Rani Lueder, Kageyu Noro, Steven Reinecke, Shunji Yamada ...The physician can deter mine this w ith...

Rethinking back support: Sacral, lumbar or "live backs": NECE / ErgoExpo 2007 workshop slides

Rani Lueder, Kageyu Noro, Steven Reinecke, Shunji Yamada, Cindy Burt 1

Rethinking back support…… Sacral, lumbar or “live backs”?

Rani Lueder (co-chair)Humanics ErgoSystems, Inc.

Encino, [email protected]

Kageyu Noro (chair)Professor Emeritus, Waseda UniversityChief Tech. Officer ErgoSeating Japan www.ergoseating.jp

Prof. Kageyu Noro (ErgoSeating / Waseda Univ.)

Rani Lueder, CPE (Humanics ErgoSystems, Inc)Steven Reinecke (Biomedical consultant)Shunji Yamada (ErgoSeating Co. Ltd)

Cindy Burt, OTR/L, CPE (UCLA Ergonomics Program)

Rethinking back support…… Sacral, lumbar or “live backs”?

• How do we think we sit?• How do we actually sit?• How should we sit?• What is the difference?• What really matters?

• Consulted and served as principal of Humanics ErgoSystems since 1982.

• Specialized in occupational ergonomics and ergonomics research and design of products and places for adults, children and people with disabilities.

• Edited and co-authored three books in ergonomics.

Rani Lueder, CIEE, CPE

If all you have is a hammer, .. . you think everything is a nail.

Creates its own reality



• Professor Emeritus, School of Human Sciences, Waseda University.

• CEO and CTO, ErgoSeating, Japan.

• Directed the University of Waseda’s prestigious Seating Research Laboratory for more than 20 years.

• Edited and co-authored fourteen books in ergonomics.

• Organized many conferences on seating and posture.

Prof. Kageyu Noro Zazen sitting

Research activities of …

• Seating Research Labs, Waseda University

• ErgoSeating (Applied research supported by Waseda University)

• Served as Vice-president and Chief Technical Officer of several medical device manufacturers for products that treat low back pain from surgical to non-invasive treatment modalities

• Over 20 US and international patents

• Prior to that, he conducted research at the Department of Orthopedics at the University of Vermont.

Steven Reinecke

Static PosturesResults In:

Local Muscle Fatigue

Strained Ligaments

Sta tic postures

• Technical Advisor to ErgoSeating in Japan.

• Served in an Executive Board Member of Toyo-Kogyo Industries, Inc.

• Received his MS in Engineering from Case Western Reserve.

Shunji Yamada, MS Eng. Zabutons

Adapted from: H. Oyama, T. Teraoka, K. Noro, “Development of Floor-Cushion with Pelvic Support (Ergo-zabuton),” Proc. of the Conf. WWDU2002 World Wide Works, Berchtesgaden, May 22-25, 2002



• Created and manages UCLA’s ergonomics program for their 27,000 employees

• Teaches ergonomics to Occupational Therapy students at the University of Southern California in Los Angeles.

• Previously managed the work injury rehabilitation program at UCLA’s Medical Center

Cindy Burt, OTR/L, CPE How do we really sit?

Thank you!

Prof. Kageyu NoroProfessor Emeritus, Waseda UniversityChief Tech. Officer ErgoSeating Japan www.ergoseating.jp

Rani Lueder, CPEHumanics ErgoSystems, Inc.

Encino, [email protected]

Rani Lueder, CPE Humanics ErgoSystems, [email protected] www.humanics-es.com

Rethinking back support…Sacral, lumbar or “live backs”?

Over 1,000 postures people can sustain

Hewes, G.W. (1957) The anthropology of posture. Scientific American. Feb. 123-132.

Our seats reflect our assumptions



Neutral spine

Keegan, J.J. (1953) Alterations of the lumbar curve related to posture and seating. Journal of Bone and Joint Surgery. 35A, 3, 589-603.

Neutral postures

Balance muscle loads Reduce physical demands Relieve physical stress

Intradiscal pressures

Andersson, B. J.; Ortengren, R.; Nachemson, A.; Elfstrom, G. (1974) Lumbar disc pressure and myoelectric back muscle activity during sitting. I. Studies on an experimental chair. Scand J Rehabil Med. 6(3), 104-114.

Intradiscal pressures

Wilke, H. J.; Neef, P.; Caimi, M.; Hoogland, T.; Claes, L. E. (1999) New in vivo measurements of pressures in the intervertebral disc in daily life. Spine. 24(8), 755-762.

