ESSA Vol 22 1 2010

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ergonomics SAJune 2010 Vol. 22 No 1

A peer-reviewed publication of the Ergonomics Society of South Africa.

ISSN NUMBER: 10 10 2728 esa

A peer-reviewed publication of the Ergonomics Society of South Africa.

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Journal of the Ergonomics Society of South Africa

EDITORIAL BOARD

EDITOR-IN-CHIEF

CJ CHRISTIE (Rhodes University)

EDITORIAL BOARD (South African and International)

R BRIDGER (Institute of Naval Medicine, Alverstoke, U.K.) P STONE (Loughborough University of Technology)

H HENDRICK (University of Southern California) H SHAHNAVAZ (Lulea University)

PA SCOTT (Rhodes University) J WALL (University of South Alabama)

PRODUCTION COORDINATOR

J McDougall (Rhodes University)

ADVERTISING SALES

CJ Christie ([email protected] (046) 6038470)

PUBLISHING

Department of Human Kinetics and Ergonomics (for: Ergonomics Society of South

Africa)

P.O. Box 94

Rhodes University

Grahamstown

6140

[email protected]

(046) 6038468

REPRO AND PRINTING

Dupliprint (printed copies)

Department of Human Kinetics and Ergonomics (pdf copies)

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AIMS AND SCOPE

ergonomics SA (esa) provides a medium for publication of material relevant to

occupational conditions and needs in Southern Africa at a time of change unparalleled

in history. To this end the journal accepts articles in the following categories: researchpapers, review articles, conceptual theories, methodological articles involving

technology for recording and/or analysing humans at work, observational reports from

the field, brief research reports/updates, and news and views.

The editors aim to ensure that professional rigour characterises all published material

while recognising that the needs of Southern Africa in this field and of Ergonomics

anywhere, are for the generation and dissemination of technical, non technical,

fundamental and applied knowledge. To this end the journal welcomes review papers

and encourages contributions to its News and Views section.

RESEARCH PAPERS: Original empirical articles of significance for the broadly

ramified field of Ergonomics are welcomed, particularly those related to the problemsassociated with Industrially Developing Countries, particularly in a Southern African

context. These may involve original theory and/or unique application.

REVIEW ARTICLES: Review articles are encouraged and those whose focus is on

application of the contained knowledge to the situation as it pertains in Southern Africa

are most sought. The requirement of readability and appropriate writing style is

particularly crucial here.

METHODOLOGICAL REPORTS: Papers devoted to the technology for recording

and/or analysing of parameters relative to humans at work, so long as these are

presented in a form intelligible to readers representing a wide variety of professional

backgrounds, are welcomed. The requirement of clarity of exposition, particularly interms of illustrations, is particularly relevant here.

CASE STUDIES/OBSERVATIONAL RECORDS: Interesting case

studies/observations from the field, especially if they suggest problems or solutions not

previously considered, will be accepted.

RESEARCH NOTES/UPDATES: Ongoing research information which may stimulate

debate or foster contacts between professionals with similar interests may be

summarised in short (one or two page) updates. These are not subjected to formal blind

review by referees, but are published at the discretion of the Chief Editors.

NEWS AND VIEWS: Submissions for this section of the journal are personal reportsor position statements and these are encouraged in the interest of fostering debate,

stimulating thought or revision and promoting exchange of ideas. Views expressed do

not necessarily carry endorsement from the editorial board but they must be expressed

in conformity with accepted norms and standards. Contributions to News and Views are

subjected to an open review process. Letters to the Editors in Chief, engendered by

contributions appearing earlier in the journal, may be published in subsequent issues

under this section.

ergonomics SA is free to members of ESSA and may be purchased by non-members on

request from the production coordinator [email protected] or on (046) 6038468.

ISSN NUMBER: 10 10 2728

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Journal of the Ergonomics Society of South Africa.

Volume 22 (1), June 2010

CONTENTS

Editorial ............................................................................................................ 1

Ergonomic evaluation of tasks performed by female workers in the unorganized

sectors of the manual brick manufacturing units in India

S Sahu and M Sett...................................................................................................... 2

An ergonomic evaluation of workstations in small-scale cybercafes in Nigeria

S J Ojolo, S A Oke, A E Adesegha, R R Dinrifo, A Oluwo and S Orewa................... 17

Small & medium Scale Casting and Forging Industry in India: an ergonomic

Study

L P Singh, A Bhardwaj, K K Deepak and S Sahu...................................................... 36

Information for contributors................................................................................... 57

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Ergonomics SA, 2010, 22(1)

ISSN Number : 10-10-2728

1

EDITORIAL______________________________________________________________________

The euphoria of the 2010 Soccer World Cup is now over and what a world cup it was.

South Africa proved the world wrong and did itself proud congratulations to theorganizing committee and all the South Africans who made our international visitors

feel so welcome. Why, you may ask, am I bringing the Soccer World Cup into an

ergonomics journal? Well firstly, because I am a proud South African and this is a

South African journal, but secondly, because many ergonomists steer clear of sports

research considering it the realm of the sports scientist. However, there are important

links between the science of sport and the science of work. The most important being

that sport for many is their work. I would like to highlight one soccer-specific example

from a recent paper in the Journal of Sports Sciences (Reilly, 2005). Very briefly,

according to this article, as soccer is a team game, a priority in preparing players for

match-play must be to harness their individual capabilities so that the group becomes an

effective competitive unit. The paper highlights many individual and team factors thatneed to be considered (Figure 1). The model suggests that coaches (managers/engineers)

need to consider interfacing the demands of the game (tasks) with the capabilities of the

players (the workers). Thus, when preparing for competition (work), technical, tactical

and physiological requirements must be integrated in a holistic manner.

Figure 1: An ergonomics model for the analyses of football (Taken from Reilly, 2005)

Just like this model, the three papers comprising the current issue of Ergonomics SA use

the same principles of interfacing the demands of the work environment with thecapabilities of the indigenous work forces in India and Nigeria. The articles all highlight

the importance of ergonomics interventions within various industries in these

developing nations and provide important directions for future research.

Thus, the basic research premise of ergonomics and sports science is the same, just the

application differs!

Candice Christie (Editor-in-Chief)

Reilly, T., 2005. An ergonomics model of the soccer training process.Journal of Sports

Sciences, 23(6), 561-572.

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2

Ergonomic evaluation of tasks performed by female workers

in the unorganized sectors of the manual brick manufacturing

units in IndiaS Sahu M Sett

Department of Physiology

University of Kalyani

Kalyani-741235

Nadia, West Bengal,

India

[email protected]

Abstract

Manual brick manufacturing units in India, especially in the unorganized sectors,

employ a large number of female workers. In the present investigation, an attempt was

made to ergonomically evaluate the posture and the musculoskeletal disorders (MSDs)

of the female workers engaged in the brick manufacturing units. Two main types of task

are performed by the female workers in the brick fields in the unorganized sectors viz,

brick moulding and brick carrying. Modified Nordic Questionnaire and Body Part

Discomfort (BPD) scale was applied on these workers to identify the MSDs and thezones of discomfort in different body parts. Four different types of postural analyses

viz, OWAS, RULA, REBA and LUBA were done to find out the postural load of the

female workers at work. Statistical analyses showed that the zones of maximum

discomfort for the female moulders are the low back (9.31.45), followed by the calf

muscles (8.31.09), trunk (8.21.33), ankle (8.11.73), and wrist (8.01.71). On the

other hand, the maximum discomfort zones in the brick carriers are the head (9.21.63)

followed by the neck (8.81.21), trunk (8.41.61) and low back (8.21.59). Thus,

immediate ergonomic interventions are needed to prevent the MSDs by correcting the

harmful working postures and to reduce their work stress.

