Speaker : Professor Candice ChristiePresentation Title : Putting the worker at the centre of the ‘human-machine’ interface

IntroductionOur health affects our work

IntroductionAnd our work affects our health in many ways

Introduction

The uniqueness of the work environment in South Africa

IntroductionIndustrially Developing Countries have a vast array of:

• Cultures

• Availability of resources

• Levels of infrastructure

• Work environments/conditions

O’Neill (2000)

IntroductionSouth African context:

• South Africa is a middle income country• Extremes of wealth and poverty• Technologically advanced • Preponderance of manual work• Very diverse work situations

Introduction

• Differing levels of education• Differing socio-economic strata• Living conditions• Nutritional habits• Physical work at home/after hours• Disease patterns

IntroductionHow work affects our health

How work affects our health

Physical affects of work: FatigueLEVEL Oxygen

consumption(mlO2.kg-1.min-1)

Energy Expenditure (kcal.min-1)

Heart Rate(bt.min-1)

Light 6.1-15.2 2.0-4.9 >90Moderate 15.3-22.9 5.0-7.4 90-110Heavy 23.0-30.6 7.5-9.9 110-130Very Heavy 30.7-38.3 10.0-12.4 130-150Unduly Heavy 38.4- 12.5- <150

Saunders and McCormick, 1992

Physical affects of work: SA example

Christie, 2008

Variable 1st Quarter

2nd Quarter

3rd Quarter

4th Quarter

WHR(bt.min-1)

121(11.1)

119(12.5)

126(12.5)

127(13.3)

VO2

(ml.kg-1.min-1)19.9(6.5)

18.8(6.3)

21.8(6.8)

22.9(7.2)

EE(kJ.min-1)

26.4(8.6)

24.9(8.2)

28.8 (8.6)

30.3(9.4)

Physical aspects of work

16

18

20

22

24

26

28

30

32O

xyge

n C

onsu

mpt

ion

(ml.k

g-1.m

in-1)

Task A Task B

*

Physical aspects of work

Body mass loss: 1.94 kgChristie, 2008

Physical aspects of work

Energy Deficit: 8661.8 kJChristie, 2008

Physical aspects of work

Christie et al., 2008

TASK Heart Rate(bt.min-1)

Oxygen Uptake(ml.kg-

1.min-1)

Oxygen Uptake(L.min-1)

Cutting122(14)

21.42(8.97)

1.29(0.54)

Topping 117(14)

19.63(8.38)

1.19(0.50)

Stacking 125(17)

22.96(8.67)

1.38(0.51)

Overall121(15)

21.34(8.41)

1.29(0.50)

Physical aspects of work

Log

Mass

ActionCompressive Force

(N)

Shearing Force(N)

10 kg 1 hand 1213 286

2 hand 2924 333

60 kg 1 hand 3593 854

2 hand 10794 996

120 kg 1 hand 5398 1308

2 hand 18370 1526

Christie et al., 2008

Physical aspects of work

Todd, 2007

0

10

20

30

40

50

60

70

0 2 3 5 7 8 10

Time (s)

Posi

tion(

Deg

rees

) and

Vel

ocity

(m.s

-1)

Lateral velocitySagittal PositionTwisting velocity

Psychological aspects of workWork schedules

Psychological aspects of workCommuting to work

Psychological aspects of workBalancing work and family

Psychological aspects of workControl at work, demands and decision latitude

• High psychological demands

• High levels of decision making authority

• High levels of skill utilization

• ‘Decision latitude’

= self esteem and self efficacy

Psychological aspects of workControl at work, demands and decision latitude

• Jobs that make high demands

• Offer little ‘decision latitude’

= Job Strain= More likely to suffer psychological distress= Higher risk of CDL= Higher risk for unhealthy coping behaviours

Psychological aspects of workBalance between efforts and rewards

High Efforts

Low Rewards= poor health

HealthOur health affects our work

Quadruple burden of disease

The Lancet 2009 374, 934-947DOI: (10.1016/S0140-6736(09)61087-4)

Impact of health on work performance

High work demands

Poor health

= less productive

Incidence of Poverty

World Health OrganizationWorld Health Organization:

“Wealth of the poor people is in their individual capabilities and their ‘assets’, the most important being their health

which is their most precious commodity”

World Health Organization• Good health enables poor people to participate in the job market

• It is the key to productivity particularly in a people dominated working environment

• Physically healthy, strong body is an asset

• While a sick and weak body is a liability both to employee and employer

Coupled with nutritional statusPROTEI

N(g)

FAT(g)

CHO(g)

TOTAL ENERG

Y(kJ)

RDA 65.0 30.0-80.0

100.0 8000.0

Group 1

40.5 26.7 110.9 3949.1

Group 2

56.2 23.1 186.8 5346.0

Christie, 2008

Basic Human Needs

Self-Actualisation

Esteem

Love

Safety

Biological and Physiological Needs

Adapted from Abraham Maslow (1943)

South Africa’s unique environment

HIV/AIDS;Infectious diseases

5.3 mill South Africans with HIV/AIDS (UNAID, 2003)

Non-communicable Diseases

Bradshaw et al, NCDs: a race against time

Non-communicable Diseases

Bradshaw et al, NCDs: a race against time

Non-communicable Diseases

Bradshaw et al, NCDs: a race against time

DALYs in IDCs in 2004

(Econex, NHI Note 2, 2009)

DALYs for developed countries 2004

(Econex, NHI Note 2, 2009)

Absolute burden of disease

(Econex, NHI Note 2, 2009)

(Econex, NHI Note 2, 2009)

Solutions

1. Worksite Wellness Programmes

2. ‘Fitting the Job for Total Worker Health’

Solutions

Worksite Wellness

Programmes:

‘Change behaviours’

Work itself:

‘Causes behaviours’

Work impacts:

1. Eating and exercise patterns

2. Lack of decision-making are strongly associated with:

• obesity, • alcohol consumption, • smoking and,• lack of exercise

Ergonomics Solution – an exampleImproved work organization:

Time, space, material and, social support for:

Improvements in: Dietary choices, smoking cessation, participation in exercise, and improved work-family balance

Where does Ergonomics fit in?• Occupational ergonomics is the science of ‘fitting the task to the worker’

• It is not only concerned with work station design or preventing MSDs

• It provides a framework to address the workplace preconditions of the job stress

Ergonomics and WWPErgonomists:

Address the broad range of work organization issues such as job design to:

• Increase decision latitude • Optimize work schedules • Improve quality of supervision

Engaging an ergonomist can remove obstacles to programme participation and increase trust in employers

Participatory Approach

Participatory ergonomics offers a useful model for programme design starting with engaging workers themselves in identifying their health priorities and

environmental factors that affect their health

Ways to incorporate Ergonomics1. Partner with your organizational team

2. In programme goals and activities accommodate for the physical and social demands of workers

3. Use a participatory approach

Thank you!

Prof. Candice ChristieDepartment of Human Kinetics and ErgonomicsRhodes UniversityGrahamstownc.christie@ru.ac.za@CandiceHKE