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IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
International Journal of Engineering & Scientific Research
http://www.ijmra.us
136
October
2014
Integrating Ergonomics tools in Physical
Therapy for Musculoskeletal Risk Assessment
and Rehabilitation- A Review
Sanjib Kumar Das*
Suman Mukhopadhyay *
Abstract
Background: Ergonomics or human factors engineering is a multidisciplinary science that
synergizes man, machine and the working environment to optimize productivity and
performance as well as to enhance and augment the safety, health and well-being of the worker.
Ergonomics is concerned with the ‗fit‘ between people and their technological tools and
environments. It takes account of the user's capabilities and limitations in seeking to ensure that
tasks, equipment, information and the environment suit each other.
Physiotherapy / Physical therapy, is a health care profession primarily concerned with the
remediation of impairments and disabilities and the promotion of mobility, functional ability,
quality of life and movement potential through examination, evaluation, diagnosis and physical
intervention. It is believed that knowledge of ergonomics help the physical therapists play a
greater role in numerous assessments and in different aspects of physical therapy care and
rehabilitation.
Furthermore, rehabilitation ergonomics play a proactive role in the prevention of
musculoskeletal injuries by utilizing ergonomic principles of worksite redesign, tool
selection/modification, work method design, ergonomic education, fitness and early intervention.
Rehabilitation ergonomists specialize in functional evaluation, improvement of functional work
performance, education of the worker and redesign of work to reduce musculoskeletal stressors
but they must analyze both the human who perform work activities and the setting in which they
work. Rehabilitation Ergonomics is still in its early stages, while it gives immense innovative
scope for physiotherapists/physical therapist to act as one.
Brief description of subject:Ergonomic tools are increasingly being found to be extremely
useful for assessment / diagnosis as well as in treatment and prevention of work related
musculoskeletal disorders, workplace risks and rehabilitation ergonomics.
* Ergonomics and Human Factors Engineering, National Institute of Industrial Engineering
(NITIE), Mumbai, India 400 087
IJESR Volume 2, Issue 10 ISSN: 2347-6532
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A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
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International Journal of Engineering & Scientific Research
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2014
Physical exposure to risks for potential work- related musculoskeletal injuries is possible by
using a variety of methods with subjective and objective approaches like questionnaires on
health and wellbeing, physical, psychosocial and psychophysical risk factor perceptions,
computer based evaluation tools, tools for work system and product design by simulation and
biomechanical models, instruments for evaluating work environment, checklists for workplace
evaluation, rehabilitation ergonomic components etc. The paper primarily addresses to integrate
ergonomics and physiotherapy in assessment and rehabilitation.
Clinical implication:A strategy that considers both the ergonomics expert‘s view and the
practitioner‘s needs for developing a practical exposure assessment tool is discussed that
suggests ways in which physiotherapy treatment and rehabilitation can be geared to recovery of
working capacity. Integrating ergonomics into rehabilitation efforts of all kinds holds significant
promise for improving outcomes.
Keywords: Ergonomics, Human Factors Engineering, Rehabilitation, Physiotherapy,
Musculoskeletal Disorder
1. Introduction of Ergonomics
The foundation of the science of ergonomics appears to have been laid within the context
of the culture of Ancient Greece, as early as in the 5th century BC, who were believed to have
used ergonomic principles in the design of their tools, jobs, and workplaces (Mukhopadhyay et.
al.2012).
Ergonomics (or human factors engineering) is a multidisciplinary science concerned with
the understanding of interactions among humans and other elements of a system and the
profession that applies theory, principles, data and methods to design in order to optimize human
well-being and overall system performance. Ergonomics draws on many disciplines in its study
of humans and their environments, including anthropometry, biomechanics, mechanical
engineering, industrial engineering, industrial design, information design, kinesiology, anatomy,
physiology, pathology and psychology. The term ergonomics derives from Greek Έργον,
meaning "work" and Νόμος, meaning "natural laws", coined by Wojciech Jastrzębowski in
1857(Mukhopadhyay et. al.2012).
The ergonomic tools aim to evaluate risk and consequences. Most of the tools attempt to
quantify the physical load or psychosocial conditions. Several tools are oriented to quantifying
outcomes such as pain or disability. A few tools consist of economic models that try to evaluate a
potential change in terms of productivity, costs and financial benefits. There is no ‗best‘ tool.
