Seat comfort experience Prof dr Peter Vink TU-Delft/TNO email: Peter.vink@tno.nl

this workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truckseat) 6. small asians and tall dutch 7. priming, expectations and experience

• Observe assignment

• Observe these slides of people sitting - with a hand held device:

• Neck: bended, Arms: supported

• Sitting relaxed:

• Legs: stretched, Legs and arms: supported

• -Sitting watching:

• Back: supported, Neck: upright, Arms: supported

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

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

seats should support many 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

feet off the ground!! observed while lounging at home watching a screen (Rosmalen et al., 2010)

much variation in posture watching TV

additional movements observed while lounging at home watching a screen (Rosmalen et al., 2010)

Kroemer et al., 2001 seat profile indicated by spine curve 20-30 20-30

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

much more -shear forces -free shoulder space -lines in the cushion -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 130 o -probes

• LPD 10 subject 36 minutes in each condition

• B best back rest

• C better because of head rest

experiment

probes

• stimulate different sitting positions with one chair

• variable armrests

• feet off the ground

• support the body, where needed

• backrest 130 o , seat 10 o

• head support

• stuff space

Design Van Rosmalen design criteria

the seat

• of course the comfort of the chair was high,

• specific comments of 13 end users:

effects height arm height back seat head support support depth support too high: 2x too high: 0x too deep: 1x too far forw: 2x good: 11x good: 9x good: 10x good: 2x too low: 0x too low: 4x too short: 2x too far backw:4x

This workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truckseat) 6. small asians and tall dutch 7. priming, expectations and experience

• movement (synchro/dynamic) influences body length

• (Dien, 2002; Vink & Commissaris, 2005)

static synchro dyn chair chair chair Body length increas Sign* 1. movement in the chair

2. feet movement

3. several pillows

4. massage Lumbar disc pressure (Pascal) according to Franz et al. (2010)

Ideas for movement? Rotating seat Seat pan dynamics Stimuli to move (vibration/tickling) Breaks for walking Exercise stimuli in seat etc

This workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truck seat) 6. small asians and tall dutch 7. priming, expectations and experience

Looze et al. 2003: Most evidence relationship discomfort-pressure distribution and posture EMG is sometimes related to comfort (Kuijt-Evers, 2005) Comfort good to measure by questionnaire (Vink, 2005), e.g. LPD

Pressure distribution

Discomfort LPD measurement

• Preventing neck/back complaints

• 3 year follow up (Hamberg et al., 2008):

• Peak LPD (>2, scale 0-10):

• RR 1,79 low back pain (n=865)

• RR 2,56 neck pain (n=1001)

• Cumulative LPD (sum>3 of 6 measurements/day)

• RR 2,35 neck pain (n=2342)

Discomfort important for

This workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truck seat) 6. small asians and tall dutch 7. priming, expectations and experience

2nd truck seat activities observed Relaxing reading sleep music television/games Work laptop Eating drinking/eating cooking

design + ideas tested 1 Watching a screen above the front window feet on the dashboard 2 Watching a screen partly rotated with the screen in the right angle 3 Watching a screen above the driver door sitting 90 degrees rotated Truck drivers prefer 3

ideal position tv watching Test 20 subjects 10 min various postures (Knijnenburg, 2003) Comfortable back rest angle 100-130 o Seat angle 90-110 o Knee angle 130-155 o

This workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truck seat) 6. small asians and tall dutch 7. priming, expectations and experience

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

• RET wants new tram:

• Good for fat and small tram drivers

• No back complaints

• High comfort

• Safe (1 m high object should be seen 1 m close to the tram)

tram cabin design old

• Management + end-users + Bombardier (designer + manufacturer) + ergonomists

• Adapt existing design

• Including several end-user

• tests with mock-up

• Main problem: small asian drivers and fat large Dutch

approach

height adjustable pedals adaptations for small Asian woman and large Dutch man .

less complaints, more possibilities to look for new drivers results:

This workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truck seat) 6. small asians and tall dutch 7. priming, expectations and experience

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)

emocard experiment now First define what emotions you want by seeing an office chair

This workshop: 1. observe (assignment) 2. global design (loungechair) 3. variation while seated (4 possibilities) 4. methods to test comfort (assignment) 5. iterative test-design (truck seat) 6. small asians and tall dutch 7. priming, expectations and experience

examination (1) People using a hand held device have their neck mostly forward bended A. yes B. no The next of the two postures has the highest lumbar disk pressure according to Wilke (1999) A. standing B. sitting with the back rest backwards

examination (2) The longest observed duration in one position watching TV in the Rosmalen study was A. 30 minutes B. 50 minutes Dynamics in the office seat compared with a static seat resulted in A. increased body length B. Less reduction of body length

examination (3) The most valid objective measurement related to discomfort is according to Looze, 2003 A. EMG B. Pressure distribution According to Knijnenburg truck drivers prefer for the passenger seat a back angle of A. 100-130 degrees B. 90-110 degrees

examination (4) The color of the seat influences A. Short term comfort B. Long term comfort This workshop was presented by A. Bart Koenamaosiros B. Peter Vink

More information

• Vink P, Looze MP de. Crucial elements for designing comfort. In: Schifferstein NJ, Hekkert P, Eds. Product experience. Amsterdam: Elsevier, 2008:441-459.

• Vink P, ed. Comfort and Design: Principles and Good Practice. Boca Raton (etc.): CRC Press, 2005