Key words: Manual brick manufacturing, Indian female workers, posture analysis,MSD.

1 IntroductionBrick manufacturing work is an age-old profession practised all over the world. In this

industry a lot of manual material handling (MMH) tasks are performed. In the

developed countries some mechanization was introduced but various studies show that

the workers working in the brick manufacturing units suffer from musculoskeletal

problems (Buckle and Stubbs, 1990; Ferreira and Tracy, 1991; Brogmus and Marko,

1991; Basra and Crawford, 1995; Cooket al., 1996; Heuer et al,. 1996; Chung and Kee,

2000; Trevelyan and Haslani, 2001).

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3

Notwithstanding the technological advances, a large number of workers perform heavy

MMH jobs in developing countries, especially in the unorganized sectors. Studies from

developing countries like India show that these workers suffer from assorted health

problems due to awkward postures and carrying heavy loads (Mukhopadhyay, 2008;

Sett and Sahu, 2008). All these authors concluded that musculoskeletal disorders(MSDs) resulted from frequent trunk bending, twisting and repetitive handling of

several bricks at a time. Moreover, some studies report that women have a higher

prevalence rate of work-related MSDs than that of men (Treaster and Burr, 2004; Basu

et al., 2008b).

The postures adopted by the workers in their working place depends upon the type of

work, the design of the work place, personal characteristics, the tools required to

perform the particular work and also the duration and frequency of the work cycle

(Bridger, 1995; Putz-Anderson, 1988). So, various techniques have been reported for

postural analyses to identify the stress during different phases of work (Colombini et al.,

1985).

One of the earliest methods of work posture assessment was Ovako Working postures

Assessment System (OWAS) (Karhu et al., 1977). Other authors used this method for

posture analysis (Kant et al., 1990; Kivi and Mattila, 1991; Engels et al., 1994). The

other method for postural analysis is the Rapid Upper Limb Assessment (RULA) (Mc

Atamney and Corlett, 1993). RULA has been extensively used in various studies

(Leuder, 1996; Axelsson, 1997; Gutierrez, 1998). The other two recent techniques of

work posture analysis are the Rapid Entire Body Assessment (REBA) (Hignett and

McAtamney, 2000) and Loading on the Upper Body Assessment (LUBA) (Kee and

Karwowski, 2001).

Therefore, an ergonomic study was conducted on these female workers by continuous

observation method to identify and quantify the postural stress. Moreover, the suitability

of these postural analysis methods in evaluating the working postures adopted by the

Indian female workers during different MMH tasks was under investigation. This study

also sought the prevalence of MSDs among the female brick moulders and carriers.

1.1 The brick manufacturing scenario in IndiaThe manual brick manufacturing process in India has been going on for centuries, and

millions of people are employed. A large number of female workers are engaged in this

field. In unorganized sectors, these workers are recruited temporarily on a seasonal basis

and thus are neither trained nor sufficiently experienced. Therefore, they do not haveany previous knowledge about unsafe acts and hazards related to this work, or they

simply ignore the safe working process, as also seen among the female construction

labourers of India (Basu et al., 2005; Basu et al., 2008a). MMH is the cheapest solution

in developing countries (Maiti, 2008), so most of the brick manufacturing units in India

perform the task of MMH.

The workers are recruited by employers on a seasonal basis, mainly from November to

April. These female workers come from different villages from the same or different

states of India. No work occurs during Indias monsoon season (June to August). They

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4

then go back to their villages and engage themselves in some other work, like

agriculture, basket making, etc. or remain unemployed.

There are two groups of female workers in brick manufacturing units, whose main tasks

are brick making and carrying bricks respectively. The group of female workers thatcarry raw bricks from the stacks in the field to the brick kiln and baked bricks back from

the kiln, to stack in some other places in the field are grouped as the Brick Carriers.

They work from 6:00 am to 10:30 am, take a break and again work from 2:00 pm to

6:00 pm. The other group of female workers that mix mud, carry the mud in a wooden

cart to the field, dump it and then use the mud for moulding bricks in the field are

grouped as the Brick Moulders. These female brick moulders work continuously from

6:00 am till sunset, taking intervals only while having their breakfast or lunch. Both

groups of workers work six days a week. The jobs of the two groups are not

interchangeable and they can only perform the task that is allotted to them. The workers

are paid on a contractual basis i.e. at the rate of every thousand bricks moulded or

carried.

2 Methods2.1 SubjectsThe study was conducted on 144 female workers (60 brick moulders and 84 brick

carriers) engaged in four different brick fields of West Bengal, India. Adult female

workers with at least one year of work experience were randomly chosen from different

manual brick manufacturing units in India. According to the nature of their work, they

were divided into the two groups.

2.2 Physical parametersPhysical parameters such as stature and body weight were measured with an

anthropometric rod and a weighing machine respectively. Body Mass Index (BMI) was

calculated from the anthropometric data (Poskitt, 2000).

2.3 Activity analysisWork study during actual work in the field was performed according to ILO, 1984.

Methodical studyby drawing multiple activity charts was done by Activity Sampling

method. Time studywas also done with the help of a properly calibrated stop watch.

Time taken for a particular job in each cycle and thus in each hour was observed and

noted.

2.4 Postural analysisWorking postures were evaluated directly by visual observation as well as indirectly by

a camera, and then analyzed by the following methods:

2.4.1 OWAS method(Karhu et al., 1977):Four levels of risk were identified as a function of a number of postural factors such as

the back, upper limb, lower limb postures and the degree of strength required. The four

levels of risk were then related in assessing the remedial actions: no action necessary,

action in the near future, action to be taken soon and action to be taken immediately.

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2.4.2 RULA method(McAtamney and Corlett, 1993):This was developed to assess the workers work-related upper limb disorders. For this

assessment, the postures were at first randomly selected from the freeze photographs, to

be scored as per the scoring sheet. Then the scores were put through tables that were

converted to a grand score of 1 to 7, after which they were clustered into four actionlevels.

2.4.3 REBA method(Hignett and McAtamney, 2000):The postures to be assessed were first scored and transformed into Score A and Score B

from the given table. The two scores were then entered into another table to produce the

final Score C. This result was interpreted into a table containing five action levels,

giving the risk of the assessed posture.

2.4.4 LUBA method(Kee and Karwowski, 2001):Each

joint motion class of the posture to be assessed was assigned a numerical relative

discomfort score on the basis of discomfort value, which was then categorized into four

action levels.

2.5 Nordic Questionnaire studyNordic Questionnaire (Kuorinka et al., 1987) was modified according to the situation

and was used to interview to workers in their local dialect (Bengali and Hindi). The

questionnaire emphasized their individual details, type of work and the occurrence or

frequency of pain felt in different parts of their body.

2.6 Subjective methods of discomfortThe intensity of pain or different types of discomfort was measured by utilizing theBody Part Discomfort (BPD) scale (Jacquelin et al., 1994). The scale consists of marks

from 1 to 10 and ranges from just noticeable discomfort to intolerable discomfort. A 0

in the scale means no discomfort at all.

2.7 Statistical analysisThe data were expressed as mean standard error of mean. Comparison of the means of

the Body Part Discomfort zones of different body parts in the female brick moulders

with respect to that of the female brick carriers were made by students t-test and

P

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Table 1. The physical characteristics and experience of the female workers

Height (cm) Weight (Kg) Body Mass

Index (BMI)

(Kg/m2)

Age (years) Experience

(Years)

144.15 5.67

(138-152)

40.83 4.9

(35-50)

18.43 1.33

(16.44-21.4)

22.3 3.13

(18-27)

3.2 6.25 (1-8)

(Values: Mean SEM, Figures in parentheses indicate the range)

Nutritional status of the subjects was assessed from their BMI and the mean value

showed that the subjects suffered from Chronic Energy Deficiency (CED) (Weisell,

2002). Pal et al., (2008) showed that 30% of the young tribal women engaged in brick

fields were affected by CED. The female workers working in different manual brick

manufacturing units were quite young (22.3 3.13 years)and so they had less working

experience.