The choice of tool depends therefore on what needs to be done. Thus, it can be said that, just
because having a hammer in the hand doesn‘t mean the problem is a nail (Neumann, 2006).
Every tool has a blind spot i.e. there are often intangible effects from the changed
projects. Hence, it is helpful to try and capture these with more qualitative approaches especially
by interviewing the people involved. This can provide insight into the effects and process of
change that might not be clear from a particular tool. A good tool makes a big difference, but
how the tool is used is also critical. It‘s the skill of the carpenter not just the sharpness of the saw
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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2014
that counts. With the time, new tools are being continuously developed and old tools are
becoming obsolete and unavailable (Neumann, 2006).
1.1 Rehabilitation Ergonomics
Rehabilitation Ergonomics is the practice of applying scientific and functional principles
to provide a match of work and worker that prevents injury or assists in the return to work
process. They must analyze both the humans who perform work activities and the setting in
which they work. Rehabilitation ergonomists specialize in functional evaluation, improvement of
functional work performance, education of the worker and redesign of work to reduce
musculoskeletal stressors (Marras, and Karwowski, 2006).
Rehabilitation ergonomists specialize in the prevention of musculoskeletal injuries by
utilizing ergonomic principles of worksite redesign, tool selection/modification, work method
design, ergonomic education, fitness and early intervention. They perform as part of a larger
prevention team often including engineer ergonomists, safety departments, production managers
and other medical professional involved in prevention. Ergonomic training and education are a
foundation for the prevention practice of the rehabilitation ergonomist (Marras and Karwowski,
2006).
1.2 Ergonomics and Physiotherapy
Physiotherapy / Physical therapy is a healthcare profession that works with people to identify and
maximize their ability to move and function. This means that physiotherapy plays a key role in
enabling people to improve their health, wellbeing and quality of life. Physiotherapist practice
however, occurs across a wide spectrum of health care and as a profession requires solving
complex and poorly defined practice problems (Edwards‘s et. al. 2004). Thus it is believed that
with ergonomic understanding it will play a greater role in numerous assessments and in
different aspects of physical therapy care.
2. Inventory of Tools for Ergonomic Evaluation- Brief Review
The Ergonomics Tools reviewed here is intended to assist practitioners in identifying potentially
useful methods for evaluating working environment in their professional work (or perhaps
evaluating their own working environment). The emphasis here is on tools that can be used to
evaluate a workplace or a potential design for a workplace, often in some kind of quantitative
way.
2.1 Questionnaires on Health & Wellbeing
The tools in this category all focus in the effect work has on the individual. This might include
health outcomes, pain surveys, stress. The distinction between these and the psychosocial tools is
the change from the experience of the workplace to the effects that workplace has on the
individual.
2.1A. Pain, Disability & Symptom surveys
IJESR Volume 2, Issue 10 ISSN: 2347-6532
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i. NIOSH survey – a musculoskeletal survey by the US NIOSH (Stanton et al., 2004).
ii.‗Nordic‘ symptom questionnaire – A ‗standardized‘ questionnaire that allows description of
pain and disability for various body parts (Kuorinka et al., 1987). The tool has since been
broadly adapted and applied in research.
iii. SF-36, SF-12 – questionnaires (36 items & a less detailed 12 item version) on general health
including physical and mental health (Ware et al. 2000).
iv. Tools for Modified Work - A process and checklist set supporting efforts of returning injured
workers to the workplace with a focus on communications between the workplace and the care-
giver.
From the Quebec department of Public Health.
2.1B. Fatigue, Motivation, Satisfaction
i. ORS – Organizational Role Stress Scale (Pareek, 1983)
ii. Job Satisfaction tool (Spector, 1997). One example found is a three question item in (Pousette
and Hanse, 2002)
2.2Questionnaires on Risk Factor Perceptions
These tools are intended to be used to survey groups of workers on their perception of physical
and psychosocial work environment. It is common for these tools to have several questions on a
particular factor that are then combined to generate a single index for that factor.
2.2A. Physical Risk Factors
i. DMQ – The ‗Dutch Musculoskeletal Questionnaire‘ from TNO (Hildebrandt et al., 2001;
Stanton et al., 2004).
ii. Nordic Safety Questionnaire – A questionnaire tool from Scandinavian researchers with a
Safety-culture focus (Kines et al., 2011).
iii. RFQ - Risk Factor Questionnaire a 25 item questionnaire with a focus on risk factors for low
back pain (Halpern et al., 2001).
