the ideal lounge chair

Prof dr Peter VinkDori van Rosmalen, MSc

TU-Delft/TNO

email: Peter.vink@tno.nl

but what is ideal according to users?

lounge chairs are everywhere

ideal regarding:

1. the process of experiencing comfort

2. the chair supporting a set of postures

3. the characteristics of the chair

ingredients for a top comfort experience:

1. be aware of expectations and history

2. first sight should be comfortable

3. short term perfect

4. long term perfect

be aware of expectations and history

1. flying comfort correlated highest with comfort before the flight (r=.41, Konieczny, 2001)

2. business class and economy had no significant different comfort rating (Blok et al., 2008)

first sight should be comfortable

brown chair was seen as less comfortable, even while seated (Kuijt-Evers, 2001)

Bubb (2008) described similar result in car seats

first sight reaction can be measured by questioning, face reader or EMG of m.zygomaticus. Important as more sales is done by visual impression (internet)

comfort

no discomfort

discomfort

history (reference)+state (soft factors)

visual input noise smelltemperature/ humiditypressureposture/ movement (Vink, 2005)

do not mix up the sensory organs

ideal regarding:

1. the process of experiencing comfort

2. the chair supporting a set of postures

3. the characteristics of the chair

the chair supporting a set of postures

-people do not sit in one position

-humans do vary their postures

1777 Ramazini

2001 Dieen

(experiment)

2004 Lueder

(review scientific lit.)

static postures are hazardous

dynamic sitting increased body length significantly more than static sitting

constrained sitting is uncomfortable, contributes to chronic disorders, muscle pain, impaired circulation etc

more facts:13975019345613985601394650139876508183650813476587252837039587061283046285706136405923640873406578270398748756029346508754721340825706135601839650385608135706138751356018365003426709245069274806928476924867924867204956798137698275827354762135498172346597816591385690813956812459812639548712369541872948279417825491872951295612389561326193271513825691865189365083745601836501

so, a lounge chairshould stimulate

to alternate various postures

feet off the ground!!

observed while lounging at home watching a screen (Rosmalen et al., 2009)

other possibilities to vary

significant effects measured by:-massage system (Franz et al., 2008)-changing the tasks/activities (Ellegast et al., 2008) -changing the back rest angle (Groenesteijn et al., 2009)

ideal regarding:

1. the process of experiencing comfort

2. the chair supporting a set of postures

3. the characteristics of the chair

characteristics of the chair

(given various postures and perfect comfort at first sight) for a certain posture the chair:

•should fit•have a C-curve•ideal back angle•ideal pressure distribution

should fit: anthropometry

most international human dimensions: www.dined.nl

306-398mm

USA female: p5-p95

366-455mm

backrest should have a C-curve

0

0,2

0,4

0,6

0,8

1

1,2

laying standing bending sitting 1 sitting 2

pres

sure

in

MPa

pressure in intervertebral disc

Wilke, 1999

ideal back rest angle

Most studies are visionary/guideline, some experiments:___________________________________________130o Rosmalen et al., 2009 comfort experiment117o Park et al., 2000 observing Korean drivers120o Hosea et al., 1986 EMG of back muscles109o Knijnenburg, 2007 comfort experiment114o Gscheidle, 2004 measurement office

prefered positions___________________________________________

ideal back rest angle

Harrison et al. (2000) for a 5º tilted seat 100º trunk position is preferable watching the road>100º increases neck flexion

position of the back depends strongly on the task (Dunk & Callaghan, 2005: Groenesteijn et al., 2009)

ideal pressure

distribution for car seat

also for aircraft?

