Based on the latest scientific studies guidelines for a lounge chair are made. A lounge chair is designed and end users tested this chair again

1. the ideal lounge chair Prof dr Peter Vink Dori van Rosmalen, MSc TU-Delft/TNO email: Peter.vink@tno.nl

2. but what is ideal according to users? lounge chairs are everywhere

3. ideal regarding: 1. the process of experiencing comfort 2. the chair supporting a set of postures 3. the characteristics of the chair

4. 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

5. 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)

6. 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)

7. comfort no discomfort discomfort history (reference) + sta te (soft factors) visual input noise smell temperature/ humidity pressure posture/ movement (Vink, 2005)

8. do not mix up the sensory organs

9. ideal regarding: 1. the process of experiencing comfort 2. the chair supporting a set of postures 3. the characteristics of the chair

10. the chair supporting a set of postures -people do not sit in one position -humans do vary their postures

11. 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

12. more facts: 13975019345613985601394650139876508183650813476587252837039587061283046285706136405923640873406578270398748756029346508754721340825706135601839650385608135706138751356018365003426709245069274806928476924867924867204956798137698275827354762135498172346597816591385690813956812459812639548712369541872948279417825491872951295612389561326193271513825691865189365083745601836501

13. so, a lounge chair should stimulate to alternate various postures

14. feet off the ground!! observed while lounging at home watching a screen (Rosmalen et al., 2009)

15. 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)

16. ideal regarding: 1. the process of experiencing comfort 2. the chair supporting a set of postures 3. the characteristics of the chair

18. should fit: anthropometry most international human dimensions: www.dined.nl 306-398mm USA female: p5-p95 366-455mm

19. backrest should have a C-curve pressure in intervertebral disc Wilke, 1999

20. ideal back rest angle Most studies are visionary/guideline, some experiments: ___________________________________________ 130 o Rosmalen et al., 2009 comfort experiment 117 o Park et al., 2000 observing Korean drivers 120 o Hosea et al., 1986 EMG of back muscles 109 o Knijnenburg, 2007 comfort experiment 114 o Gscheidle, 2004 measurement office prefered positions ___________________________________________

21. 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)

22. ideal pressure distribution for car seat also for aircraft? (Zenk, 2008)

23. much more -shear forces -free shoulder space -back rest curve -seat curve -foam characteristics -activity specific guidelines -electronics in seats -……

24. this + 3 experiments = input for the design of a lounge chair (Rosmalen et al., 2009) -obervation at home - feet off the ground -comfort experiment – 130 o -probes

25. probes

28. ideal regarding: 1. the process of experiencing comfort 2. the chair supporting a set of postures 3. the characteristics of the chair

29. 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

30. 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.