2.2B. Psychosocial and Psychophysical
i. Job Content Instrument – perhaps the best-known psychosocial questionnaire. Based on the
‗Demand-Control‘ model by Karasek and later extended to include a ‗Support‘ dimension
(Karasek et al., 1998).
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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ii. QPS Nordic & QPS34+ – A 123 question (34 question short form) instrument on stressors in
the working environment.
2.3 Computer Based Evaluation Tools
This list focuses on tools explicitly oriented to computer use. However many of the ‗Checklist‘
observational tools have also be implemented onto a computer or handheld PDA type device.
Computer implementation can speed use and improve usability.
ii. ErgoIntelligence and Ergomaster – Software tools implementing a number of different
checklist tools.
iv. ERGOMIX – a method for integrating images of real operators with CAD drawings to
evaluate workstation layout (de Looze et al., 2003).
v. ERGOWATCH – A computerized ergonomics ‗toolbox‘ including the Watbak biomechanical
model, NIOSH equation, Snook Tables, and a job demands / worker capabilities analysis tool.
From the University of Waterloo (www.uwaterloo.ca).
vi. FIT – Flexible Interface Technology is a Personal Digital Assistant (PDA) based tool for the
observation of work tasks (Held et. al.1999).
vii. HARBO – A simple computer aided observation method for recording work postures
(Wiktorin et al., 1995).
ix. MVTA – Multimedia Video Task Analysis tool for analyzing video sequences in terms of
postures and task performance. Developed at the University of Wisconson-Maddison.
x. NIOSH lifting equation – A well known tool for calculating maximal permissible lifting loads
(Waters et al. 1993) and (Waters and Putz-Anderson, 1999). This tool is often implemented in
other software packages like Ergowatch.
xi. The Observer XT – An advanced video analysis tool suitable for task analysis and usability
evaluation, allows PDA based assessment or integration of biophysical signals like force, EMG
etc.
xii. PEO – Portable Ergonomics Observation method for computer supported field observation,
developed in Sweden (Fransson-Hall et al. 1995).
xiii. Posture Program – A relatively simple video based approach, allowing quantification of
trunk and arm postures and velocities during work (Neumann et al., 2001).
xiv. VIDAR/PSIDAR – A video based system allowing employees to rate both physical
(VIDAR) and psychosocial (PSIDAR) working environment at chosen points in time from the
video (Kadefors and Forsman, 2000).
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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2.4 Tools for Work System and Product Design
Tools in this category are useful in the evaluation of workplaces in the design stage. These tools
can also often be used to evaluate existing designs.
2.4A. Complex Human Simulation Models
―Complex‖ computer models include higher-end products designed to allow 3D modelling of
humans in a 3D environment such as CAD. A complete discussion of the capabilities and utility
of these tools for practitioners and researchers has been executed by Sundin (Sundin et al.
2004).These tools often contain various ergonomics assessment approaches such as reach and fit
checking, NIOSH equation, modified checklist approaches and biomechanical models to
determine physical loading and exposure to risk factors.
e.g.: Jack, Ramsis, SAFEWORK, ENVISION/ERGO, eMHuman, ERGOMan, ManneQuinPRO.
2.4B. Simpler Computerised Human Biomechanical Models
These models may be two or three dimensional and may even consider repeated or cumulative
loading as part of the assessment. These are good tools both in design stages and also to quantify
loading of existing systems to help identify areas for improvement and quantify the extent of
load reduction in a particular situation (Neumann, 2006).
i. 3D SSPP - The University of Michigan‘s famous 3D Static Strength Prediction Program allows
fast determination of 3D loads for specific work actions.
ii. 4D WATBAK – A simple model from the University of Waterloo that allows modeling of
single work activities as well as calculating cumulative load over a full shift. It have been risk
calibrated in epidemiological research (Neumann et al., 1999).
iii. BakPak - University of Windsor model - predicts spinal loads based on reach location inputs.
2.4C. Design Checklists and other Design Tools
This includes ‗paper‘ checklists or working concepts which may even be implemented in a
computer system that can support the evaluation and application of ergonomics factors in process
design. These tools tend to operate at different stages of the design process but share a common
strength in that they have potential to connect to existing engineering tools and processes.
i. ERGONOVA – Ergonomics addition to the classic ‗value stream mapping‘ tool for production
system improvement (Jarebrant et al., 2004).