3.2 Activity analysisEach activity of the workers was analysed and is represented in Table 2.

Table 2. The work and time study of the two groups of female workers

Groups Activities Load handled

(kg)

Time taken (sec)/

Cycle

No. of cycles/

Hour

Brick moulding

(6.9 .45 mins/

Cycle)

Mixing mud once

with hand

Carrying mud by

pushing a woodencart

Cutting mud for 1

brick

Squat and mould

1 brick

Take out 1 brick

from mould

23.26 2.01

37.76 2.95

5.85 .25

6.07 .31

5.37 .39

14.55 3.67

34.65 1.31

3.46 .55

9.50 1.33

3.95 .67

11.41 .67

9.57 .45

76.28 .9

68.33 .37

80.12 .33

Brick carrying

(9.37 1.13

mins/trip)

Stack 1 brick onhead

Stand with 12

bricks on head

Walk with bricks

on head

Unload 1 brick

and place on the

kiln top

49.61 .55

50.05 .69

50.31 1.01

30.25 4.14

10.62 2.25

5.29 3.19

66.23 3.67

11.07 1.33

23.67 .17

45.03 .79

7.45 .28

25.13 .55

(Values: Mean SEM)

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The tasks of the brick moulders are completed within a cycle time of 6.9 .45 mins.

Thus they complete about eight such cycles in one hour. The time taken (sec) to mould

one brick has been depicted in the table. Altogether they mould 8-10 bricks in 3.88 .7

min with the mud that they carry at one time, in the wooden cart. On the other hand, the

brick carriers complete one whole cycle in 9.37 1.13 min and the female workerscarry 10 to 12 bricks at a time.

From Table 2 it can be concluded that for cutting mud and moulding, the cycle time is

much less. These tasks are described as repetitive as they perform more cycles per hour,

so the brick moulders are put under stress. On the other hand, maximum time is spent by

the brick carriers walking a distance (.6 .13 Km) to and from the field and brick kiln,

with load (50.31 1.01 kg) or without load respectively. Each unbaked brick weighs

about 4.5-5.0 kg and each baked brick weighs about 3.5-4.0 kg. They carry 10-12 bricks

at a time. They are paid per thousand bricks carried, so even if they get exhausted, they

carry on with their task, which further puts the brick carriers under stress.

3.3 Postural analysis

A. B.

C. D.

Figure 1. Photographs of the female workers engaged in different activities in the

brick field: - (A) Carrying mud in a wooden cart, (B) Moulding mud, (C)

Stacking bricks on head, (D) Walking with bricks on head to the brick

kiln

In Table 3, the postural analysis of the different steps in brick moulding performed by

the female workers is represented in detail, along with the maximum discomfort zone

and rating. The different tasks done by the female workers while moulding bricks are:

mixing mud by hand, carrying mud by pushing a small wooden cart, cutting mud,

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squatting to mould, and finally taking out a brick from the mould. These tasks have

been designated as a, b, c, d and e respectivelyfor convenience in discussion.

According to the known four types of postural assessment, the risk level of postures a, c

and d have been categorized from High to Very high and these postures needimmediate corrective measures in the near future. But there are some disparities among

the results obtained from the four methods of postural analysis in postures b and e.

According to OWAS and LUBA methods, posture b is not harmful, unlike the results

obtained from REBA and RULA methods. Again, OWAS analysis of posture e is

categorized as having some risk but the others define it to be very risky. As per the

maximum discomfort rating, the posture adopted in e is marked as intolerably strenuous

(9.1 .33) by the female moulders.

Hignett and McAtamney (2006) stated that RULA is generally used if the person is

sitting, standing still or in an otherwise sedentary position, and mainly using the upper

body and arms to work. For all other tasks REBA should be used. On the other hand,Kee and Karwowski (2006) indicated that the LUBA technique is applied to the seated

or standing postures, with the lower limb well supported in an evenly balanced posture.

OWAS postural analyses have been worked out on a wide range of postures, from

bricklaying (Kivi and Mattila, 1991) to nurses (Engels et al., 1994) to the workers in

garages (Kant et al., 1990) but the results can be low in detail (Hignett and McAtamney,

2000). So, a suitable method is required for evaluating the postures adopted by workers

squatted on the ground (Fig 1. B), in the Indian context.

In Table 4 the total postural analysis of the sequential steps in brick carrying is

represented in detail, along with the maximum discomfort zone and rating. The different

tasks done by the female workers while carrying bricks are: stacking bricks on head,standing with bricks on head, walking with bricks on head, and finally unloading bricks

on the kiln top. They have been designated as f, g, h and i for convenience in

discussion.

Postures fand h are categorized as having medium to high risk level as per all the

types of postural assessment. The results obtained from LUBA and RULA methods are

same for posture g and this is the correct method for assessing such postures. These

methods are used in postures when an individual is sitting or standing still with lower

limbs well supported and the upper body is at work. Moreover, the maximum

discomfort rating is in the head (8.9 .67) because the carriers carry heavy loads. There

are differences in these results from that of the OWAS method, which marks posture i tobe harmful. So, OWAS, REBA, RULA and LUBA methods do not evaluate the half

squat posture adopted by the workers during this task.

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Table 3. Different methods of postural analysis of the female brick moulder

Posture Activities OWAS

code

Risk

(OWAS)

RULA

score

Action

level

(RULA)

REBA

score

Risk

level

(REBA)

LUBA

postural

load

Actio

categ

(LUB

a

Mixing

mud by

hand

2, 1, 3, 3 Major

strain

7 4 10 High 15 IV

b

Carrying

mud bypushing a

wooden

cart

2, 1, 6, 3 Not

harmful

7 4 9 High 8 II

c

Cutting

mud

2, 1, 3, 2 Major

strain

7 4 11,12 Very

High,

12 III

d

Squat and

mould

2, 1, 3, 1 Some

strain

7 4 10 High 13 III

e

Take outbrick from

mould

4, 1, 3, 1 Some

strain

7 4 13 Very

High

16 IV

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Table 4. Different methods of postural analysis of the female brick carrier

Posture Activities OWAS

code

Risk

(OWAS)

RULA

score

Action

level

(RULA)

REBA

score

Risk

level

(REBA)

LUBA

postural

load

Action

category

(LUBA)

f

Stack

bricks on

head

1, 3, 3,

3

Some

strain

4,6 2,3 6,9 Medium,

High

10 III

g

Stand

with

bricks on

head

1, 3, 1,

3

Some

strain

7 4 9 High 15 IV

h

Walkwith

bricks on

head

1, 3, 6,3

Somestrain

5 3 9 High 10 III

i

Unload

bricks on

the kiln

top

2, 2, 3,

3

Harmful 6,7 3,4 7,9 Medium,

High

7,13 II,III

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3.4 Discomfort and pain in different body partsFigure 2 shows the graphical representation of pain in different parts of the body of two

groups of the female workers, according to the modified Nordic Questionnaire.

