Design-relevant ergonomic data on Dutch elderly

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Design-relevant ergonomic data on Dutch elderlyL.P.A. Steenbekkers , C.E.M. van Beijsterveldt , J.M. Dirken , J.J. Houtkamp , J.F.M. Molenbroek &A.I.M. VoorbijPublished online: 09 Aug 2010.

To cite this article: L.P.A. Steenbekkers , C.E.M. van Beijsterveldt , J.M. Dirken , J.J. Houtkamp , J.F.M. Molenbroek & A.I.M.Voorbij (1999) Design-relevant ergonomic data on Dutch elderly, International Journal for Consumer and Product Safety, 6:3, 99-115

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99Ergonomic data on Dutch elderly

Correspondence andreprint requests to:Ms L.P.A. SteenbekkersWageningen Agric UnivSubdept Household &Consumer StudiesP.O. Box 80606700 DA WageningenThe NetherlandsTel.: +31 317 482594

Original paper

International Journal for Consumer &Product Safety 1387-3059/99/US$ 15.00

International Journal for Consumer &Product Safety – 1999, Vol. 6, No. 3,pp. 99-115© Æolus Press 1999

Accepted 17 November 1998

Design-relevant ergonomic data on Dutchelderly

L.P.A. Steenbekkers,C.E.M. van Beijsterveldt, J.M. Dirken,

J.J. Houtkamp, J.F.M. Molenbroek,A.I.M. Voorbij

Delft University of Technology, Subfaculty of Industrial DesignEngineering, Delft, The Netherlands

Abstract The design of daily-life products that can be used in asafe and comfortable way by many consumers requires ergonomic dataconcerning these users. With regard to the elderly, hardly any ergo-nomic data were available.

In this study, measurements were done on about 79 physical, psycho-motor, sensory and cognitive variables. The sample consisted of 750persons: 123 in the age between 20 and 30 years and 623 aged 50 yearsand over.

The results reveal different patterns of level and variation with age.Generally speaking, the physical data exhibit a relatively small varia-tion with age; in other words, the variation within age groups is muchlarger. For the psychomotor and sensory variables variance generallyincreased with age. Especially after the age of 65 or 70 the level ofperformance decreased compared to that of younger subjects.

As far as differences between the sexes are concerned, it is concludedthat there are marked differences in the physical variables betweenmales and females. Body build and the amount of force exerted differ.The psychomotor variables also show systematic differences betweenmen and women. For the sensory and cognitive variables, few system-atic differences between the sexes were found.

People with capacities in the lower percentiles of the frequency dis-tribution appear to have difficulties in performing daily-life activities.However, they still manage to live independently. This is possiblebecause they use all kinds of solutions to compensate for the lowerlevel of ability.

Key words Ergonomics; elderly; product design; aging

Introduction The increasing number of elderly in our western so-ciety requires durable consumer goods and public space adapted to thecapacities and capabilities of that part of the population. The design of

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products suitable to be used by all consumers requires data on thedesign-relevant capacities of these future users.

It is generally known that with increasing age several capacities de-crease or change. This influences the ability to use products or to movearound in public space. The fact that the elderly are often victims ofaccidents in and around the home in which products are involved1

points to the possibility that not all products are sufficiently adapted tothe capacities and characteristics of these users. In order to be able todesign products that are more suited for use by the elderly as well, dataon their capacities and characteristics are needed.

In this connection, some data on the Dutch elderly are available, butfor many characteristics these data are lacking. Therefore, a study wasinitiated in which design-relevant capacities and characteristics of se-nior citizens have been assessed.

Objective The research questions addressed by this study were:1. Which physical, psychomotor, sensory and cognitive capacities of

the elderly are relevant to the design of durable daily-life products?2. Is it possible to quantify these characteristics and, if so, what level

do they have and how much variation do they exhibit?3. Are there ways to compensate for decreasing or changing capac-

ities?

When these questions are answered the following goals of the projectwill have been met:

1. To describe and quantify the physical, psychomotor, sensory andcognitive characteristics of Dutch users of consumer products in theage group between 20 and 30 and over 50 years of age, resulting in adatabank of human characteristics, relevant to the design and innova-tion of equipment for daily living.

