit .

An overview of this work

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For an overview of contents…..

Screen Shot 2016-05-16 at 18.50.05See the SPECIALIST page →  This includes a large body of research and background, on spinal bio-mechanics.  It is subdivided into :-

Screen Shot 2016-05-17 at 15.59.14 Manufacturers can be reassured that feasibility indicates that existing components can be used , avoiding the expense of retooling, while preserving their brand image.   Prospective manufacturers can be helped to leap ahead of the field,    New ideas can create both threats and opportunities , once both familiarity  and normalcy biases are overcome.  Creative disruption works.

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to architects

For New offices ‘Coolness’ is the word to  excite media interest for both the company and the Architect/Designer.   Most firms aspire to project this cutting edge image.    A 2T chair, or the derived 4M workstation, answers this exactly and in addition reduces LBP and increases productivity by lessened morbidity and stress. ( Also see  ☛ Ergonomics and office stress.→ )

To office managersOffice managers should consult this blog as a resource.   It allows an alternative view to the usual hype, often laughably misguided, from manufacturers,


To remediationBackache & chairs.   A number of systems are described.  Spinal bio-mechanics dictates that prolonged Sitting safely should be performed in a reclined position with frequent change of posture.  For a full remediation  a number of requirements are essential.   To be effective these are detailed in the 2 Tilt (2T) concept.

Science,  and some relevant topics

  • Spinal anatomy includes a number of detailed studies of the more relevant component parts and an account of the paleoanthropology which resulted in the vulnerability of the lumbo-sacral junction.  ☛ Spinal Anatomy→
  • Biomechanics in relation to sitting postures.   ☛ Spinal biomechanics→.
  • How did we arrive here? ☛ Paleo Anthropology →
  • In addition,The way we sit now, further explores present sitting including the comments (☛Why? Mandal explains…→), Gorman and others.  Comparisons are made with various existing chairs  (☛How do they measure up?→).

  • 2T direction

    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.  

    Combining these requirements can be difficult to achieve but is possible in a suitably supported reclined mode at 40-45° which conforms to spinal morphology (configuration). This alone is impractical as a work position unless a number of secondary requirements are incorporated to make this simple concept suitable and practical for sitting safely in a work chair.

    1. A Screen Shot 2018-07-04 at 14.29.10 reclined mode which has a correctly supported, supine, stable position  for prolonged work    ☛2T reclined mode→
    2. An upright mode required for certain jobs.    ☛2T Upright mode→
    3. An unstable intermediate mode to enable a quick, easy transition between the 2T modes.    ☛2T transition mode→     With the recognition that the transition movement has physiological advantages, this has been upgraded to a ‘mode’.  dynamic seating→.   With the recognition that the transition movement has physiological advantages, this has been upgraded to a ‘mode’.  The 2T now becomes a triple-mode (3M) concept.

    These 3 modes constitute the basis of the 2T CONCEPT .

    A sit/stand facility can be incorporated to become a 4M version.    ☛SIT/STAND (& stools)

  • The office environment  it’s relation to physiological and psycho-social stress, ergonomics and remediation.
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