0

20

40

60

80

100

120

Head

Neck

Shoulde

rElbo

w

Uppera

rm

Lowe

rarm

Wrist

Hand

Trun

k

Lowba

ckTh

igh Knee Fe

etAn

kle Calf

Leg

Different body parts

Complaints(%

)

Brick moulders

(N=60)

Brick carriers

(N=84)

Figure 2. Complaints about pain (in percentage) in different parts of the body of

two groups of female workers

From the graph it is clear that the brick moulders have more pain in the low back andpart of the legs because most of the time they sit continuously in the same awkward

posture to mould the bricks. On the other hand, since the female brick carriers carry a

heavy load to and from the field and the brick kiln, they suffer more discomfort and

pain in the head, neck, shoulder and also their trunk. Musculoskeletal pain is not felt by

the workers before work or at work. 38.89 % of the female workers feel severe pain just

after their whole days work, i.e. in the evening. Others feel pain in their different body

parts when they go to sleep at night and take rest.

The intensity of pain or discomfort was measured by utilizing the Body Part Discomfort

(BPD) scale, which is depicted by graphical presentation in Figure 3.

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12

0

2

4

6

8

10

12

Head NeckSh

oulderEl

bow

Upperarm

Lowe

rarmWrist HandTrunk

LowbackTh

igh Knee Feet Ankle Calf

Different body parts

BodyPartDiscomfortSc

ale

Brick moulders (N=60)

Brick carriers (N=84)

Figure 3. Graphical presentation of the different discomfort zones of the body, as

per the Body Part Discomfort (BPD) scale of the two groups of female

workers

From the above graphical representation it is clear that more discomfort zones are

concentrated in the upper part of the body of the female brick carriers, such as the head,

neck, shoulders, arms etc. than that of the lower body parts, as seen in the case of

female brick moulders (P

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Among the types of discomfort, it was noticed that the female workers of both groups

felt pain in different body parts. The percentage of pain is higher (90.48%) in the case of

the female brick carriers. However, as the socio-economic conditions of the workers are

very poor, so to earn more they carry more bricks even if they get exhausted. The

percentage of swelling and stiffness is lower but cannot remain unnoticed.

From the study, it is recommended that redesigning the workplace and rescheduling the

work-rest cycles of these female workers, along with proper counselling of food habits

and maintaining hygienic conditions, is necessary to upgrade their quality of life. An

ergonomically designed sitting stool is suggested for the brick moulders and assistive

load carrying or carrying bricks loaded on a cart would reduce the workers work load

in the work place.

4 ConclusionAccording to the OWAS and REBA methods, the postures adopted by the brickmoulders have been categorized as having High to Very high risk levels and that of

the postures adopted by the brick carriers have Medium to High risk levels, even

though complaints about the different discomfort feelings are more prevalent among the

carriers. The results are supported by the subjective assessment of discomfort. The

female workers rise before dawn to finish off their household chores and cooking before

they move off to the brick fields, which altogether puts them under stress. Thus OWAS

and REBA methods of postural analysis closely correlate with the awkward postures

adopted by the female workers. Though REBA method is used for sitting postures, a

new method of postural analysis needs to be developed in the future for assessing the

postures of being seated on the ground, as in the Indian context.

Moreover, ergonomic interventions such as redesigning the workplace and the work-rest

schedule would improve the conditions of the female workers and reduce their work

stress.

Acknowledgement

The authors express their sincere gratitude to all those female workers and the

employers from the different brick manufacturing units, who rendered immense co-

operation for the completion of this study.

References

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improvements. In Seppala, P., Luopajarvi, T., Nygard, C. H. and Mattila, M. (Eds):

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An ergonomic evaluation of workstations in small-scale

cybercafes in Nigeria

S J Ojolo, S A Oke,

A E Adesegha

Department of Mechanical

Engineering

University of Lagos,

Lagos, Nigeria

[email protected]

R R Dinrifo

School of Engineering

Lagos State Polytechnic

Ikorodu, Lagos, Nigeria

A Oluwo, S Orewa

Department of Mechanical

Engineering

University of Lagos,

Lagos, Nigeria

Abstract

This paper presents a survey of cybercafes in a developing country to reveal their

design pitfalls and propose appropriate solutions to the observed problems based on

ergonomic principles. These cybercafes provide Internet services to communities but

the concern is to make the work convenient at the computer workplace and comfortable

at work thus reducing the risk of musculoskeletal injury and minimising energy

expended at work. A survey was conducted in fourteen cybercafes using questionnaires,

personal interviews and actual field measurements. Ergonomic analysis revealed that

cybercafe chairs are the major pitfalls of the caf design: they are often too short with

no arm rests and with insufficient backrests. Chairs are also stationary as opposed to

being mobile with rollers. Customers leg positioning under the table is restricted and

the workspace is too small. Also, the top of computer monitors often is above eye level

for an average height customer. Since very little documentation exists on the subject in

developing countries, the work opens a gate of opportunities for those in the cybercaf

business with financial constraints to implement standard designs. The work also

complements the dearth of expertise in the area since many towns in Nigeria do not

have the required expertise for cybercaf design and construction.

Keywords: Cybercafe, ergonomics, survey, developing country, Nigeria, ergonomic

evaluation, ergonomic design

1

IntroductionThe Internet has influenced the world today by providing adequate, up-to-date

information useful for research and decision making (Ahiabenu, 2002). Since only a

small fraction of Internet users in Nigeria could afford personal Internet connectivity in

their homes and offices, others utilise commercial service outlets referred to as

cybercafs. A cybercaf is a room, an office, or a social accommodation with computer

terminals connected to a server and established for profit making by selling user time.

Apart from Internet browsing and multimedia services provided by cybercafs, Internet

calls, printing, scanning, fax, online chatting, communicating with each other by

transferring computer files, searching databases, exchanging electronic mails,

conferencing, downloading and CD-ROM burning are other services also provided. On

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university campuses in Nigeria, numerous students also patronize cybercafs to obtain

information on personal updates on global issues, articles, social and academic events,

data, news, projects, political issues, international contacts, commercial information and

online-transactions, travel, entertainment, and information on software and hardware.

The computer operator/user at a cybercaf undergoes a variety of muscular stresses

while working for long durations which degrades the quality of work. This situation is

similar to the case described by Parmod et al., (2006) and is well supported by Helander

(2003). Thus, the proper design of cybercaf workstations will ensure ease of

functioning for the operator/user without experiencing stress on vital body parts. In this

paper, it is emphasized that there is lack of documentation in the Nigerian environment,

which means a lack of research on cybercafs and a lack of anthropometric data. It is

observed that many new cybercafs are designed based on the intuitive knowledge of

the project team leader. However, once a particular pattern of design has been adopted

and money is spent on the project, it becomes wasteful to redesign the cybercaf when

such waste could have been avoided at the design stage. Take for instance, a design witha chair too low in height (see Finlay et al., 1983; Cram and Vinitzky, 1995). A user who

sits on this inconvenient chair for two hours or more would prefer to terminate the work

at that point due to reactions on his or her buttocks. Also, too high tables would not

permit easy browsing and writing out of information on the table. However, if standard

guides are available for cybercafs, the project team leader would benefit from the

research to design an ergonomic cybercaf. The sparse and unavailability of

anthropometric data on cybercafs for the West African population has therefore wasted

resource utilization in this sector of the economy.

