Author: Tealey, William, P. Title: Ergonomic Analysis of the Coil Winding Processes at Company XYZ The accompanying research report is submitted to the University of Wisconsin-Stout, Graduate School in partial

completion of the requirements for the

Graduate Degree/ Major: MS Risk Control

Research Adviser: Brian Finder, D.I.T.

Submission Term/Year: Spring, 2012

Number of Pages: 127

Style Manual Used: American Psychological Association, 6th edition

D I understand that this research report must be officially approved by the Graduate School and that an electronic copy of the approved version wm be made available through the University Library website D I attest that the research report is my original work (that any copyrightable materials have been used with the permission ofthe original authors), and as such, it is automatically protected by the laws, rules, and regulations of the U.S. Copyright Office. D My research adviser has approved the content and quality ofthis paper.

STUDENT:

NAME DATE:

ADVISER:

1. CMTE MEMBER'S NAME: DATE:

2. CMTE MEMBER'S NAME: DATE:

3. CMTE MEMBER'S NAME: DATE:

This section to be completed by the Graduate School This final research report has been approved by the Graduate School.

Director, Office of Graduate Studies: DATE:

2

Tealey, William P. Ergonomic Analysis of the Coil Winding Processes at Company XYZ

Abstract

The collected data from the various methods used in this ergonomic analysis suggest the

presence of numerous potential loss exposures involved in the task of manually handling the

copper wire taper packs at Company XYZ. The comparison of data collected in this ergonomic

analysis with various literature presented in Chapter II, presents an apparent relationship between

the discomfort and injuries that employees have incurred. The awkward postures in combination

with the use of excessive force to lift the taper packs are two of the risk factors that may

contribute to the development of work-related musculoskeletal disorders. Based on the evidence

presented in the collected data, the identification of past injuries, the review of feedback from the

employee discomfort survey, and present risk factors, it is plausible to conclude that ergonomic-

based issues with the potential for impending loss are present in the manual handling task for

copper wire taper packs. In consideration of the conclusions presented by this ergonomic

analysis and the hierarchy of risk controls delineated in the literature review, a selection of

engineering and administrative controls are recommended to minimize the loss exposure from

ergonomic-based risk factors associated with the manual material handling of copper wire taper

packs.

3

Acknowledgments

I would like to thank my family, close friends, and classmates for the assistance and

support they have provided to me over the past year and a half of my graduate studies. In the

absence of a strong framework of support, I would not have been able to accomplish everything

that I have. A special thank you to my wife, Sara, and my kids, Eric, Sawyer and Sami; without

their understanding and support during many hours spent away at college or studying, this entire

process would not have been possible.

I am truly thankful to my research advisor, Dr. Brian Finder, whose encouragement,

guidance and support, from my initial application into UW -Stout's Graduate Risk Control

Program, through the arduous and stressful course load, to the finalization of my thesis, has

allowed me to gain a fuller appreciation for the continually evolving field of risk control. His

caring attitude, along with his expertise in the field, has enabled and propelled many students,

including myself, to reach their goal of attaining a management position in the risk control field.

Additionally, I want to thank Dr. Renee Surdick with the Northwestern Wisconsin

Manufacturing Outreach Center and the company where I completed my ergonomic analysis

research and associated thesis. It was through their culture of continuous process improvement,

with an emphasis on safety, that I was able to complete this project. The motivational support

and assistance was greatly appreciated.

4

Table of Contents

.................................................................................................................................................... Page

Abstract ............................................................................................................................................ 2

List of Tables ................................................................................................................................... 8

Chapter I: Introduction .................................................................................................................... 9

Purpose of the Study .......................................................................................................... 12

Goals ofthe Study .............................................................................................................. l2

Background and Significance ............................................................................................ 13

Assumptions of the Study .................................................................................................. 14

Limitations ofthe Study ..................................................................................................... 14

Definition ofTerms ............................................................................................................ 14

Chapter II: Literature Review ........................................................................................................ 19

History of Industrial Ergonomics ....................................................................................... 19

Cumulative Trauma Disorders ........................................................................................... 21

Causes of Cumulative Trauma Disorders .......................................................................... 22