2. To compare these capacities of different age groups of adults, andthus contribute to various theories on the aging of ability.

3. To generate design guidelines for designers of durable daily-lifeproducts, based on the measurement of capacities.

Methods The number of subjects per age group and sex is given inTable 1. Several methods were used to recruit the subjects: a randomsample was drawn from the municipal register, people were asked tovolunteer in an article in some regional newspapers, and members ofthe pensioners’ society of the university also participated.

All subjects were ‘healthy’ (they had not been to a medical specialistfor treatment in a period of three months prior to taking the measure-ments) and living independently. This, however, does not mean that thesubjects did not have any physical complaints. The age group between20 and 30 years was included as the reference group.

The level of education of the subjects was higher than that of the totalDutch population. However, it is not clear whether this could have aneffect on the capacities measured in this study.

choice of the variables The variables assessed in this study canbe grouped into four categories: physical (e.g. body dimensions, forces,

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range of movement of joints, reaching envelopes, walking velocity,step height), psychomotor (gross and fine motor skills, reaction time),sensory (visual, auditory and tactile capacities) and cognitive (memory,preference for color) variables. The variables in each of the groupswere determined by means of two methods: interviews with experts onthe difficulties encountered by the elderly with products for daily liv-ing2 and, secondly, our experience with design projects and the ques-tions designers have asked about the variability of characteristics. Allvariables chosen are expected to change with age. An overview ofthese variables and some examples of the application of the data aregiven in the appendix.

method of measurement Where available, existing methods wereused in order to be able to compare our results with those from otherstudies. However, a number of existing methods would lead to resultsthat are less suitable to be used for design purposes. In that case, wedefined our own method of measurement. In these measurements, wetried to imitate daily-life practice as much as possible. This implies, forexample, that subjects wore their own glasses, which might not correctto optimal vision anymore, because the glasses might already be someyears old. For the exertion of force we did not prescribe the position inwhich a measurement should be performed, but encouraged the sub-jects, e.g. to push as hard as possible as if opening a heavy door.

Results In this paper, some of the main results of the study aredescribed. A complete description of the data as well as the methods ofmeasurement is available in the book by two of the present authors.3

physical variables

Body dimensions In this study, 26 body dimensions were assessedand four were calculated on the basis of these 26. Examples of dimen-sions assessed are stature, body mass, dimensions of body segments,dimensions of the hand and foot, etc.

For 17 variables, the mean values for younger and older subjectsappear to be different. However, the effect of sex is larger. For allvariables but one (abdominal depth) significant differences in meanvalues for men and women are present. For all but two variables (hipbreadth, sitting and thigh clearance, sitting) the mean values for menare larger than those for women. To illustrate an example of theseresults, the data for stature are given in Fig. 1.

age group men women total

20–30 55 68 12350–59 81 85 16660–69 94 104 19870–79 95 100 19580+ 33 35 68

total 358 392 750

table 1. Number of subjects in thisstudy according to age group and sex.

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In order to see whether there were common patterns in the bodydimensions, factor analysis was applied; this revealed four factors: alength- or segment factor, a trunk factor, an extremities factor and amass factor. When age and sex were included in the analysis, ageloaded negatively on the trunk factor and sex also loaded negatively onthe extremities factor. This means that older subjects have relativelysmaller trunk-related dimensions and the extremities of women aregenerally smaller than those for men.

Exertion of force Four types of force were assessed in this study:pushing with two hands, pulling with one hand, gripping force andtorque with two hands. The results show the expected effect of age andof sex. The latter was largest: men are stronger than women. Womencan exert about 60-68% of the amount of force exerted by men. Gen-erally speaking, the younger subjects were stronger than the subjectsabove the age of 60. Figure 2 depicts an example of the decline ofpushing force with age. It also shows the sex differences.

Range of movement of joints Maximum ranges of movement of theneck and the wrist of the dominant hand were assessed, for both jointsin six directions. Also, the flexion of the forefinger was measured. Allmeasurements started with the joint in the neutral position. Because itis relatively difficult to measure this type of variables, all measure-ments were taken twice. For all variables in this group, except for theradial deviation of the wrist, an effect of age was present: the maxi-mum ranges of joint movement decrease with age. An effect of sex waspresent only for the range of movement of the wrist: wrist flexibilitywas greater in women than in men.