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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2014
ii. ErgoSAM - An ergonomic add-on for the Swedish SAM method for standard time allocations
(which is a common job planning tool, an MTM system). Provides red-yellow-green
determination based on the engineer‘s determination of task requirements (Laring et al., 2005).
iii. FMEA tools – Failure Mode Effect Analysis; a common risk analysis tool that has been
adapted to include ergonomics aspects in product and production process development (Munck-
Ulfsfalt, 2004).
2.4D. Flow Simulation Tools
A number of different flow simulation tools exist which can be used to assess human factors in
terms of time utilized for different activities in the system and can also be used to test how the
system performs under different work organization strategies. Flow simulation can also be used
in combination with human-biomechanical simulation or other tools to predict loading with
different configurations (Neumann, 2006).
e.g.: Simul8, Delmia, Technomatix, microSAINT.
2.4E. Tools for Product Design
A couple of literatures do exist in this area mentioning about few tools oriented to the
determination of ergonomics issues in the design of the product.
i. Quality Function Deployment – an adaptation of a well known design tool to integrate human
factors considerations into early design stages and provides an example of deboning knife design
(Marsot, 2005). The method, based on the ‗house of quality‘ approach supports balanced
consideration of varying requirements based on their priority and the extent the criteria is
fulfilled by a given design option.
ii. Kansei Engineering – More an approach than a tool this method focuses on designing products
according to the user‘s feelings and impressions (Nagamachi, 2002).
2.5 Instruments for Evaluating Work Environment
These tools actually are oriented towards the evaluation of individuals while at work. This
includes simple tools and sophisticated measuring equipment.
i. Tape measure – a classic but useful tool for reach and fit measures.
ii. Stopwatch – time remains an important aspect of biomechanical exposures
iii. Force gauge – another classic tool; fish-hook type scales are cheapest but a push pull gauge
can be more versatile for measuring forces other than lifting.
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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October
2014
iv. Counter – A handheld counting tool that is helpful when counting repetition rates or parts for
estimating total loading.
v. Data Loggers – Advanced data collection system for measuring EMG or posture while
working (Hansson et al., 2003).
vi. Lumbar Motion Monitor – A device for tracking back postures in 3dimensions at work,
development headed by Marras at Ohio State (Stanton et al., 2004).
vii. SEIP – (Synchronised Exposure and Image Presentation); a tool allowing the presentation of
video recordings and synchronised load/force/EMG measurements on a computer screen
(Forsman et al., 1999).
viii. Vibration and Sound meters.
2.6 Checklists for Workplace Evaluation
Many checklist type tools exist both as paper forms and sometimes implemented into computer
programs. This list highlights a number of examples that are either well-known or provide
potentially useful opportunities for practitioners. It is quite common for ergonomic practitioners
to adopt a checklist for their own needs.
i. PLIBEL - Checklist, mostly of physical risk factors, (Kemmlert, 1995).
ii.RULA – Rapid Upper Limb Assessment tool provides a ‗score‘ for upper limb demands by
McAtamney and Corlett, 1993.
iii.REBA – Rapid Entire Body Assessment tool, similar to RULA but with a whole body focus
(Hignett and McAtamney, 2000).
iv.The Strain Index – Combines time, repetition, load, and posture into a single index focused on
hand/wrist load (Steven Moore and Garg,1995).
v. QEC – The ‗Quick Exposure Checklist‘ for assessing risk factors for work-related
musculoskeletal disorders (Li and Buckle, 1998).
vi. OCRA – A ‗concise‘, checklist based, index for assessing risk due to repetitive movements
(Occhipinti, 1998).
vii. OWAS – The Ovako Working Posture Analysis System for rapid assessment of postural
loads at work (Wilson and Corlett, 2010).
viii. WEST – (Work Environment Survey Tool) provides both traditional ergonomic and
occupational hygiene analysis possibilities (Neumann, 2006).