Center of gravity of males & females.

Tichauer, E. R. (1978) Biomechanical basis of ergonomics: anatomy applied to the design of work situations. Wiley, John & Sons., 99.

Dunk, N. M.; Callaghan, J. P. (2005) Gender-based differences in postural responses to seated exposures. Clin Biomech (Bristol). 20(10), 1101-1110.

Dunk & Callaghan (2005)



“Rotatory”movements

van Deursen, D. L.; Lengsfeld, M.; Snijders, C. J.; Evers, J. J.; Goossens, R. H. (2000) Mechanical effects of continuous passive motion on the lumbar spine in seating. J Biomech. 33(6), 695-699.

As we shift posture, dynamics change

Graphic with permission from Corlett, E. N.; Eklund, J. A. (1984) How does a backrest work? Applied Ergonomics. 15, 2, 111-114.

Rani Lueder, CPEHumanics ErgoSystems, Inc.

[email protected]

Thank you!

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New research findings: The

impact of sacral and pelvic support

on the spine

Sacral support since the 13th century

Prof. Kageyu NoroWaseda [email protected]

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skeletonmuscles

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Zafu floats the spine

Contact Surface Zafu and Monk



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Standing0゜

Zen Sitting5゜

Chair Sitting24゜

Pelvic rotation

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Pelvic rotation determines the extent of lumbar lordosis

PelvicSacrum

Lumber lordosis:腰椎前弯 Kyphosis:後弯

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musclesbuttocks thigh

sacrum

comfort discomfort

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Advantages of sacral support1. Stops pelvic rotation2. Promotes muscular

contraction3. Reduces pressure on the

buttocks

Health and comfort

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Design guidelines for back supports

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Good

Bad

Pressure Distribution



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Comfort cup

A sample chair for the experiment (not for sale)

Comfort cup

38

Conventional The new concept model

Pressure distributionPeak value of pressurePelvic tilt angle

A new seat comfort concept:

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Upper back – postural support

when reclining

A sample chair for the experiment (not for sale)

Low back comfort…sacral andpelvic support

High Performance Seatpan (HPS) 40

Realization of premium comfort

Cradle

Zen Meditation

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Steven ReineckeSteven Reinecke

NECE2007: Rethinking Back Support:

Sacral, Lumbar, or “Live backs”?

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An Overview Of Low Back PainAn Overview Of Low Back Pain

Low back pain significantly Low back pain significantly affects 70affects 70--80% of adult 80% of adult populationpopulationMost frequent cause of lost work Most frequent cause of lost work days, after common cold, in days, after common cold, in persons under 45persons under 45Incidence same in sedentary Incidence same in sedentary individual. vs. those performing individual. vs. those performing heavy labor jobsheavy labor jobs



43

COST

LOW BACK PAIN: LOW BACK PAIN:

TIME

< 3 Months > 3 MonthsAcute LBP Chronic LBP

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COMFORT COMFORT ------ LOW BACK PAINLOW BACK PAIN

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Proper spinal curvature Proper spinal curvature

46

PosturePosture

KyphosisKyphosis3x (+) IDP3x (+) IDP

Lordosis Lordosis ((--) IDP) IDP

47

Poor Posture & Forward Flexion

The reaso n that poo r lumbar po sture increases the lik elihoo d of back pain is that when you flex fo rward o r sit with a k ypho tic po sture you cause the in tra-d iscal fluid to migrate po sterio rly while also stretching the po sterio r lig am ents .

48

Disc derangementDisc derangementNerve root entrapment/impingementNerve root entrapment/impingement

Mechanical DiagnosesMechanical Diagnoses



49

CT ScanCT ScanNerve root entrapment/impingementNerve root entrapment/impingement

The ph ys ic ian can d eter min e th is w ith a CT s can or M RI, wh er e you c an se e the intra-d is c al m ater ia l imping ing ag ainst the sp ina l cord.

50

This posture is also important beca us e i t affects th e load concentra ted on the spina l col umn. Think of your spine , upper body and bac k m uscl es as a see-sa w.

The spine or Vertebra is the ful crum poin t of the see-s aw , the upper body is one s ide, whi le the ba c k m uscl es are the other s ide. In order to bal ance , the res ul tan t force on both sides mus t b e e qual .