Fig. 1. Mean stature [cm] and 5th and95th percentile according to age groupand sex.

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Reaching envelopes Four reaching envelopes were assessed: comfort-able and maximum reach in the vertical plane while standing and com-fortable and maximum reach in the horizontal plane while sitting. Aneffect of age was present: the reaching envelopes decreased with in-creasing age. The effect of sex disappeared when stature was taken intoaccount.

Step length and walking velocity Here, three measurements were tak-en: step length and walking velocity at a normal and at a hurried pace.The results show an effect of both age and sex. Both step length andwalking velocity decreased with age and women showed smaller meanvalues than men. This effect remained when the results were correctedfor leg length.

Step height Four measurements were assessed: comfortable and max-imum step height, both when ascending and descending. An effect ofage was present for all step measures. In general, the step heightsdecreased with increasing age, but the effect was larger for the maxi-mum step heights than for the comfortable heights. An effect of sexwas also present: women take smaller steps than men, and this effectremained when a correction for leg length was applied.

Variability of the physical variables with increasing age Variance ofhuman characteristics can be expected to increase with increasing age.To test this, the variation coefficients were computed. The variationcoefficients for the body dimensions were relatively small and remainedat the same level for successive age groups. For the functional vari-ables, the variation coefficients were already relatively large at youngerages and still increased with age. This points toward larger differencesin these functional capacities between subjects of older ages.

Fig. 2. Mean pushing force [N] and 5th

and 95th percentile according to agegroup and sex.

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To compare the effect of age on the representative physical variables,standardized z-scores were computed for each age group relative to theresults of the youngest age group. These representative variables wereassessed on the basis of factor analysis. These results are shown inFig. 3.

psychomotor variables

Hand steadiness For this task, the subject had to put a pen into holesof decreasing diameter, without touching the brim. The diameter of thesmallest successful hole was recorded as the score. The results showedthat an effect of age was present for this task: the younger subjects (20-30 years of age) performed better than those aged 60 years and over.The oldest subjects performed worse than most younger age groups.The expected difference in fine-motor skills between men and womenwas also present: women performed better than men.

Eye-hand co-ordination This characteristic was assessed by means ofa standard test in which the subject had to put 25 pins in a hole as fastas possible (the pegboard test). The time needed to finish this task wasrecorded. Age effects were expected and were present in this sample.As shown in Fig. 4, most age groups differ from each other and afterthe age of 65 years there is a marked decrease in performance. Con-trary to expectations no differences between men and women appeared.

Reaction time Reaction time was assessed by means of simple andchoice tasks, in which the subject had to react as fast as possible toeither visual or auditory stimuli, according to the method described byEra et al.4 Generally speaking, an effect of age was expected and found.The young reacted faster than the subjects over 65 years of age and the

Fig. 3. Standardized z-scores for therepresentative physical variables,relative to the youngest age group.Age group 1 = 20-30 years of age, 2 =50-54, 3 = 55-59, 4 = 60-64, 5 = 65-69, 6 = 70-74, 7 = 75-79, 8 = 80+.

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oldest subjects performed worst. For choice reaction time this effectwas more pronounced than for the simple tasks. As expected, mengenerally reacted somewhat faster than women.

Reaction to an auditory stimulus proved to be generally slower thanthat to a visual stimulus. A choice reaction required more time than asingle stimulus.

Balance A balance test was performed in two conditions: balancewith the eyes open and with the eyes closed. In each condition, theshod subject had to stand on one leg as long as possible. The maximumtime set was 60 seconds. An effect of age was present in the sense thata decrease in balance time was found for the older age groups. Sexdifferences were present only for balance with the eyes closed: menperformed better than women. In the test with the eyes open no differ-ences between the sexes were present. The results of balance with theeyes open are given as an example in Fig. 5.

