There is a large body of research and background, on spinal bio-mechanics, which you may wish to explore. This is important for an understanding of the principles for ergonomic remediation.
- A technical ‘fix’ is required if the increase in spinal morbidity, and cost to industry of absenteeism and stress due to LBP is to be halted.
- At present most work chairs can be unkindly designated as ‘Machines for making Backache’.
- Pressure studies of spinal loading show that upright sitting itself is seriously adverse. The mid-upright mode also carries other marked defects which are accentuated if the 90° hip angle (seat parallel to floor) or lumbar (as opposed to iliac) support is incorporated. ☛Pelvic v. lumbar support→.
- Recent scientific work on spinal pathology and biomechanics show that these ‘correct’ details are seriously adverse to spinal well being. Adverse effects of ☛mid-upright seating→.
- It continues to be accepted as ‘correct’. ☛mid-upright seating→.
- The mid-upright position details seem to have been codified in the 1920s as a result of a false premise (see Mandal. AC., The Seated Man (Homo sedens).1985. Dafnia Publications, ☛ Homo sedens→)
- Low Lumbar Backache (LBP) results in personal morbidity, loss of earnings and huge cost to industry. ☛ Prevalence and economic cost of LBP.
- Ergonomic chair design seems to have come to the end of the road with some, but not great, success in avoiding Low Lumbar Backache (LBP). A new ‘fix’ is in order and can be effected by the 2T concept. A ‘paradigm change’?
- The comment of Kenichi Ohmae (above) is apposite. ☛ Various chairs→
- You must not be misled by ‘comfort’, that treacherous guide which only turns up truthfully when the bio-mechanics (ergonomics) are fully correct. Comfort is improved the nearer a full remediation is approached. Full remediation = maximum comfort. See ☛ Comfort→
- The correct search should be for the Hippocratic “Do no harm”. Remediating the ergonomics is therefore essential. ☛ Remediation→
- It is hoped that this work may provide you with the anatomy and spinal biomechanics as a resource for the requirements for safe design.
- Bio-mechanic adverse designs can be avoided.
- It is most important to avoid →Familiarity bias.
- And →Normalcy Bias for your manufacturer.
Examples of ‘CORRECT’ There is now no excuse for poorly designed chairs and the conventional mis-advice that is perpetuated. It has to be said that these references, below, are to the back-rests of upright chairs and many of the tips are good,
Low Lumbar Backache (LBP). Some views.
All designers researched at a trade show expressed that their main object was based on a search for maximising ‘comfort’. Instead it should be ‘Do no harm’ based on correct medico-scientific research, as described here. See Comfort→. Forgive me for harping on this. It has occurred to me that, in spite of much good work, this misconception and familiarity bias may have held the chair industry back from a much needed sitting artefact. I hope that this will gradually come to be recognised.
The advantages of the unstable 2T (3M) transition mode are still not understood. The unstable TRANSITIONAL MODE. It’s importance.→
- The biomechanical imperatives show that a safe chair can easily be achieved with the ☛ ‘2 Tilt principle’→.
- You can try embarking on the more adventurous 2T or 4M desk-less work stations.
- The 4M workstation will be particularly relevant to the coming AI, VR & MR developments.
- Please do not hesitate to get in touch for queries, comments or more design details. Contact→
- At present (2015) designers have expressed worries that an innovative and supposedly ‘paradigm change’ expressed in the 2T concept excites negative familiarity bias. This is becoming less. and the concept is especially welcome with :-
- The ‘millenial’ post-graduate age group. It was noticeable how students at Cambridge loved the prototype and used it whenever possible.
- People who have Low Lumbar Backache. This large cohort, about 70% of the UK population, immediately see the advantages and ask “Where can I get this’. (Of course, they can’t!).
- Insurance is already begining to take an interest (personal communication). HAS
- Once people understand that it has health benefits, and possibly even more than any existing chairs, they will demand them.
- The offices of companies such as Google, Skype and Facebook, are like a playground with innovative furniture which would have looked outrageous ten years ago. This could include the 2T concept that I introduced in 1998. which is now no longer looking extraordinary.
- The TriModal (3M) or 2T CONCEPT is just that – a concept. It provides a designer with a practical basis for development of an ergonomically optimised office chair which can be achieved in a number of ways and styles.
Design details have emerged from work on prototypes and are available on request. The 2 TILT CONCEPT.
pMRI. Confirms assumptions derived from these bio-mechanical studies and clinical observation have been validated by pMRI scans (Smith FW,2007) which show that the reclined mode ensures migration of IVD nuclear material away from dangerous position near the back of the inter-vertebral joint which occurs with upright (90°) sitting. It is difficult to refute this evidence.
“Desks are rather a thing of the past – Dickensian even. They evolved as tables with storage developed, alongside chairs. The whole combination seems a way of reducing/avoiding the need for floor sitting or squatting and a means to provide a convenient standing/sitting presentation of objects for working with at an ergonomically higher level. They were there to support and present paper documents and the like. Hardware, since then, was largely developed to be used with/on them and has evolved through typewriters and similar devices to today’s electronics. Once that demand for physical documents has been reduced and even eliminated by ‘paperless’ office tech.”‘ (P. Bessey).
- 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, ☛ MANUFACTURE of ergonomic chairs → ☛effects of sitting→ ☛For Architects (Coolness is the word)→
- Office managers should consult this blog as a resource. It allows an alternative view to the usual hype from manufacturers, often laughably misguided. For further advice, see Office managers in MANUFACTURE of ergonomic chairs→
THE OFFICE OF THE FUTURE See→
With the advent of AI and robotics affices will be geared to the emotional and physiological requirements of the highly paid staff. 2 Tilt chairs and their 4M derivatives will be exactly relevant. But also see ☛ The end of sitting? →
Compared to people who sit the least, those who spend most time in a chair have a 112 % higher risk of developing diabetes, a 147% higher risk of suffering “cardiovascular events” such as strokes and a 49%t increased risk of death from any cause. (http://www.telegraph.co.uk/wellbeing/fitness/sitting-disease-is-killing-us-and-exercise-doesnt-help/) Alarming but not entirely an effect of the bio-mechanics and not examined here. However some posts are relevant. But also see ☛ The end of sitting? →
- OFFICE STRESS & Backache→
- ☛ Jukes. Managing the Ergonomics →
- ☛ PRODUCTIVITY AND WORKPLACE STRESSORS→ (Article published in EurOhs, European Occupational Health and Safety Journal, Dec 2002.by Dr HA Sanford)
- ☛ HAS, on ☛ Office health (& RSI)→ Only a lighthearted account.
- ☛The OFFICE 2 Tilt chair →
- ☛ 4M OFFICE WORK-STATION→
- ☛ SLEEP & productivity
The early concept depended on 2 positions, or modes, hence 2Tilt or ‘bimodal’ (2M). When I came to realise that the transition stage also carried benefits, if unstable, it became a mode in it’s own right. Hence the 2t became tri-modal (3M). If it can be adjusted to stop in mid-range it becomes effectively useless and is no longer a mode. Bias makes this concept difficult for most designers who have been taught to aim for infinite adjustability for comfort. A midrange position is, or is nearly, maximally ergonomically adverse and some users might mistakenly adopt it for prolonged work. Might they do this in the upright mode? Perhaps not as they have a more comfortable option with the reclined mode. Only time & experience will tell but that is why I have, pro tem, stipulated that this should have remediation built in, preferably a Forward Tilted Seat (Mandal) or pelvic support (Gorman). With a ‘deskless chair’ or workstation a 4th standing mode is incorporated and the concept becomes 4M.