51

If you were to sit in a forward flex position, (as depicted in the top Free body diagram) you can see that the constant force of the upper body moves further away from the spine. In order for the body to balance, the back muscles increase in force to counteract this load

because the back muscles can not move further away from the fulcrum point. Unfortunately when the back muscle force increases, the resultant force on the spinal Disc increases greatly.

In order to keep the load low, you must maintain an upright posture. (as depicted in the bottom Free body diagram) UpUp--RightRight

Upright

52

What Feels Good What Feels Good is not always Goodis not always Good

53

Static PosturesResults In:

Local Muscle Fatigue

Strained Ligaments

We kno w that poo r po sture will cause, o ver tim e, either lo calized muscle fatigue OR strained spinal lig am ents. The best way to control these detrim ental effects is to chang e o nes po sture. By chang ing your po sture you will share the respo nsib ility o f suppo rting the back and give the previously lo aded muscles and lig am ent s tim e to reco ver.

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““Movement Heals HumansMovement Heals Humans””



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Spine is Designed for Activity Spine is Designed for Activity

Flexible Strength: Provides Primary Support & Mobility on many Planes

Structure: Houses and Protects Major Central Nerves

Complexity Makes Susceptible

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Nourishment Supply toDisc

Motion

Diffusion

The importance of motion is also critical for maintaining the nourishment supply to our discs.

There is very little blood flow within the disc. The intra-discal fluid gets its nourishment from diffusion of fluid in and out of the

disc. Many researchers have investigated the effects of spinalmotion on metabolic parameters of intra-discal fluid. They all suggest that the flow of nutrient rich fluids to and from the disc increases with spinal movement. Thereby recommending that

postural changes take place thru-out the day. ……..

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Functional Motion: Spinal region Functional Motion: Spinal region

CervicalThoracicLumbar

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Vertebral MotionVertebral Motion

FlexionLateral BendAxial RotationCoupled

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VertebraVertebra

BodyBody

Transverse ProcessTransverse ProcessLateral BendLateral Bend

Facet JointsFacet JointsRotation Rotation

Spinous ProcessSpinous ProcessFlexionFlexion

60

Anatomy of the VertebraAnatomy of the Vertebra

Similar but unique size, Similar but unique size, shape, angulation at shape, angulation at each leveleach levelVariations in structure Variations in structure effects functionalityeffects functionality



61

Biomechanics: Form and FunctionBiomechanics: Form and FunctionCervical Cervical (ROTATION, (ROTATION, FEXION) FEXION)

7 segments7 segmentsC1 (ring) pivots on C2 C1 (ring) pivots on C2

Thoracic Thoracic (STABILITY) (STABILITY) 12 segments12 segmentsVery little motionVery little motion

Lumbar Lumbar (WEIGHT BEARING, (WEIGHT BEARING, FLEXION/EXTENSION)FLEXION/EXTENSION)

5 segments 5 segments Weight bearingWeight bearingPaired facet joints allow Paired facet joints allow flexion/extension flexion/extension Very little rotationVery little rotation 62

As we lo ok at existing chairs mo st have a fix ed p lane back rest with little acco mmo dation fo r chang es in the shape o f the sp ine. They also do no t target the individual segm ents of the spine, in respo nse to their predefined range of m o tion .

As one flex es fo rward we see the g reatest chang e in curvature with in the lumbar reg ion and m inim al change in curvature with in the tho racic reg ion . In this case we o nly see the lo wer back being suppo rted . H o wever as a person reclines, the g reatest change in curvature will again o ccur with in the lum bar region and with th is change, the lo wer back becom es unsuppo rted .

What typ ically happens, is the perso n actually confo rm s to the chair, thereby, no t getting the benefits o f chang ing their spinalcurvature.

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To address this issue, backrests today provide a lumbar “cushion” which provide proper support in the reclined position. However these lumbar “cushions” will only provide minimal support for both the lower and upper back in the forward and upright position.

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So what should the future of seating include?Good support that provides load sharing of the upper and lower back thereby reducing the level of pressure within the intra-disc of the spine and transferring the load to the backrest’s secondary support system

A backrest which will provide the appropriate range of motion for each of the different regions of the spine. Flexion extension of the lumbar region with minimal change in curvature of the thoracic region. And finally, a chair that promotes motion during the course of the day, minimizing motionless postures. By allowing motion we’ll reduce the excessive strain to isolated muscles and ligaments. While also improving nourishment to the intra-vertebral disc.

The Ideal Seat!The Ideal Seat!