Variability of the psychomotor variables with increasing age Heretoo, variation coefficients were computed to see whether the expecta-tion that variance increases with age could be confirmed. Indeed, thevariation coefficients increased with age, implying that differences be-tween subjects of the same age increase as individuals grow older.

Except for balance with the eyes closed, a gradual decline with agewas found, which became more rapid after the age of 75 years. Balancewith the eyes closed appeared to have already decreased markedly inthe age group 50-54. Afterwards, it remained quite stable but at a lowlevel, compared to the youngest subjects. This is shown in Fig. 6,which presents the standardized z-scores relative to the youngest sub-jects for the representative variables in the psychomotor group.

Fig. 4. Mean time for the test on eye-hand co-ordination and 5th and 95th

percentile according to age group andsex.

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sensory variables

Near-reading visual acuity This variable was assessed by means ofthe Landolt-C test, which was reduced photographically to be used atreading distance (about 40 cm.). For this test, daily-life circumstanceswere simulated in the sense that the subjects wore their own glasses,which might not have corrected optimally anymore because the glassesmight already be some years old. This implies that eyesight was notcorrected to optimum before the test was done, which is common prac-tice in other studies on visual acuity. As expected, an effect of age was

Fig. 5. Mean balance time with theeyes open and 5th and 95th percentileaccording to age and sex.

Fig. 6. Standardized z-scores for therepresentative psychomotor variables,relative to the youngest age group.Age group 1 = 20-30 years of age, 2 =50-54, 3 = 55-59, 4 = 60-64, 5 = 65-69, 6 = 70-74, 7 = 75-79, 8 = 80+.

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present: the youngest subjects performed better than all other age groups.The oldest individuals performed worse than the subjects younger than75 years of age. No differences between men and women were shownfor this variable. The results are given in Fig. 7. The larger the score,the better the near-reading visual acuity.

Visual contrast sensitivity This variable was measured using a read-ing test in which the subjects had to read text blocks of different lettersizes and of different contrast in various levels of illumination.5 Again,an effect of age was shown. Four groups could be identified whichperformed at different levels: 20-30 years of age, 50-69, 70-79 and 80years and over. No systematic differences in performance between thesexes were found.

The level of illumination proved to be the most important factor forthe performance of the elderly. At low levels of illumination they couldread only relatively large letters, irrespective of contrast. Under highlevels of illumination the contrast also influenced readability. For theyounger subjects contrast influenced readability positively at low levelsof illumination. When illumination increased, they hardly gained inreadability because the maximum levels of performance had alreadybeen reached.

Auditory capacities A pure tone audiogram for the right and left earwas assessed. Many specific results were found, but only general con-clusions will be summarized here. As expected, an effect of age wasfound here too. This was more pronounced for the higher tones than forthe lower frequencies. While 25% of the subjects 65 years of age andolder were unable to hear tones of 6000 Hz or higher, this was true for68% of the oldest subjects (80+) in our sample. Generally speaking,men had higher thresholds than women, especially for the frequencies

Fig. 7. Mean visual acuity and the 5thand 95th percentile according to ageand sex.

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above 3000 Hz. In contrast, for the lower frequencies, the thresholdsfor women appeared to be somewhat higher.

Tactile capacities This rather infrequently assessed capacity is mea-sured with a test on form recognition. In this test, pairs of forms hadto be felt with the tip of the forefinger. It had to be decided whetherthese two forms were equal or not. These pairs could be equal ordifferent in either size, line thickness or shape. Both the time neededand the correctness of the answer were recorded.

Form recognition appeared to decrease with age, but only after theage of 70 years. The largest differences were present between the young-est and the oldest age groups. No differences between sexes were presentwith respect to the time needed to arrive at an answer. The number oferrors, however, differed: women made fewer errors than men.