Common Types of Cumulative Trauma Disorders ........................................................... .24

Muscle and Tendon Disorders ............................................................................... 25

Tunnel Syndromes ................................................................................................. 26

Nerve and Circulation Disorders ........................................................................... 27

Costs Associated with Work-Related Musculoskeletal Disorders ..................................... 28

Direct costs ............................................................................................................. 29

Indirect costs .......................................................................................................... 3 0

5

Manual Material Handling Issues ...................................................................................... 33

W orksite Analysis .............................................................................................................. 3 5

Ergonomic Analysis Tools ................................................................................................. 37

Rapid Upper Limb Assessment .............................................................................. 3 8

Rapid Upper Body Assessment .............................................................................. 39

Revised NIOSH Lifting Equation .......................................................................... .40

Ergonomic W orksite Assessment .......................................................................... .40

Risk Control Methods Hierarchy ....................................................................................... .41

Engineering Controls .............................................................................................. 43

Administrative Controls ......................................................................................... .46

Personal Protective Equipment .............................................................................. .48

Summary ............................................................................................................................. 50

Chapter III: Methodology , ............................................................................................................. 51

Subject Selection and Description ..................................................................................... 51

Instrumentation .................................................................................................................. 51

Data Collection Procedures ................................................................................................ 52

RULA Data Collection Procedures ................................................. , ...................... 53

REBA Data Collection Procedures ........................................................................ 54

Revised NIOSH Lifting Equation .......................................................................... 56

Liberty Mutual Manual Material Handling Tables ................................................ 57

Goniometer ............................................................ , ............................................... 59

Electronic Scale ..................................................................................................... 59

6

Employee Discomfort Survey ................................................................................ 59

Ergonomic Risk Factor Checklist .......................................................................... 60

Videotaping ............................................................................................................ 61

Review of Available Records ................................................................................ 62

Data Analysis ..................................................................................................................... 62

Limitations ......................................................................................................................... 63

Chapter IV: Results ........................................................................................................................ 64

Collected Data ................................................................................................................... 65

Goal Number One .................................................................................................. 65

REBA ......................................................................................................... 65

RULA ......................................................................................................... 67

Revised NIOSH Lifting Equation .............................................................. 68

Liberty Mutual MMH Tables ..................................................................... 70

Goal Number Two ................................................................................................. 72

Video Postural Analysis ............................................................................. 72

Employee Discomfort Survey .................................................................... 7 4

Ergonomic Risk Factor Checklist .............................................................. 77

Review of OSHA 300 Log ......................................................................... 81

Discussion .......................................................................................................................... 82

Chapter V: Conclusions and Recommendations ............................................................................ 91

Limitations ......................................................................................................................... 92

Major Findings ................................................................................................................... 92

7

Conclusions ........................................................................................................................ 93

Recommendations .............................................................................................................. 96

Engineering Controls ............................................................................................. 96

Administrative Controls ....................................................................................... 1 00

Areas ofFurther Research ............................................................................................... 102

References .................................................................................................................................... 1 03

Appendix A: RULA Survey ......................................................................................................... l13

Appendix B: REBA Survey ......................................................................................................... 114

Appendix C: Revised NIOSH Lifting Equation Worksheet.. ..................................................... .! IS

Appendix D: Liberty Mutual Manual Material Handling Tables ................................................ 116

Appendix E: Employee Discomfort Survey ................................................................................ 118

Appendix F: Ergonomic Risk Factor Checklist ........................................................................... 120

Appendix G: OSHA 300 Log ...................................................................................................... 125

Appendix H: UW-Stout Implied Consent Statement.. ................................................................. l26

8

List of Tables

Table 1: REBA Assessment Scoring Table ................................................................................... 66

Table 2: RULA Assessment Scoring Table ................................................................................... 68

Table 3: Measurements for use in the Liberty Mutual Manual Material Handling Table ............. 71

Table 4: Employee Discomfort Survey Levels for Body Regions ................................................ 75

Table 5: Causes of Employee Discomfort ..................................................................................... 76

Table 6: Final Three Questions on the Employee Discomfort Survey .......................................... 77

Table 7: Manual Material Handling Related Injuries and Illnesses, 2006-2010 ........................... 82

