seat comfort experience

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 dutch7. 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)+state (soft factors)

visual input noise smelltemperature/ humiditypressureposture/ 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

20-30º

20-30º

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 – 130o

-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 130o, seat 10o • 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:

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

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 dutch7. priming, expectations and experience

movement (synchro/dynamic) influences body length

(Dieën, 2002; Vink & Commissaris, 2005)

static chair syn chair dyn chair

static synchro dynchair 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 dutch7. 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 complaints3 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 dutch7. priming, expectations and experience

2nd truck seat activities observed

Relaxing readingsleepmusictelevision/games

Work laptopEating 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 100-130o

Seat angle 90-110o

Knee angle 130-155o

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 dutch7. 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

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

adaptations for small Asian woman and large Dutch man.

height adjustable pedals

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 dutch7. 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 dutch7. priming, expectations and experience

examination (1)

People using a hand held device have their neck mostly forward bendedA. 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 wasA. 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