Variability of the sensory variables with increasing age The stan-dardized z-scores (Fig. 8) showed a slight decrease in performance onthe tactile variables. For the visual and auditory capacities this decreasewas most prominent between the youngest age group and the subjectsbetween 50 and 54 years of age. After that age, only a gradual decreaseremained. Because data on the age group between 30 and 50 years werelacking, it could not be determined more precisely when this deterio-ration starts.

cognitive variables

Memory Two tests were used to test memory: the digit span to deter-mine explicit memory and a test of implicit memory assessed by askingtwo questions related to the measurements done in one of the sessions.An effect of age was present for both tests, although it became marked

Fig. 8. Standardized z-scores for therepresentative sensory variables,relative to the youngest age group.Age group 1 = 20-30 years of age, 2 =50-54, 3 = 55-59, 4 = 60-64, 5 = 65-69, 6 = 70-74, 7 = 75-79, 8 = 80+.

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only after the age of 75 years. No difference in performance was seenbetween the sexes.

Preference for color Preference for color was assessed in general aswell as related to different types of products. Only small differences inpreference for color were present between the age groups. Red was ingeneral the most preferred color. As expected, the preferred colorswere closely related to kind of product. Some differences between thepreferred colors of females and males were seen: males preferred grassgreen and orange more often than women and women preferred darkgreen and blue more often.

the adl-questionnaire In a written questionnaire, 44 questionswere asked about the problems experienced in daily-life situations andwith durable consumer products (see also the article by Hoonhout andSteenbekkers6). Generally speaking, the subjects above the age of 75experienced more difficulties in daily life, especially when an activityrequired physical effort. Women also appeared to have more difficultyin performing activities that require physical effort. Devices to openpackages or to facilitate other situations or activities were used less bymen.

Most problems seemed to be caused by physical complaints of thesubjects. Despite diminished abilities, all subjects managed to live in-dependently. This was possible because all kinds of compensationswere used. This varied from not using products anymore to using themin a different way than before, or asking another person to assist or dothe activity for them.

In order to see whether the level of performance of the laboratorymeasurements has predictive value for difficulties experienced in dailylife, the answers on the ADL-questionnaire were compared with thelevel of functioning as measured in the laboratory. It was expected thatthe lower percentiles of the population would report more difficultiesin daily life than the higher percentiles. The mean values of the an-swers on the questionnaire for these extreme groups (<P10 and >P90)on the laboratory measurements were compared. Almost all differencesin mean values appeared to be statistically significant. The subjectswho performed relatively worse on the laboratory measurements alsogenerally reported more difficulties in daily life. The absolute differ-ences were, however, small. It might therefore be concluded that lowscores for the laboratory measurements have some, albeit a very lim-ited, predictive value for experiencing difficulties in daily life.

Conclusion In this study, 750 subjects participated in the mea-surement of 79 variables. The results of these measurements form adatabank of design-relevant capacities and characteristics of the Dutchpopulation between 20 and 30 and above 50 years of age.

Although design-relevance was not confirmed for all variables, ourexperience with design projects supports our idea of the applicability ofmost of the data. Because subjects in the lower percentiles of the fre-quency distribution reported more difficulties in daily-life situations,these data in particular should be taken into account.

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The results reveal different patterns of level and variation with age.Generally speaking, the physical data, representing the anatomical struc-ture, exhibit a relatively small variation with age; in other words, thevariation within age groups is much larger. Therefore, differences be-tween individuals of the same age are generally larger than differencesbetween individuals of successive age groups. This is partly explainedby the large differences between sexes found for this group of vari-ables. For the psychomotor and sensory variables, the variance gener-ally increased with age. Especially after the age of 65 or 70 the levelof performance decreased compared to that of younger subjects.

The influence of age also differed between the groups of variables.When the results are presented relative to those of the younger sub-jects, some variables show a more or less linear decline (e.g., walkingvelocity), whereas others either remain constant over a fairly prolongedperiod of time or decrease only among subjects of higher ages (e.g.,eye-hand co-ordination). Relatively few physical variables exhibited anincrease with age (abdominal depth, ear length).

As far as the differences between the sexes are concerned, it can beconcluded that there are marked differences in the physical variablesbetween males and females. Body build and the amount of force exert-ed differ. As expected, men are generally taller and stronger. The psy-chomotor variables show systematic differences between men andwomen. When the variables are fine-motor skills, women are betterthan men. The gross motor variables, however, hardly differ. For thesensory and cognitive variables few systematic differences between thesexes were found. Men and women perform these ‘higher’ or ‘moreinternal’ functions at equal levels and with the same variations.