(Zenk, 2008)

much more-shear forces

-free shoulder space

-back rest curve

-seat curve

-foam characteristics

-activity specific guidelines

-electronics in seats

-……

this + 3 experiments

= input for the design of a lounge chair

(Rosmalen et al., 2009)

-obervation at home - feet off the ground

-comfort experiment – 130o

-probes

probes

• stimulate different sitting positions with one chair• variable armrests • feet off the ground• support the body, where needed • backrest 130o, seat 10o • head support • stuff space

Design Van Rosmalen

design criteria

of course the comfort of the chair was high,specific comments of 13 end users:

height arm height back seat head support support depth support

too high: 2x too high: 0x too deep: 1x too far forw: 2xgood: 11x good: 9x good: 10x good: 2xtoo low: 0x too low: 4x too short: 2x too far backw:4x

effects

ideal regarding:

1. the process of experiencing comfort

2. the chair supporting a set of postures

3. the characteristics of the chair

so, the ideal lounge chair should

-stimulate to vary postures-support feet off the ground-fit to the human size-have a C-curve-have an ideal back angle-have an ideal pressure distribution-be based on probes-be tested-which makes me happy

References-Blok M, Vink P, Kamp I. Comfortabel vliegen: comfort van het vliegtuiginterieur door de ogen van de gebruiker. Tijdschrift voor Ergonomie 2007;32(4):4-11-Bubb, R. Sitting comfort, presentation at IQPC aircraft interior innovation, 2008-Dieën JH van, Looze MP de, Hermans V. Effects of dynamic office chairs on the low back. Ergonomics 2001;44:739-50.-Dunk NM, Callaghan JP, Gender-based differences in postural responses to seated exposures. Clinical Biomechanics 20 (2005) 1101–1110-Ellegast R, Keller K, Hamburger R, Berger H, Krause F, Groenesteijn L, Blok M, Vink P. Ergonomische Untersuchung besonderer Büroarbeitsstühle. Sankt Augustin, BGIA, 2008-Franz M, Zenk R, Durt A, Vink P. Disc Pressure Effects on the Spine, Influenced by Extra Equipment and a Massage System in Car Seats. In: Human Factors in Driving, Seating Comfort and Automotive Telematics, 2008. (SP-2210). SAE Technical Paper Series 2008-01-0888-Groenesteijn L, Vink P, Looze M de, Krause F. Effects of differences in office chair controls, seat and backrest angle design in relation to tasks. Accepted for publication in Applied Ergonomics 2009-Gscheidle GM, Reed MP, Sitter-selected postures in an office chair with minimal task constraints, In: Proceedings of the Human Factors and Ergonomics Society 48th Annual Meeting 2004, 1086-1090-Harrison DD, Harrison SO, Croft AC, Harrison DE, Troyanovich SJ, Sitting Biomechanics, Part I1: Optimal Car Driver's Seat and Optimal Driver's Spinal Model. Journal of Manipulative and Physiological Therapeutics 23(1), 2000: 37-47-Hosea TM, Simon SR, Delatizky J, Wong MA, Hsieh CC. Myoelectric analysis of the paraspinal musculature in relation to automobile driving. Spine 1986; 11:928-36.-Knijnenburg, R. Future passengers side truck seat for DAF, confidential, TU-Delft, 2007 -Konieczny G, Die Messung und steigerung der Qualität von Dienstleistungen in der Flugzeugcabine – ein Beitrag zur Kundenorientierten Flugzeugentwicklung, Dissertation, TU Berlin, 2001-Kuijt-Evers et al., 2001, in: Bronkhorst R.E., Kuijt-Evers L.F.M., Cremer R., Rhijn J.W. van, Krause F., Looze M.P. de, Rebel J. Emotion and comfort in cabins: report TNO, Hoofddorp, Publ.nr. R2014871/4020054. 2001-Lueder, R, 2001, Ergonomics of the seated movement. A review of the scientific literature, Humanics Ergosystems, Encino-Park SJ, Kim Ch, Kim CJ, Lee JW. Comfortable driving postures for Koreans. International Journal of Industrial Ergonomics 26(4), 2000, 489-497-Ramazzini (1777) Essai sur les Maladies de Disseus-Rosmalen D van, Groenesteijn L, Boess S, Vink P. Seat comfort requirements for watching a screen, submitted for publication in J of Design Research-Vink, P (ed.) (2005), Comfort and design, CRC Press, Boca Raton-Wilke, H.J., Neef, P., Caimi M., Hoogland T. & Claes L.E (1999). New in vivo measurements of pressures in the intervertrebal disc in daily life. Spine 24(8): 755-762 -Zenk, R. Objektivierung des Sitzkomforts und seine automatische Anpassung, dissertation TU München, 2008.