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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2014
ix. Ergonomithermometer – A Swedish language tool using a ‗thermometer‘ metaphor to help
assess risk levels.
x. Keyserling checklist – A classic, simple, risk factor checklist easily adapted tousers needs
(Keyserling et al. 1991).
xi. MAC – The Manual Handling assessment Chart, like the NIOSH equation this allows easy
assessment of MMH tasks.
xii. ManTRA – A checklist from the University of Queensland.
xiii. NIOSH equation – An approach to calculating a ‗maximum‘ permissible load for different
lifting circumstances (Waters et al. 1993) and (Waters and Putz-Anderson, 1999).
xiv. Psychophysical ratings – A rating made by someone of their own experience (‗psycho‘) of
loading (‗physical‘). A versatile approach pioneered by Borg and broadly applied in various
contexts (Borg, 1998).
3. Physical Methods of Assessment for work related Musculoskeletal risks
The physical methods are crucially used by ergonomist to obtain essential surveillance data
for the management of injury risks in the workforce. It is generally accepted that many
musculoskeletal injuries begin with the worker experiencing discomfort. If ignored, the risk
factors responsible for the discomfort eventually will lead to an increase in the severity of
symptoms and will be experienced as aches and pains. If left unchecked, the aches and pains that
signal some cumulative trauma eventually may result in an actual musculoskeletal injury such as
tendonitis, tenosynovitis or serious nerve compression injury like carpal tunnel syndrome.
Discomfort will also adversely affect work performance either by decreasing the quantity and
quality of work through increased error rates or both.
Various methods are now available for assessing exposure to the risks associated with work-
related musculoskeletal disorders, or identifying potentially hazardous jobs or risk factors within
a job. The aim of this paper is to give an overview of existing techniques, which can be used by
physiotherapist for clinical assessment of physical work load and associated exposure to work-
related musculoskeletal risks.
3.1 NMQ (Nordic Musculoskeletal Questionnaire) is used to find the prevalence of work
related musculoskeletal disorders in different anatomical regions such as neck, shoulders,
upper back, lower back, knees, elbow, wrists/hands, buttocks, ankles. Respondents are
asked if they have had any musculoskeletal trouble in the last 12 months and last 7 days
which have prevented normal activity. Additional questions elicit any accidents affecting
each area, functional impact at home and work (change of job or duties), duration of the
problem, assessment by health professional and musculoskeletal problems in the last 7
days (Kuorinka et. al. 1987). The NMQ is used as a questionnaire or as a structured
interview (Crawford, 2007). NMQ can be widely used by therapists as a screening tool
for work related musculoskeletal disorders.
IJESR Volume 2, Issue 10 ISSN: 2347-6532
__________________________________________________________
A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories
Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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2014
3.2 PLIBEL (method for the identification of musculoskeletal stress factors that may have
injurious effects) is a screening tool designed to identify ergonomic hazards in the
workplace, via the use of a checklist (Kemmlert and Kilbom, 1987). The checklist
consists of questions regarding work posture, movements, workplace or tool design.
These are answered in accordance with the body regions concerned, including neck
/shoulders and upper part of back, elbows /forearms and hands, feet /knees and hips, and
low back. The tool is useful for identifying risk factors for musculoskeletal injuries of a
specific body region, and has been applied in several studies (Vink, 1991and Jakobsson,
2003). PLIBEL results can serve as the basis for discussion on improvements to job
design and prevention of work related musculoskeletal disorders by the therapists.
3.3 QEC system (Quick Exposure Check for work-related musculoskeletal risks) has been
developed by Li and Buckle, 1998. The method includes the assessment of the back,
shoulder /upper arm, wrist /hand and neck, with respect to their postures and repetitive
movement. Information about task duration, maximum weight handled, hand force
exertion, vibration, visual demand of the task and subjective responses to the work is also
obtained from the worker. The magnitude of each assessment item is classified into
exposure levels and the combined exposures between different risk factors for each body
part are implemented by using a score table, in which higher scores are given to the
combination of two higher-level exposure of risk factors than the combination of two
lower-level exposures. Up to five pairs of combination /interaction are considered for
obtaining overall exposure scores of the back, shoulder /upper arm, hand /wrist and neck,
i.e. posture versus force, movement versus force, duration versus force, posture versus
duration, and movement versus duration. Field tests have also been conducted using the
system to assess 60 tasks in different occupations (Li and Buckle, 1998, 1999).QEC has a
high level of usability and sensivity. This method can be used by the therapist as it has
the advantage for quick assessment of the exposure to risks for work related
musculoskeletal disorders.