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Shunji YamadaErgoSeating Co., Ltd.

syamada[@wa2.so-net.ne.jpwww.ergoseating.jp

• Background• Previous research• Ergo-zabuton validation trials• Research conclusions

November 29, 2007

NECE2007: Rethinking Back Support ― Sacral, Lumbar, or “Live backs”?Zabutons: sacral and pelvic support

66Source: ErgoSeating’s in-house research (Kageyu Noro, 2007)

A variety of females’ sitting styles reflect Japanese seating culture



67

Cross-legged sitting (Agura)

Floor sitting postures such as cross-legged seating:

- Increase risk of musculoskeletal

disorders (e.g., low back pain)

- Tend to tilt the pelvis back

kyphosis


Problems with floor seating

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Pelvic support floor-cushion

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• To develop designs that support the sacrum and pelvis more effectively.

• To accommodate females’ common sitting postures (incl. cross-legged, split & side sitting)

• To meet functional criteria (e.g., compact, easy to carry)

A challenge to a renewed version

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1 Sacral / pelvic support

2 Ischial / buttocks support

3 Pommel

4 Three dimensional slope

5 Cushion: hard under buttocks, soft in front

Project design director: Dr. Kageyu Noro

35 cm

13 cm

37 cm

A sample only for experiment (not for sale)

Characteristics of the Ergo-zabuton

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Ergo-zabuton Zabuton Tatami Matt

25

20

15

10

5

0

Post

erio

r pel

vic

tilt (

deg)

Adapted from: S. Aizawa, “Research on development of body-supporting seating cushions,” Graduation Thesis 2006,Noro Lab. Waseda Univ., 2007

ErgoSeating patented pelvic tilt measurement system.

Tilt angles at the left represent averaged values from 14 subjects.

Data collection: Posterior pelvic tilt

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The combination of pommel and 3D slope promoted more effective seat pressure distributions

(a)

(b)

(a) With pommel and 3D slope

(b) Without them

Seat pressure distributions



73

The ErgoZabuton…

1. Promoted lumbar lordosis through reduced pelvic tilt.

2. More effectively distributed seat pressures (based on seat pressure distribution data)

3. Was rated more comfortable (seat trials, 54 subjects).

Thank you for your attention!

Research Conclusions

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Rethinking Back Support

USER PREFERENCES: ACTIVE VS FIXED SEATING

Cindy Burt, MS, OTR/L, CPE

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How we sit depends on…

What we need to do.

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How we do it.

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How well we can see.

78


How far we need to reach.



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How long we have to do it.

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There are lots of ways to sit…Dynamic sitting

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And then there’s…Passive sitting

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Dynamic Chairs

Active backActive back and seat

SynchronousNon-synchronous

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Active BackBack movesSeat pan locked

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Active BackBack changes shape



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Active Back and Seat

Synchronous: Seat and back move as unit

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Active Back and Seat

Non-synchronous: Back and seat move independently

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Active Seating

Non-traditional seatingBall chairSitting discSwopper chair

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Active Seating

Non-traditional seatingStokke Gravity chairRecliner

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Fixed Seating

Non-dynamic seating

CourtroomsSchools and lecture hallsRestaurants

Dynamic seating locked

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How we sit is determined by…

Our posture, culture and habits



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Our work demands

92


Our stability

www.healthline.com

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Workers Move in Space to Work

…with or without their chair

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They reach beyond limits of chair.

Workers prefer fixed backs when…

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They complete frequent bilateral hand tasks.


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They complete precise work.




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They are obese.


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Their workstation is too high.


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They have limited stability.


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They have back pain.


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They have poor sitting balance or control.


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They aren’t encouraged to move.




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They don’t know how to adjust their chair.


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Why Do We Want Back Support?

Decreased disc compressionSit upright longerImproved posture

From Corlett & Eklund (1984)How does a backrest work?Graphic with permission

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Supported Active Sitting

Chair Pelvic controlLumbar supportThoracic supportAdjustable seat pan length

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Chair Dynamic reclineSelf-adjusting mechanismUsabilityQuality

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WorkstationConsider heightReach zonesDesign

108

Supportive Active Sitting

Worker considerationsPostureVisionHealth and fitnessKnowledge



109

Active Sitting Environment

Proper chairAdjustable workstationHealth and wellness programsTraining programs

110

Questions?

Cindy Burt, MS, OTR/L, CPEUCLA Ergonomics Program Manager501 Westwood Plaza 4th FloorLos Angeles, CA [email protected]

Rani Lueder, Kageyu Noro, Steven Reinecke, Shunji Yamada ...The physician can deter mine this w ith...

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