The design of basic computer workstations might be different to that of a cybercaf in

many respects. For instance, two different design types are common in the Nigerianenvironment. A group of cybercaf workstations considers standardised chairs thatprovide standardised height, pan-width, backrest-width and backrest-height. The other

group utilizes highly adjustable chairs for allowing many different people to use the

same equipment. However, adjustable chairs are very expensive and wear out too often

making it only affordable to a selected few cybercafs. These sitting characteristics are

essential to maintain adequate eye level, buttock comfort, and to minimise pains due to

backrest discomfort. However, for other workplaces such as the telephone operators

workstation, supermarket counter, and receptionist in an office environment, such

highly detailed standardised specifications are also required and have been extensively

documented (Carter and Banister, 1994; Liao and Drury, 2000) However, such studies

do not provide the full details to understand the case of cybercafes. The standardised

chairs required for cybercafes are supposed to take care of the nature and period of

transactions of customers. Also, cybercafs customers spend a short to medium term

period and would need seat designs that may permit only minimum back muscle fatigue

(see also Goldstein, 1978; Lane and Stewart, 1980; Mehta and Tewari, 2000; Mehta et

al., 2008). If customers are uncomfortable with their seating posture and position, they

would just leave and take their custom elsewhere.

The Nigerian situation is unique in the sense that the culture is different from that of

other developed nations. Nigerians embrace the culture of togetherness and working in a

group even with students in tertiary institutions. Take for instance in a cybercafe,

although only one user at a time (say one hour computer time) is sold to an

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undergraduate, several people may utilize this computer time at achieving a common

goal at the same time. Therefore, if the student gets the required information from the

internet despite his poor knowledge of computer and internet usage, it may be

convenient for him to go with a crowd to the cybercafe. This case is common because of

the low level of computer education of most cybercafe users. Therefore, a crowd mayeventually use the space created for a single user. This is possibly a unique situation in

an industrially developing country (Nigeria) and the associated problems call for an

investigation on the design of cybercafes in this country.

As discussed later in this article, although it is agreed that some information relating to

important aspects of computer workstation design and anthropometric measurements

may be available in the literature, they provide very little guidance for research and

decision making for developing countries, especially within the Nigerian context.

Unfortunately, anthropometric data are not available for the Nigerian population. For

example, cybercafs in a developing world context (Nigeria) might be different to more

industrialized countries when considering a number of things, which include pooraccess to Internet in homes. Human traffic in cybercafs in Nigeria is very high such

that the cybercafs owners make the most economic use of space. The luxury of space

allowance between the sitting positions of customers in cybercafs in Nigeria may not

be affordable while this could be permitted in industrialized countries with fewer people

utilizing cybercafs. In addition, the strict business laws restraining cybercaf operators

from inadequate design are not enforced in Nigeria. The uniqueness of the situation of

an industrially developing country (Nigeria) and the associated problems gives

justification for building up a new set of computer workstation design data.

2 Literature reviewThe literature reviewed here scrutinizes previous work relating to workstation design

how this could benefit the cybercaf workstation design. A series of papers have

reported on wrist postures and problems in keyboard typing (Chen et al., 1994; Hedge

and Powers, 1995; Hedge and Shew, 1996; Bash and Rempel, 1997). Some other papers

have reported on video display terminals (Hunting, 1991; Grandjean, 1993). Helander

(2003) surveyed indicators of ergonomics quality by using parameters that relate to

aesthetics and comfort and long-term ergonomics factors that depend on feedback from

ligaments, joints and the spine (see also Paul and Menon, 1994; Parsons, 1991; Radwin,

1994; Snook, 1993). Several other ergonomics considerations have been made that

could improve the quality of service in cybercafs (Hedge, 1994; Human and Rempel,

1995). The ideas for workstations developed by Shikdar and Al-Hadhrami (2007) could

be applied to cybercafes. The workstations special features include a motorized table

for upward, downward and angular movements, an ergonomic chair with an adjustable

seat pan, arm support and back support. Cost consideration and affordability are also

important considerations arising from the presentations of Mandal (1995) and Oborne

(1995). The workstation could be used as a sit, stand or sit-stand workstation. From

experience and knowledge of field visits, it seems that many parts of the cybercaf

workstations could be improved with knowledge of the literature. Thus, efforts at

improving the following would significantly improve performance at cybercaf

workstations: (1) seat/chair design (Hatta et al., 2007), (2) table/desk design, (3) indoor

air quality, and illumination levels, (4) noise levels, and more.

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2.1 Seat designThe design of seats (including chairs) has been a major concern of a growing number of

investigators, who aim at providing a comfortable position for the operator in order to

guarantee optimum work performance and avoid accidents in work involving mobility.

Goonetilleke and Feizhou (2001) argued that anthropometry alone is not sufficient for

the design of seats. They argued that the differing sensitivity in the buttock and thigh

areas is an indication that chairs should be designed and selected depending on the

population under consideration. Their paper developed a methodology to evaluate the

useful seat depth for a target population. This information may be usefully adapted for

cybercafe workstation design, particularly for the various cybercafe chair designs shown

in Figures 1 to 4. Vos et al. (2006) investigated postural and chair design impacts upon

seat pan interface pressure in order to identify whether differences in posture or chair

design result in greater pressure differences. The trunk-thigh angle may, in a practical

sense, be greater than 900

since the trunk, thigh and the back have to be positioned in a

relaxed position, which is aided by an angle greater than 900. Also, the use of an armrestsignificantly reduces energy losses since the user could comfortably relax their hand on

the armrest instead of leaving it in a swinging position that consumes energy

unnecessarily. Nag et al. (2008) analyzed the human-seat interfaces to determine the

differential distribution of the body weight on the components of the seat. The study

stated that the horizontal as well as a 5 forward slope of the seat is the preferred choice,

since the load distributed at the seat was highest at the backward sloping seat for all

conditions of the supported and unsupported back. The study also reaffirms that the

backrest and armrest have a conjoint influence in reducing the load distributed at the

seat, which in turn might help in mitigating stress on the spinal and other paraspinal

structures.

2.2 Workplace layout and Visual Display UnitsWorkplace layout, which deals with how equipment and furniture are positioned to fit

the individual operator to allow good and flexible work postures, has been extensively

applied to different work settings (ISO, 1999; Toomingas and Gavhed, 2008).

Toomingas and Gavhed (2008) studied the workstation layout at call centres in Sweden

and concluded that the quality of furniture was generally good and fulfilled the demands

of the law, directives and standards. This study is not much applicable to the current

investigation in view of the different settings that the studies focus on: one focuses on

the call centre while the current study directs attention to cybercafs. These are different

services, different work posture requirements and different commitment requirementsfrom operators in terms of customer satisfaction and well-being. Thus, previous

literature is lacking in sufficient details to assist in carrying out the current study.

Lindegard et al. (2005) published data sets on workplace layout by expert ergonomists

and concluded that ratings of comfort and perceived exertion could be used as cost-

efficient and user-friendly methods for practitioners to identify high exposure to poor

workplace layout. However, Hutchinson (2008) criticized the conclusion and stated that

users and experts ratings were very largely independent of each other.

Several studies have established a relationship between musculoskeletal disorders and

the use of video display units (VDU) (e.g. Nevala-Puranen et al., 2003; Carter and

Banister, 1994; Faucett and Rempel, 1994). However, very sparse information concerns

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its relationship with table dimensions, particularly for less developed societies. A

prominent result reported by Nevala-Puranen et al. (2003) showed that repeated neck,

shoulder and arm symptoms can be more efficiently reduced among newspaper

employees if ergonomic measures are combined with changes in work techniques than

if the redesign measures focuses only on the work environment. Additional studies onVDU include (i) interventions for reducing complaints on VDU while working

(Pillastrini et al., 2007); and (ii) incidence of neck pain among office employees

working with video display units (Korhomen et al., 2003) which reported that annual

incidence of neck pain was 34.4% and that the poor physical work environment and

poor placement of the keyboard increased the risk of neck pain in office employees.

From the above review, unfortunately, the ergonomics design of cybercafs particularly

in a developing country context is completely omitted. Thus, there is currently a great

need for an article presenting a viewpoint of the application of ergonomics to the design

of chairs and workstation facilities in cybercafes particularly in developing countries.