3.4 RULA (Rapid Upper Limb Assessment) is designed for assessing the severity of postural
loading and is particularly applicable to sedentary jobs (McAtamney and Corlett, 1993).
The method adopts the concept of OWAS, using numbers to represent postures with an
associated coding system (Karhu et. al. 1977). The range of movement for each upper
body part (head, trunk, upper and lower arm, wrist) is divided into sections that are
numbered. Number 1 is given to the range of movement or working posture where risk
factors causing load on the structures of the body segment are minimal, and higher
numbers are given to parts of the movement range with more extreme postures. If an
abduction or rotation is involved, the scoring is described beside the diagram. In addition
to posture recordings, RULA also considers the load on the musculoskeletal system
caused by static or repetitive muscle work and force exertion. This method can even help
the therapist to accurately estimate the level of intervention required reducing the risks of
injury due to physical loading on the operator and thus preventing work related
musculoskeletal disorders.
IJESR Volume 2, Issue 10 ISSN: 2347-6532
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Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A.
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2014
3.5 REBA (Rapid Entire Body Assessment) is developed on the basis of the RULA system,
but it is appropriate for evaluating tasks where postures are dynamic, static or where
gross changes in position take place. To use the tool, the observers select the posture or
activity to be assessed and score the body alignment using the REBA diagrams. This is
then combined with a load score to form the ‗coupling scores‘, which are further
processed into a single combined risk score using the table provided (Hignett and
McAtamney, 2000). The therapist can use this method for rapid assessment of standing
work and can suggest necessary ergonomic interventions.
3.6 OWAS (Ovako Working Posture Analyzing System), as developed by the Ovako Oy
Steel Co. in Finland and described in details in several papers (Wilson & Corlett, 2010).
The system defines the movements of body segments around the lower back, shoulder
and lower extremity (including the hip, knee and ankle) as four types: bending, rotation,
elevation and position. To use this system, the analyst makes an instantaneous
observation of the posture and records a four-digit code, representing the positions of the
back (four choices), the arms (three choices), the legs (seven choices) and force. The
recording procedure requires only a few seconds and can be used in conjunction with
random schedule of observations to obtain a summary description of posture. OWAS also
has action categories to reflect the magnitude of risks. The OWAS method (or its
modified form) has been used in several ergonomic or epidemiologic studies,
such as surveillance for ergonomic hazards at work (Karhu et.al.1981),
identification of strenuous tasks and activities in particular jobs, (Kant et.
al.1990, Scott and Lambe, 1996) characterization of exposure in epidemiologic
studies and evaluation of the effectiveness of ergonomic controls (Kivi and
Mattila, 1991).This method if used by therapist will provide earlier risk detention
capabilities and consequent prevention of work related musculoskeletal disorders.
3.7 (LMM)The lumbar motion monitor is a triaxial electrogoniometer that was developed to
record three dimensional components of trunk position, velocity and acceleration (Marras
et. al.1992). The system is designed to be worn on the back of the worker and to track the
worker‘s trunk motion during work. Marras (1992) reported that the LMM is about twice
as accurate as a video-based motion evaluation system. The electro-goniometer system
adopts a simple concept, i.e. direct measurement of joint angles. It is easy to use and the
recording has been found to be sufficiently accurate and reliable for epidemiologic
studies (Smutz et. al. 1994). If a patient or client experiences decreased range of motion
of spine due to any mechanical deficit, the therapist can use LMM to assess the range of
motion before manual therapy, and then make sure it is working by using the LMM in
subsequent interventions.
3.8 RPE (Borg Rating of perceived exertion scale) the measurement of work effort and
fatigue was one of the earliest challenges that ergonomists faced. The performance of
work in more deviated postures invariably requires more muscular effort, which in turn
may accelerate muscular fatigue but none of the other physical methods used to assess
discomfort or posture, yields information on the degree of work effort or on the level of
accumulated fatigue that could amplify an injury risks. The scale grew linearly with
workload and thus remained equidistant with regard to aerobic demands. By using 6 as
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the lowest number and 20 as the highest on the scale, a simple relation with heart rate for
healthy middle aged people was obtained. The Borg Ratings of Perceived Exertion Scale
provides a physiologically validated method for quantifying how much effort is involved
in performing physical work (Borg, 1998). The therapist can monitor the intensity of
exercise/ aerobics in healthy pregnant women by the mother‘s rating of perceived
exertion, because it is not recommended using target heart rate to determine intensity of
exercise during pregnancy, as there is increase in resting heart rate and decrease in
maximal heart rate (Wolfe and Weissgerber , 2003).
