Transcript Physical profile of the workforce_THofmann

Physical profile of the workforce and the effect on
work capacity
MMPA Congress
2012
Tia-Mari Hofmann
RFA JV
Physical and Functional Fitness Prerequisites…
‘--- survey of a cross-section of OHC officers working in Queensland and New
South Wales mines indicated that a lack of fitness, stamina and skill rank highest ---as contributors to injury’
‘--- broader view of this concept (‘fit for work’) should consider the interaction
between a worker’s capacities and the demands of the job, and how much they do,
or do not, match. It should also take a long-term view of ----- health and fitness --over a career --- and cumulative effects of work demands’
‘---- the expectation that all members of the general workforce could perform all
mining work-tasks, and that they can do so with no risk or injury, may be
increasingly unrealistic.’
‘--- physical activity and fitness levels have arguably declined, and levels of
overweight and obesity clearly increased ---’
(abstracts from a paper by Parker and Worringham)
… to sustained health, safety and career opportunities
What does the South African workforce look like?
Contents
• RFA Data
• Demographics of RFA Centres
• RFA utilisation
• Physical profile of the workforce:
- Work capacity
- BMI
- Age
- Gender
- Other factors impacting on work capacity
• Nature of the work
• Functional analyses of occupations
• Functional work capacity as part of medical surveillance
RFA Data
• Rehabilitation and Functional Assessment (RFA) Test Battery
developed over the past 11 years
• Minimum standards for fitness to perform manual work in a safe
manner
• Test standards originally derived from:
- Internationally accepted scientific principles
- Field studies
- Testing healthy, in-service employees (SA mining industry)
• RFA Database comprises of 324 235 work assessments
• 10 mining companies using the test battery
RFA Centres
RFA Assessment
Objective assessment of work capacity
Physical Work Capacity Test
Functional Work Capacity Test
Aim:
To determine the inherent aerobic
capacity to perform manual work
Aim:
To assess functional abilities
necessary to perform a specific task
Consists of:
A 10 minute step test
Consists of:
21 simulated work activities and
environmental obstacles
© Rehabilitation and Functional Assessment Joint Venture All rights reserved
© Rehabilitation and Functional Assessment Joint Venture All rights reserved
Discussion
Work Capacity
• UK National Fitness survey: 10% of males in the age group of 35-55
years have a degree of low work capacity although they are
nutritionally reasonably fed and of average health (Durnin, 1992)
• People are not equal: When the distribution of genetically endowed
cardiac output or haemoglobin levels were examined some
individuals were clearly at a disadvantage when compared to others
(Durnin 1992, Bouchard and Shephard 1994)
Cardio respiratory features of volunteer subjects
Parameter2
Group - SA mining
industry (n = 16)
Trained males
(not world class)
Inactive males
n = >200
Age: years
36.0 ± 9.4
25.8 ±10.7
43.3 ±13,0
Height: cm
171 ± 6.8
179.6 ± 6.2
174,9 ± 6.3
Mass: kg
68.3 ± 7.0
75.1 ± 8.8
76.8 ± 9.8
MAC: ml/min
2 404 ± 43
3 663 ± 571
2 718 ± 568
MAC: ml/kg/min
34.5 ± 6.5
48.9 ± 6.8
35.8 ± 8.3
Oxygen pulse1
12.4 ± 4.3
20.6 ± 3.1
16.6 ± 2.5
Source: Hollmann et al
1Index
of cardiorespiratory efficiency: VO2 Max (maximal aerobic capacity, MAC in ml/min)
expressed in terms of the concurrent heart rate maximum i.e. ml/beat
2All
data expressed as means ± SD
Findings
• MAC (Maximal aerobic power or VO2 Max) expressed in terms of
body mass (ml/kg/min) suggest that the local mining population
can be linked to an sedentary (inactive) group of males generally
10 years older.
• Oxygen pulse, a measure of cardio respiratory efficiency is also
significantly lower than the untrained/inactive reference group.
Physical profiles of the overall workforce
Body Mass Index (BMI)
Females (n = 24 734)
Males (n = 251 917)
52%
33%
26%
29%
16%
18%
10%
10%
4%
< 20
20 - 25
25.01 - 30
30.01 - 35
2%
> 35
© Rehabilitation and Functional Assessment Joint Venture All rights reserved
BMI and the effect on work capacity
BMI (> 30) indicative of obesity
Ozcelik et al (2004) were able to demonstrate a significant negative
correlation between maximal work rate (expressed per kg body mass)
and BMI.
Mainly due to
- excess in body fat
- increase in type 2 muscle fibres and an decrease in
type 1 muscle fibres (Kissebah and Krakower 1994)
- progressive decrease in heart reserve
- reduced cardiac performance during progressive work
rate exercise (Salvadori et al.1999)
BMI and the Effect on Work Capacity
BMI (< 20) indicative of individuals being underweight
(SIMRAC GAP 505)
• Less lean body mass and muscle mass influence work output
(studies done in Guatemala described by Torun et al. 1989).