This will ensure that the customer works comfortably and utilizes the computer facilitiesoptimally with minimum loss of energy and full interest at work. In particular, the

objectives of this paper are to present a survey of cybercafes in Nigeria to reveal design

pitfalls and propose solutions based on ergonomic principles. The challenge is to

capture the various ergonomic features of cybercafe design in a quantitative way, as far

as reasonably possible, and display the distilled results.

3 Methodology3.1 SampleThe participants in this study were mainly university students, some secondary school

students and a large number of young post-secondary school graduates which are in the

working class group whose activities are almost daily on the utilization of computers for

browsing at the cybercafes. These cybercafes are concentrated around the two university

campuses University of Ibadan and University of Lagos where data were collected.

This study was carried out on the few operators that render services to customers daily,

particularly those who volunteered to provide useful data for this study. The study took

the anthropometric data of 100 respondents which include 55 males and 45 females.

Please note that information concerning 5 other respondents could not be obtained due

to the non cooperation of the respondents. Although no biographical information such

as ethnic background was documented, experience revealed that the majority of the

respondents belonged to the Yoruba and Igbo ethnic groups while the Hausa ethnicgroup members covered by the study were insignificant. Additional information on the

demographic characteristics of the people interviewed would have been useful but could

not be collected for the current work in view of the reluctance of the respondents to

provide all the information required.

Concerning the anthropometric data of the subjects, it was discovered that the average

age of the subjects studied was 28.04 5.28 years. It was interesting to note that 29% of

the sampled group was in the age bracket 20-23 years, which formed the highest

proportion and confirmed that the focus group was largely university students, many of

whom were undergraduates in this age bracket. The remaining composition of the study

group was 26% (24-27 years), 15% (28-31years), 12% (32-35 years), 13% (36-39 years)

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and 5% (40-43 years). The average shoulder-to-shoulder length of the subject was 46.20

4.51cm. The average arm length was 77.20 5.14 cm while the average shoulder

height from waist was 47.90 4.06cm. The average finger length was 9.36 1.23 cm

while the average body height from ground was 172.10 7.85 cm.

3.2 Procedures and instrumentsThe study was carried out for eight weeks while five days per week was used for data

collection and the other days for planning and analysis of the data. Fourteen cybercafs

were visited where questionnaire and facility layout analysis were done. Efforts were

made to capture as much information as possible, hence, the use of three methods of

data collection: questionnaire, personal interviews and field data collection. A total of

120 questionnaires were administered to staff and customers of the 14 cybercafs while

105 questionnaires were returned. Some information concerning the extra four

cybercafs which made up to 14 were not obtained. Subsequently, we reported

extensive information for only 10 cybercafs. The results from the questionnaires have

been reported in the results section. Personal interviews were conducted with staff and

customers of the cybercafes to support the responses obtained from the questionnaire

method. Ten (five staff operator/cybercafe attendants and five customers) separate

interviews were conducted due to the limitations imposed by the interviewees unwilling

to spend time with the interviewer. However, it was recognized that the cybercafe

attendants/operators have a rich experience on the problems encountered by the

customers in the cybercafes and would distill out the useful parts of these problems to

the interviewer. On the other hand, it was known that first hand information would be

obtained from the customers relevant to the problems being encountered while working

at the cybercafs. Some of the staff and customers were reluctant in documenting their

views, while others were prepared to release information verbally. Personal interviewswere extensively adopted in the data collection process to make up for the shortcoming

of the questionnaire method.

Subjects completed a series of self-report questionnaires that asked for a variety of

information. Separate questionnaires that contain the same questions were administered

to men and women. The separation was for ease of categorizing the different data by sex

of respondents. The questionnaires were designed to capture both the features of the

cybercafes that were important to customers and the effects of utilizing a cybercafe that

were at variance with standards which can inflict injuries and pain on the users. Section

A contained questions relevant to the adequacy or otherwise of chair height, coverage of

chair by foam and leather, height of the computer table, inhalation of fumes fromgenerators, and comfort of the customer in terms of space availability for the activities

that the customer intends to perform. The focus of section B was to understand the

effect of the cybercafe on the customer in terms of eyestrain, headache symptoms and

musculo-skeletal strain. The assumption made in developing section B was that the

side-effects of utilizing the cybercafe were immediately felt by the user and were

directly reflected in the reactions of these customers to such effects. As an extension of

section B, respondents were asked to rate (on a scale 1 to 10) the following according to

the extent to which they are affected when working on the computer: ache, pain,

discomfort. Ache and pains are states of discomfort. Pains could be felt in the body

through the stress or strain on the nerves and veins. It may also evolve as a result of

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enormous computer activities carried out incessantly. Discomfort is a persistent state or

condition which emanates as a result of the first two.

In order to capture the range of monitor viewing distances that would permit proper

viewing of letters on the monitor without any complaints by the user, a strategy of datacapture in two phases was undertaken. The first phase entailed starting from the

minimum monitor viewing distance and then gradually moving in increments of 10cm,

taking note of the complaints of eye ache, heavy eyes and where the user barely sees

letters displayed on screen. In-between these two extremes is a region where slight

eye ache was felt. This particular region of slight eye ache is then thoroughly

investigated by segmenting the viewing distance into smaller bits. This was done as part

of phase 2.

3.3 MeasurementsActual measurements were made of the various facilities utilized, and comparative

analyses were made with the literature values. Measurements that were collectedincluded body height, shoulder-to-shoulder length, arm length, shoulder height from

waist, and finger length.

Subjects (the 100 people who completed the questionnaires) were tested individually at

their workstations. Workstation dimensions were measured while they were sitting in

front of the computer. Monitor distance was observed; this was the distance from the

centre of the monitor to the eyes when sitting in front of the computer with fingers on

the home row key(s) as well as the viewing angle of the operator from the monitor. The

procedure for measuring the viewing distance of the sampled subjects at the cybercafe

involved observing the viewing distance of the 100 subjects from their monitors in the

range 30 cm to 130 cm from the centre of the monitor using a gradual increment of10cm to 1cm. The viewing angles of subjects were measured while actively working on

the computer. In order to obtain the optimum viewing angle, the 100 subjects had their

monitors tilted in steps of 50

from 150

to 600

and the resulting complaints of the subjects

noted.

A description of the measuring instruments that were used to collect the anthropometric

data is as follows. A measuring tape, which is a flexible form of ruler of a ribbon of

cloth with linear-measurement markings was used to measure distances and lengths of

chairs/desks, body sizes and measurement involving linear dimensions. Due to its

flexibility that allows for a measure of great length, it was easily carried about. Its

length was 300 cm. A second measuring instrument used for the study was a protractor,which aided the measurement of a set of angles, particularly when the viewing angles

and distances of the various respondents from points of reference were to be

determined. In particular, it was used to measure various angles that the respondents

were positioned in a viewing posture.

4 ResultsDuring the survey, various designs of chairs were observed (Figures 1-4), which have

different features. The approach utilized in presenting results provided information that

reported on the following (a) range (maximum and minimum value), (b) the average, (c)

the standard deviation for each of the following major chair dimensions across all the

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chairs/cybercafes height from floor to top of backrest, height from floor to seat pan,

seat pan width, seat pan depth, height from seat pan to top of backrest, backrest width.

Figure 1. Partial view of Cybercafe XY

Figure 2. Partial view of Cybercafe XYA

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Figure 3. Partial view of Cybercafe XYB

Figure 4. Partial view of Cybercafe XYC

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In sum, eight different chairs were analysed and reported in the survey (Table 1).

Similar to the measurements done on different chair types, information for major table

dimensions was obtained and presented in Table 2. In fact two different table types were

captured during the survey.