There are computer based systems discussed in this review, that record work postures and
activities either on-site with a computer, or on a videotape that is later analyzed using a
computer. Two options can be used for the observation: time sampling or (simulated) real-time.
The advantages of these systems include the ability to handle posture data in real time and the
avoidance of observer bias, as body movements can be recorded without the presence of an
observer. However, the analysis of the tape-recordings requires a well trained analyst so as to
characterize the work postures correctly. But on other hand, if detailed posture information is to
be obtained, a significant amount of time is required to analyze the data.
4. Blend of Rehabilitation and Ergonomics as a Part of Medical Management
As rehabilitation professionals turn to rehabilitation ergonomics as a specialty, they are
bolstered by the scientific ongoing studies that describe the specifics of programs that have
demonstrated effectiveness. Workers appreciate the ergonomic modifications, assistance with
understanding their capacities and assistance with return to work at the worksite. The work is
positively received by employers as well, since costs and days lost are decreased. The second
positive effect of rehabilitation ergonomics is that re-injury rate can also be measured. In the
1990s, the focus on return to work outcomes became an important area of research.
Pransky, G. et al. (2002) comprehensive review of the literature categorized the variables that
affect return to work. He concluded that the re-injury rates are increased in women with jobs that
have both high pre-injury ergonomic risk and high post-injury ergonomic risk, dissatisfaction
with work accommodation; negative employer reactions, dissatisfaction with the medical
services and dissatisfaction with low back statistics. Staal, 2002 performed a descriptive review
of return to work interventions for low back pain. He noted that multi-model treatment consisting
of exercise, education, behavioral training and ergonomics would be the most promising.
Anema et. al. (2003), studied those with low back pain, acknowledged the use of ergonomics
for prevention and added a study for disability management. When ergonomic suggestions and
interventions were developed for low back pain patients, the results were positive. The
ergonomic interventions were implemented and workers were satisfied with the solutions and
reported that they had a stimulating effect. Loisel et al. (1994) developed the Sherbrooke Model,
which postulated that ergonomic interventions should be used with clinical interventions in
return to work. Another study demonstrated that the occupational interventions, combined with
clinical interventions, saved days on benefits and saved costs Loisel et. al. (2002).
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Lemstra and Olszynski, (2003) evaluated a industry in Canada and demonstrated the
effectiveness of occupational management. This included a physical therapist onsite using
ergonomic reassurance and encouragement to assist injured workers to be on the job safely. The
work was based on the physical and functional information from the physical therapist. The
blending of prevention and return to work ergonomics allowed the intervention to take place
sooner. Upper extremity and back injury claims with the new model demonstrated decrease in
days lost up to 91%. This was superior to the traditional medical model of standard care or a
regime of clinical physical therapy service.
4.1Rehabilitation Ergonomics Components
Rehabilitation professionals have always treated workers with musculoskeletal injuries in
their practice. In the 1980s, worker‘s compensation systems began to strongly emphasize
reduction in work disability. As a result, rehabilitation professionals developed four specialties
that bridge the gap between treatment and return to work. They are:
4.1a.Functional capacity evaluation (FCE)
FCE were developed to evaluate the physical work-related abilities of an injured worker
(Hart et. al. 1993). The impetus came from workers‘ compensation administrators who
determined that physician‘s restrictions alone did not provide adequate specific information for
an employer to bring a worker back to work. Specific work functions were listed and physicians
were asked to rate the worker on each category. In turn, therapists were called upon to develop
an objective means to measure work function that could be used as an adjunct for the medical
release to work. Functional evaluation is an objective measure of the ability of a worker to
perform actual work tasks. FCE adds work relevance to testing by using functional activities
such as lifting, pushing, pulling, carrying, gripping, climbing, walking, balancing, reaching,
sitting, and standing. FCEs utilize the listing of job tasks developed by the U.S. (National
Technical Information Service, Washington DC, 1993).
While functional testing is a specialty for therapists, the resultant findings and
recommendations are stronger when the therapist is also a rehabilitation ergonomist. The
knowledge of the worksite, the jobs and the job modification opportunities provide information
for a stronger resolution of the return to work objective (Marras & Karwowski, 2006).