People with capacities in the lower percentiles of the frequency dis-tribution appear to have difficulties in performing daily-life activities.However, they still manage to live independently. This is possiblebecause they use all kinds of solutions to compensate for the lowerlevel of capacity. This can mean performing more slowly, using othercapacities, setting lower standards for comfort or using fewer daily-lifedevices or using them less often. Reliance on others is also a commonalternative solution for specific activities, which need not always seri-ously threaten independence.

application of the data The data of this study can be consid-ered to constitute an important collection of design-relevant capacitiesand characteristics of Dutch users of different ages. One remark on thedesign relevance should, however, be added. In principle, all variablesare single aspects that might play a role in the complex activity ofhandling and using products. In daily life, however, the use of productsrequires a combination of several of these capacities and characteristicsevery time. How the data should be combined in order to obtain an‘overall picture’ of those capacities that are considered to be relevantwas not the objective of this study. Furthermore, no one person willhave a low score for all variables. The compensation of one capacityby another may also determine the specific approach by an individualuser. Product designers, however, who usually aim at comfortable andeffective use by a broad group of people, must as a rule presume low

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levels for all capacities and characteristics relevant to the use of thespecific product.

design guidelines For each variable, in order to help the users tointerpret and use the data in a correct way, a general application of thedata, examples of products and warnings, tips and tricks have beenpresented, as well as design guidelines. It is not possible to present allthis information here, but some illustrative examples of design guide-lines are given below.

Stature • For passageways, the tallest (e.g. P99) male shouldbe the reference point. Additions may be necessaryfor helmets (8 cm) or boots (4 cm). For walking, anextra 5 cm is required.

Pushing force • The elderly are less strong in this respect; take theirdata as a starting point.

• For the solidity of constructions the strongest indi-vidual has to be used as the criterion, but it is wiseto add a safety margin.

• For handling products, the weakest individual (oreven less) must be used as the criterion.

Eye-hand • If accurate reaching is required for good consumer-co-ordination product interaction, the target and its orientation

should be very clear visually and, if possible, posi-tioning of the object should be guided by a taperingconcavity.

• If accurate positioning is required, the presence andorientation of the hand-held or hand-contacted ob-ject should be pronounced and clearly felt by thefingers and hand.

Balance • Mount or supply supports where the elderly need orwill probably need them. In many cases, youngerusers will welcome these supports as well.

• Grips should be near at hand, within the reflex area,easily visible and firm.

• Grips should be mounted and grasped and held at aheight that accommodates both short and tall indi-viduals.

Visual acuity • For short important messages, use a 12-point sans-serif, lower case alphabet.

• Design a visual message according to its importanceby juggling size, illumination, place, lay-out, addi-tional figures, etc.

• Legibility is sometimes designed properly, whilecomprehensibility of the text is badly neglected. Meetboth requirements.

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compared with self-report visualdisability. In: Kooijman AC,Looijestijn PL, Welling HJ, Van derWildt GJ, editors. Low Vision:Research and new developments inrehabilitation. Amsterdam: IOS Press,1994.

6 Hoonhout HCM, Steenbekkers LPA.Als alledaagse handelingen voorouderen een struikelblok worden;gebruikersfactoren of ontwerptekort-komingen? Tschr Ergon1998;23(4):106-16.

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Appendix

Overview of the variables assessed in this Gerontotechnology project.

variable examples of application

physical variablesbody dimensions

1 body mass solidity of constructions2 stature general dimension for comparison with other sources, door

height, shower height3 fist height grip height of shopping trolley, cane4 sitting height height of a backrest, including headrest5 eye height, seated height of intercom, door-plate, signs, etc. for wheelchair-users6 shoulder height, seated indication of the height of a back rest7 frontal grip reach, seated reference for reaching envelopes8 upper arm length to compute the elbow height, seated; to indicate the height of

an armrest9 elbow – grip length indicates the distance to grip something

10 elbow – finger tip length indicates the length of an arm-rest11 shoulder breadth width of a backrest