Table 1. Anthropometric measurements of Chairs

S/No. Description Mean values

(_

x ) cm

Range (R) (minimum

to maximum) cm

Standard deviation

() cm

1. Height from floor

to top of backrest

88.56 69.00 125.00 29.23

2. Height from floor

to seat pan

43.81 41.50 45.50 2.14

3. Seat pan width 41.00 35.00 47.50 14.21

4. Seat pan depth 1.44 1.00 4.50 0.155. Height from seat

pan to top backrest

49.06 34.50 80.00 19.02

6. Backrest width 44.12 25.00 56.00 43.81Number of chair types = 8 (sample size)

Table 2. Anthropmetric measurements of Tables

S/No. Description Mean values in cm Range (R)

cm

Standard

deviation in cm

1 Table height from floorto table top 80.61 58.60-104.90 12.27

2 Table width 62.16 40.90-95.50 15.32

3 Table breadth 179.84 81.80-327.00 81.83

4 Side boarding height 26.28 5.16-8.18 3.32Number of table types = 2

Side boarding is a partition that separates one user from the other while they are using

the same table. Data on the monitor distance and monitor angle were also analysed and

presented here (Tables 3 and 4). Information relevant to (a) range (maximum and

minimum value), (b) the average and, (c) the standard deviation are explored. The otherdata is presented on the viewing angle of people (Table 5). Measurements were taken in

two phases 1 and 2.

Notice that complaints by subjects fall in a range but in certain cybercafs the complaint

is the same. This means that there may be a systemic problem, possibly poor work

design that positions the operator in a way not to observe the displayed information

properly due to space management problems.

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Table 3. Monitor view distance (cm) (phase 1)

Cybercafe Range (cm )

(minimum-

maximum)

Midpoint

(cm)

Average complaint by the 10 subjects

in each cybercafe

1 31.00-39.00 34.50 Eye ache, heavy eyes

2 40.00-49.00 44.50 Slight eye ache

3 50.00-59.00 54.50 Slight eye ache

4 60.00-69.00 64.50 Slight eye ache

5 70.00-79.00 74.50 Eyes strain

6 80.00-89.00 84.50 Eyes strain

7 90.00-99.00 94.50 Barely sees letters displayed on screen



10 120.00-129.00 124.50 Barely sees letters displayed on screenNumber of subjects per cybercafe = 10; this number is taken because of the limitation in data collection.

Generally, there was a difficulty encountered in the collection of data on viewing

distances of users from the monitor. The cybercafe owners and operators viewed the

survey exercise as a distraction to their operations since measurement attempts entailed

moving close to the customer at work and thus forfeiting customers privacy which is

held in high esteem by the operators. Thus, to achieve the aim of this measurement

exercise, a strategy of spending the least possible time in the cybercafe while optimally

utilizing time in measurement was explored. The investigators were constrained to split

the viewing distances measured in each cybercafe across a number of cybercaf outlets

surveyed. We embarked on this strategy as it promoted randomization of measurement.

However, we suggest that future studies should tackle this problem by taking complete

measurements at each cybercaf.

Data concerning the letters displayed on the screen is relevant to the work the user is

doing at the particular time the investigation was carried out.

Table 4. Monitor viewing distance (cm ) (phase 2)

Cybercafe Range (cm )

(minimum-maximum)

Midpoint

(cm )

Average

complaint by the

10 subjects in

each cybercafe1 50.00-59.00 54.50 No complaints

2 60.00-69.00 64.50 No complaints

3 50.00-59.00 54.50 No complaints

4 60.00-69.00 64.50 No complaints

5 50.00-59.00 54.50 No complaints

6 60.00-69.00 64.50 No complaints

7 50.00-59.00 54.50 No complaints

8 60.00-69.00 64.50 No complaints

9 50.00-59.00 54.50 No complaints

10 60.00-69.00 64.50 No complaints

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Number of subjects per cybercafe = 10. Notice that the standard deviation is about 9 for

all the cybercafs in both phase 1 and phase 2.

The decision as to which cyber caf was given 50-59cm and which was given 60-69cm

was made randomly as a result of the constraint on data collection in cyber cafes. It isthought that a good representation of the data collection could be made if smaller ranges

of values of viewing distances were spread across all the cyber cafs. Phase 2 was

carried out with a focus on the possible distance in which the customer experienced the

least discomfort.

Table 5. Viewing angle of people (degrees)

No of subjects

(people)

Mean viewing

angle (degree )

Comments from subjects

1-10 15 Slight neck pain

11-20 20 No visibility of letters on screen21-30 25 Little changes in visibility of letters on screen

31-40 30 No pains at least for a period of 6 hrs



61-70 45 Slight neck pains

71-80 50 No visibility of letters on screen

81-90 55 Little changes in visibility of letters on screen

91-100 60 Heavy neck painsSample size = 100. Subjects in 10 cybercafes. Note standard deviation is zero for all entries

It was noted that very little information existed on the statistics presented here. Whenmore than 50% of the class members comment on a complaint, the same is taken as

representative of the group. For instance, more than 50% of the subjects in the mean

viewing angle of the 150

category complained of slight neck pain. This is taken as

representative of the group. From field experiments, the majority of people who utilized

an extensive period working on the computer usually engaged in about 6 hours of work.

For ease of reference and classification, 6 hours was used as a point within which the

effects of using the computer were measured. Other results of anthropometric data of

cybercafe users presented in this section relate to means and standard deviations of

actual measures of subjects including anthropometric features such as shoulder-to-

shoulder, arm length, shoulder height from waist, finger length and height of subjects,

This, aided by the tape rule measurements, presents an idea of anthropometric features

of the sampled population. The data are shown in Table 6.

As indicated in the method section for the measurement of viewing distance of sampled

subjects, for the range 31cm to 39cm, the subjects complained of eye ache and heavy

eyes. However, in the viewing distance of the range 40cm to 49cm, the subjects were

fairly comfortable and only complained of slight eye ache. For high and low tables and

chairs, although the viewing distance may not be much affected, however, the tilting

angle would change. In the range 50cm to 59cm, the complaint by subjects was still

limited to slight eye ache. The same complaint was repeated for the range 60cm to

69cm. However, when the viewing distance of 70cm to 80cm was observed, the

complaint was persistent eyestrain instead of the slight nature of eye ache from 50cm

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upwards. It was suggested that 50cm and 70cm were the turning points, representing a

possible range of values to further investigate in order to obtain the optimum viewing

distance of computer users in cybercafes for the group presented in this work. Further,

in the range 80cm to 89cm, the subjects still complained of eyestrain. In the range 90cm

to 99cm, the subjects could barely see the letters displayed on the screen. However, inthe ranges 100cm to 109cm, 110cm to 119cm, and 120cm to 129cm, the complaint by

the subjects was uniform, which stated that they could no longer see letters displayed

except the light from the screen. The phase 2 of the work made use of repeated

procedures for determining the appropriate viewing distance but focusing on the ranges

50cm to 59cm and 60cm to 69cm. It was observed that none of the 100 subjects

complained within these ranges.

From the survey, both the average table height and chair heights were in the range

52cm80cm and 40cm60cm, respectively. The seating (chair) height of 53.3 9.14 cm

fell within the boundary of the range obtained by Shikdar and Al-Hadhrami (2007),

which indicates a seating chair height of 43-56cm. However, the upper boundary maybe exceeded. The table height obtained fell within the literature value of Shikdar and

Al-Hadhrami (2007), which showed table height of 70-105cm (from field experience).

This was slightly different from XYC as shown in Figure 4.