4.1b.Work rehabilitation
Work-related rehabilitation provides a structured regime that allows the injured worker to
increase function and regain work capabilities whose physical limitations prevent return to work
at their previous job or at full duty. In addition to traditional therapeutic exercise, work
rehabilitation includes actual or simulated work task and work behavior management (Susan J.
Isernhagen, 1988)). Its use of work simulation ensured that work behaviors would be addressed
and that return to actual work would be the goal. An atmosphere is created in which the clients
are responsible for their own progress. The therapist is a guide and assists, but the worker does
the work to accomplish the goals (Marras & Karwowski, 2006).
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In the 1980s Matheson et. al. (1985, 1987) defined and described work hardening. The
Commission on Accreditation of Rehabilitation Facilities (CARF) developed the first work
hardening standards. It defined work hardening as a multi-disciplinary program including
physical, psychological and vocational components. In response to CARF, the American
Physical Therapy Association determined that there were two types of work rehabilitation
programs; work hardening and work conditioning. Work hardening was defined in similar terms
as CARF. Work conditioning emphasizes physical and functional strengthening for return to
work (Marras & Karwowski, 2006).
4.1c.Functional Restoration
Mayer et al. designed a multi-disciplinary program to return chronically injured workers
to the work-place. Objective measurements were emphasized, including those from isokinetic
exercise technology (Mayer et. al.1985).
4.1d.Job modification
At the worksite, modifications match the work to the capacity of the worker to promote
return to work and prevention of re-injury. Both FCE and work rehabilitation focus on the
functional ability of the worker. If a worker has demonstrated capacities to do the essential
functions of his/her job, then the rehabilitation ergonomist provides assurance, answers questions
and facilitates communication with the supervisor and coworkers. If there is not a match,
however, modifications of job tasks are necessary to protect the worker and yet allow essential
functions to be performed productively.
Many modifications are time-limited, as the worker‘s function should improve with
physical work and continuation of the healing process. If a condition is permanent (e.g., spinal
fusion, neurological damage), the modification may also be permanent (Marras & Karwowski,
2006).
4.1e.Early intervention
Immediate intervention when a work injury or illness threatens work ability reduces the
lost time for the worker and increases healing and functional work capability. Thus, innovative
programs were designed to bring an injured worker very early for evaluation and treatment of
their musculoskeletal injuries (Susan J. Isernhagen, 1988, 1995 and Pransky et. al. 2002). Once
the early intervention process is in place, education for workers and supervisors is necessary for
early symptoms of musculoskeletal disorders to be recognized. Workers must be aware of the
early stages of carpal tunnel syndrome, tendonitis, strains, and others, in order for the system to
work.
Intervention includes evaluation of the condition, assessment of current functional capacity to
determine if the worker can continue to work, institution of functional treatment and
modification of the job when early return to work can be accomplished. Early intervention is best
done onsite or in a clinic that is close to the worksite. The effectiveness of early intervention
compared to previous traditional treatment is analysis to identify jobs or job tasks in the
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workplace where problems occur most frequently. The therapist or rehabilitation ergonomist as
part of the team, can then institute prevention measures. These may be ergonomic redesign, new
tools, education, improved job training, stretching, ergonomic postures and problem solving.
Early intervention is a bridge between injury prevention and injury management.
Rehabilitation Ergonomics is still in its early stages, while it gives immense innovative scope
for physiotherapists/physical therapist to act as one. The employers are looking for further better
methods to return injured workers to work, by help of these experts professionals. Early
intervention bridge the gap between return to work and prevention of injury. Job modifications
begin with individual patients and advances into wider use in musculoskeletal injury prevention.
5. Conclusions
The range and scope of the physiotherapist/physical therapist discussed in this review
provide them with ergonomic tools to undertake a range of studies including rehabilitation,
epidemiological, clinical and ergonomic research, evaluation of ergonomic programs and design
interventions, surveillance of workplace ergonomic hazards, and the detection and quantification
of exposures to adverse workplace physical ergonomic stressors. Armed with this battery of
tools, the physiotherapist with the knowledge of ergonomics will be well positioned to
systematically tackle a wide range of rehabilitation and clinical issues to further implement
effective solutions to the problems that are uncovered.
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