(bi-deltoïdus)12 breadth across the elbows indicates the minimum width of a corridor13 hip breadth, seated indicates the width of a seat, bathtub14 buttock – popliteal length seat depth15 buttock – knee length indicates the minimum distance between two rows of seats16 popliteal height seat height17 abdominal depth distance between back of a chair and the steering wheel of a car18 thigh clearance, seated indicates the minimum distance between seat and underside of

table19 hand length safety requirement to keep the hand from getting stuck between

parts, gloves20 hand breadth without thumb grips, door handles21 thumb breadth size of controls22 forefinger tip breadth size of push-buttons23 grip diameter maximum diameter of grips24 foot length step, foot board25 foot breadth width of a pedal26 ear length headphones, earmuff27 eye height, standing height of peep-hole, fixed binoculars28 shoulder height, standing maximum height for comfortable grasping of products29 elbow height, standing height of counter30 elbow height, sitting height of elbow rests

forces31 maximum gripping force products which require maximum squeezing force

of one hand32 pushing force with two hands heavy doors that have to be pushed open33 pulling force with one hand moving loads or products34 static torque with two hands jars, caps

range of movement of joints35 flexion of the head tilted writing surfaces

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36 extension of the head height of important information in public spaces37 lateral bending of the head reading titles of books on shelves in a library

towards the right38 lateral bending of the head reading titles of books on shelves in a library

towards the left39 rotation of the head toward looking to the right in traffic

the right40 rotation of the head toward looking to the left in traffic

the left41 flexion of the wrist hand breaks, gas handles42 extension of the wrist grips on crates43 radial deviation of the wrist computer mouse44 ulnar deviation of the wrist width of keyboards, computer mouse45 pronation turning controls, tap46 supination turning controls, tap47 forefinger flexion manipulation of small objects

reaching envelopes48 envelope of comfortable situations in which individuals have to reach for products or

vertical reaching, standing parts often49 envelope of maximum situations in which individuals have to reach for (lightweight)

vertical reaching, standing products incidentally50 envelope of comfortable situations in which individuals have to reach for products or

horizontal reaching, sitting parts often51 envelope of maximum situations in which individuals have to reach for (lightweight)

horizontal reaching, sitting products incidentallystep length and step height

52 step length space required to walk behind a carriage53 walking velocity, ‘green time’ for traffic lights for pedestrians

normal pace54 walking velocity, time required to cross a distance faster than normal

hurried pace55 comfortable step height, stairs, kitchen steps

ascending56 comfortable step height, stairs, kitchen steps

descending57 maximum step height, access to public transport

ascending58 maximum step height, exit from public transport

descendingpsychomotor variablesfine motor skills

59 hand steadiness thread through eye of a needle60 eye-hand co-ordination keys in keyholes, money in machine slots

reaction time61 reaction time, simple task, warning lights, traffic lights

visual stimulus62 reaction time, simple task, doorbells, warning signals in public domain

auditory stimulus63 reaction time, choice task, warning lights, traffic lights

visual stimulus

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64 reaction time, choice task, doorbells, warning signals in public domainauditory stimulus

65 movement time, simple warning lights, traffic lightstask, visual stimulus

66 movement time, simple doorbells, warning signals in public domaintask, auditory stimulus

67 movement time, choice warning lights, traffic lightstask, visual stimulus

68 movement time, choice doorbells, warning signals in public domaintask, auditory stimulusbalance

69 balance, eyes open hand rails and grips in places where people might need somesupport

70 balance, eyes closed hand rails and grips in dark places where people might needsome support

sensory variables71 near-reading visual acuity labels, letters72 visual contrast sensitivity letters on products with different contrasts and under various

illumination levels73 auditory capacity telephone ring, alarm bell, door bell74 tactile form recognition, controls on audio-visual equipment

equal shapes75 tactile form recognition, controls on audio-visual equipment

different shapes76 tactile form recognition, controls on audio-visual equipment

different sizes77 tactile form recognition, controls on audio-visual equipment

different line thicknesscognitive variables

78 implicit memory programming audio-visual devices79 explicit memory PIN-codes, license plates of cars, bank accounts

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Documents

Design-relevant ergonomic data on Dutch elderly