Table 6. Anthropometric features of subjects

S/No. Description Mean values for

subjects (_

x )

Standard

deviation

for subjects ()

Range (i.e.

minimum and

maximum)

1. Age 28.04 yrs 5.28 yrs 20.00 40.00 yrs

2. Shoulder-to-shoulder 46.20cm 4.51 cm 37.00 52.00cm

3. Arm length 77.20cm 5.14cm 66.00 84.00cm

4. Shoulder height from

waist

47.90cm 4.06cm 20.00 54.00cm

5. Finger length 9.36cm 1.23cm 8.00 12.00cm

6. Height 172.10cm 7.85cm 161.00 183.00cm

5 DiscussionMost of the pitfalls of the cybercafe design were due to the poor design of cybercafe

chairs. In the following highlighted points, a set of recommendations are made, which

emerged from the study comparing the anthropometrics of the users to the dimensions

of the desk/chair, as shown in points 1 to 5 and point 7. However, point 6 emerged from

the literature. (1) The height of the chair was too low (see Table 1, where the height

from the floor to seat pan is 43.81 cm). It was not convenient for short people in that

there is a marked difference between the gap created when seated on the chair and

working on the table to process computer work. This problem could be solved if the

height from floor to top of backrest could be increased to 95.00cm, the height from floor

to seat pan could be changed to 45.00cm, or the seat pan width could be increased to

42.00cm while the depth could still be retained at the current dimension. The height

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from seat pan to top backrest could increase to 50.00cm. The backrest width may still be

maintained at 44.12cm. However, a more acceptable action is to provide an adjustable

chair; (2) The backrest was not covered with foam and leather, causing the customers

back to rest directly on the metallic frame; (3) The backrest was also not big enough to

support the customers back (see Table 1, with backrest width as 44.12 cm); (4) thebackrest did not serve the customer at all in the typing position: in the typing position,

customers had to stoop forward; (5) Since the legs of the chairs were too low (see Table

1, where the height from the floor to seat pan is 43.81 cm), the effects of the reaction of

the chair against the buttocks of the customer was felt more than in high chairs. It was

observed that for the high chair, the reaction was distributed and the effect of the

reaction felt by the customer was reduced. However, for the short chair, the reaction

was concentrated and had more effects than the high chair. (6) An additional

shortcoming of the cybercaf design was that the computer monitor was above the eye

level of customers at sitting position (Bergqvist and Knave, 1994). This was not good

enough, as the customer must tilt his or her head and neck up through an angle to view

the monitor. This position was inconvenient and tiring. Whenever the head was tilted,and remained in the same position for a long time, pain would be felt on the spinal cord

and this made customers get tired easily and even affected the health of customers. (7)

Another flaw of the design was that the chair was not provided with an arm rest (Table

1 shows no results on armrest since it was not encountered in the survey). The elbow of

the customer therefore dangled in the air while typing, and the biceps muscles were

greatly stressed trying to keep the hand hanging in space.

The literature value for angular movement of 45o, back support tilt of 30

oand elbow

support height of 23-33cm has not been confirmed or disproved by the survey. A

comparative analysis of results obtained with those reported in Goonetilleke and

Feizhou (2001) reported chair height of between 31-33cm adequate for the South Chinaregion Chinese population, which seemed lower than the range of values obtained from

this survey. The data collected for the current study showed that the height of the chair

from seat pan to top backrest is 49.06cm (range: 34.50-80.00cm, standard deviation:

19.02cm). The height of the chair from floor to top of backrest was observed to have a

mean of 88.56cm (range: 69.00-125.00cm, standard deviation: 29.23cm). The height

from floor to seat pan was 43.81 (range: 41.40-45.50cm, standard deviation of 2.14cm).

In the cybercaf industry, space was a great limitation. However, some cybercaf

operators optimized the use of their space thereby providing less comfort for the user

while others did not take advantage of space. Figure 2 showed an appreciable space

economy demonstrated by the cybercaf by positioning the system unit on a shelf while

only the monitor, keyboard (Smith and Cronin, 1993) and mouse were positioned on the

table. Unfortunately, space was not fully utilized this way in cybercafs XY, XYB and

XYC (Figures 1, 3 and 4) since the system units often competed with the customer for

space as the customers leg positions during browsing were restrained.

5.1 Ideal/Proposed sitting position at cybercafeFrom extensive literature scanning and field experience, a possible sitting posture which

reveals posture features such as distance of customers eye position from monitor,

sitting height, chair height and other ergonomic features indicate that a cyber caf could

be designed according to standards by regulatory authorities. In summary, the following

features were reflections of a standard sitting posture emerging from the study

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comparing the anthropometrics of the users to the dimensions and positions of the

monitor, chair/desk: (1) The top of the monitor should be placed at eye level for proper

head and neck position (Bergqvist and Knave, 1994); (2) Back rest should be covered

with foam and leather and the backrest positioned in such a way that it is always utilized

(Carter and Banister, 1994); (3) The chair should be high enough (about 1.44cm) and aconsiderable portion of hip and thigh (on the average of about 41.00cm) supported by it

in order to reduce the reaction on customers hips (Toomingas and Govhed, 2008); (4)

Chair height should be adjustable to allow for extreme height e.g. very short or very tall

(Toomingas and Govhed, 2008; Nag et al., 2008); (5) Arm rest should be available to

support the elbow during typing (Chen et al., 1994; Human and Rempel, 1995); (6)

Hand rest should be at the same level with the keyboard; (7) There should be no leg

restrictions under the table to restrict free movement of customers legs; (8) Footrest

should be such that it supports the leg and may best be positioned such that the knee is

bent at 900

at work, a position that requires minimum energy loss at work (Eruksrud and

Bohannon, 2003).

6 Conclusion, study limitations and future studiesThis paper has presented a framework for the ergonomic evaluation of cybercafs with

particular reference to those located within the territory of an academic environment in

a developing country. It was discovered that the cybercaf chairs of many of the

cybercafs visited was the major pitfall of the caf design. This was due to the fact that

chairs were too short, no hand rest was provided and there was no significant backrest.

Other shortcomings of the design included the fact that the chairs were stationary as

opposed to roller chairs. There were restrictions to the movement or positioning of

customers legs under the table; the workspace was too small and the top of computer

monitor was above eye level of an average height customer. This is a new contributionto knowledge in the area of cybercaf design in the developing country context. The

area is worthy of further empirical analysis. The information presented in the study

would improve customer satisfaction thereby guaranteeing patronage and should have

positive economic implications, which may affect companys profits. In order to attain

competitiveness, cybercafs should be designed in a customer-friendly manner. In this

work we have evaluated designs and suggested inputs as indicated in the section on

results that would make customers more comfortable while using the Internet in a

cybercafe. Although no cost analysis was made, the suggestion are however practicable.

This research has some limitations. An important drawback of the work is the lack of

sufficient reliability due to the limited number of respondents. For an academic and

theory-based work, it may require a sample of over 350 subjects to effectively examine

hypotheses. Future studies may improve on this. Another important issue in cybercaf

design is to permit an acceptable level of air circulation/flow and ventilation for

maximum efficiency at the cybercaf workstation. From field visits, it is observed that

ventilation in many cybercafs in Nigeria is very poor. However, the issue of ventilation

in cybercaf design was not covered in the study. Also, noise, in terms of location of

cybercafs away from noise sources such as generators, noisy markets, car

garages/parks, etc, which may reduce concentration at work, hence productivity, at

cybercaf workstation, has been omitted in this study. Further studies may cover this.

Tables 3 and 4 show a non-overlapping set of ranges. We thought that the range was a

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convenient means of measurement and hence used the range. This is an observed

weakness of the study. It is suggested that other statistical measures could be used to

avoid this prob

ESSA Vol 22 1 2010

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