• In relation to work capacity the most important organ is skeletal
muscle, although the heart and oxygen carrying capacity of the
blood plays a significant part. It is more than just the muscle mass,
but the muscle fibre and the strength of the muscle contraction
(Durin 2004).
• If the work task involved no external load e.g. walking, household
chores (cooking, sweeping), a minimum BMI of 17 is acceptable.
BMI and the effect on work capacity
BMI (< 20) indicative of individuals being underweight
(SIMRAC GAP 505)
• A different set of criteria is required when work tasks are heavier in
nature in e.g. cutting sugar cane, pushing a wheel barrow,
shovelling etc. When work tasks entail handling an external load /
the need to use the body mass to exert part of the force.
• A low body mass makes work of this nature much more physically
demanding.
Age distribution
of the overall
workforce
overall workforce
of the
Age distribution
Males (n = 254 821)
Females (n = 25 271)
93%
60%
27%
3%
4%
2%
< 20
20 - 40
41 - 50
10%
0%
51 - 60
0%
0%
> 60
© Rehabilitation and Functional Assessment Joint Venture All rights reserved
Effect of age on work capacity
• Age influences the efficiency and efficacy of muscle contraction
• Proportion of muscle fibre types alters
• Muscle mass diminishes and strength of the contraction is
reduced (Durin, 1992, Sallis 1993, Yang et al. 1999)
• Previous RFA studies showed a statistically insignificant effect of
age on work capacity, with previous mining experience which
may act as a counter to deteriorating of fitness levels generally
found in a sedentary, aging population.
Pathology
Most prevalent diagnoses amongst the overall workforce
Clients with pathology (n = 13 339)
24%
20%
12%
11%
6%
Fractures/injuries/wounds
TB
HIV
Respiratory diseases
Low back pain
5%
General symptoms and
signs
4%
4%
4%
Cardiovascular
Contusions
Hypertension
3%
Malaise and fatigue
© Rehabilitation and Functional Assessment Joint Venture All rights reserved
(Group representation expressed as a percentage of the total number of clients with pathology, not of the gross overall number of clients)
Gender
Factors impacting on work capacity
Females are physiologically disadvantaged
• Lower haemoglobin concentration and arterial O2 content (Mitchell
et al. 1992)
• 15 to 30% less aerobic capacity than their male counterparts
(Wasserman, 1999)
• Physical strength: women are weaker than men, usually attaining
between 60 and 90% of the men’s muscle strength and work output
(Kroemer et al. 2001)
Other factors such as…
Anthropometrics
Height has an impact on work capacity
(Farazdaghi and Wohlfart 2001)
…impact on work capacity
Height and work capacity
Anthropometric Data
NIOSH Mining: Underground Workstation Design Principles
5%
NIOSH Males
RFA Data Males
NIOSH Females
RFA Data Females
1.64 m
1.65 m
1.51 m
1.49 m
50%
95%
1.75 m
1.72 m
1.62 m
1.62 m
1.86 m
1.86 m
1.73 m
1.73 m
Women in Mining
Ergonomic Design Principles
NIOSH Males
RFA Data Females
5%
50%
1.64 m
1.49 m
1.75 m
1.62 m
95%
1.86 m
1.73 m
Anthropometrics
Impact on Functional Work Capacity
The nature of the work determines…
The impact of low or high BMIs, age, anthropometrics and
low work capacity are determined by the physical nature of
the work.
…the degree of risk
Questionnaires
Work visit
Observation
ABOVE shoulder
Load
handling
Functional analyses
Interview
Work visit
Measurements
Weight: 60kg
Physical demands
Medical Surveillance
Medical surveillance
Physical Assessment
Heat Tolerance screening
Functional Work Capacity Assessment
Ensuring a healthy, safe productive worker
through all phases of employment
Employment
Pre-employment
Preventative
Baseline assessment
Effective placement
Preventative & reactive
Periodical examinations
Establish and monitor work capacity
profiles
Rehabilitation
Disability management
Lifestyle & wellness programs
Exit / retirement
Functional, healthy individual
© AngloGold Ashanti Health All rights reserved
Aerobic fitness: A health and safety requirement
Removal of an aerobic fitness standard for fire fighter recruits was
associated with higher levels of adverse health and occupational
related outcomes during subsequent training.
(Wynn P. and Hawdon P.: Cardiorespiratory fitness selection standard and occupational outcomes in
trainee fire-fighters, Occupational Medicine Advance Access, 2011)
‘In order that people may be happy in their work,
these three things are needed:
They must be fit for it.
They must not do too much of it.
And they must have a sense of success in it.’
- John Ruskin -