9

Chapter I: Introduction

Ergonomics, also known as biotechnology, human engineering, and human factors

engineering, is the science of designing equipment in the workplace environment, in order to

minimize employee illnesses or injuries (Kahn, 2004). According to the International

Ergonomics Association ("What is Ergonomics", 2000), the official definition of ergonomics is:

the scientific discipline 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. (par. 1)

Therefore, ergonomics refers to the analysis of work-related factors that may potentially lead to a

risk of musculoskeletal disorders (MSDs) and the development of practices to eliminate or at

least reduce their severity. A variety of ergonomic risk factors can be associated with work

environments that utilize repetitive, forceful, or prolonged exertion of the hands; frequent or

heavy lifting, pushing, pulling, or carrying of heavy objects; and prolonged awkward postures

(Occupational Safety and Health Administration [OSHA], 2007). The intensity, frequency, and

duration of the exposure to these types of working conditions, will invariably determine the

extent or degree of risk that an employee encounters in the completion of one's job description

(OSHA, 2007).

Musculoskeletal disorders are injuries and illnesses which involve the muscles, nerves,

ligaments, tendons, joints, cartilage and spinal disk. In 2007, MSDs were attributed to 29 % of

all working environment injuries that culminated with time away from work (US Department of

Labor, 2007). Well researched ergonomic interventions can lower the physical demands of

10

manual material handling (MMH) work tasks, thereby reducing the incidence and severity of the

musculoskeletal injuries they can cause (Putz-Anderson, 1988). A major cause behind work

injuries requiring compensation are those tasks that include some type of manual materials

handling; whether it takes the form of lifting, placing, carrying, holding or lowering. A Bureau

of Labor Statistics (BLS) survey indicated that four out of five of these injuries were to the lower

spine, and that three out of four occurred while the employee was lifting (Back injuries guide,

2011). The potential that ergonomic interventions have for reducing injuries and their related

costs can make them an extremelyuseful tool for improving a company's productivity, product

quality, and overall bottom line.

MSDs promote situations where not only does the individual suffer, but also varying

aspects in the economy due to associated worker compensation costs. The National Research

Council has reported to the U.S. Senate that MSDs of the lower spine and upper extremities

affect an estimated one million workers per year causing lost time from work, and thereby

present a very real national health crisis (Barondess, 2001). It has been proposed that

approximately $50 billion in work-related expenses are being incurred by the United States as a

result of the occurrence ofMSDs; which computes to a startling 1 % ofthe Gross Domestic

Product (Barondess, 2001). Exposure to workplace hazards place employees at risk from

personal suffering and possible loss of employment and income. The associated MSDs may

cause companies to lose efficiency through employee absenteeism, and on a national level, they

can contribute to the government's increases in social security costs ("Some jobs increase,"

2001).

11

Injuries to the spine are one of the most prevalent and costly work-related

musculoskeletal disorders in the United States. In 1998, more than 440,000 people missed work

for at least one day due to a spinal injury, accounting for one quarter of all nonfatal

injuries/illnesses causing people to be absent from work (Pubh 5120, 2011). MSDs have

developed into a world-wide problem that needs to be addressed and based on current trends,

they are expected to increase dramatically in coming years (Pubh 5120, 2011).

Employers are often faced with the tradeoff between efficiency and productivity versus

employee safety and comfort. The good news is that there does not have to be a tradeoff

between a company's profitability and an employee's health. Rather, quality ergonomic

assessment and remedial design can result in improved efficiency and productivity. An

employees' time away from work due to injury reduces productivity, poorly designed equipment

and procedures reduces efficiency, and violation of regulatory requirements can certainly affect

the bottom line. Therefore, by the creation of an ergonomically beneficial workplace, employee

safety will be enhanced while the company increases its efficiency and productivity at the same

time ("Leading practices for," 2007).

Company XYZ is a family owned and operated light manufacturer located in Northern

Wisconsin. Since the company's establishment, they have specialized in producing custom

transformers and inductors. In order to produce the transformers, large shipments of copper coil

are utilized in different size or gauge of wire, and in varying quantities. The most common

supply of copper wire received by Company XYZ comes on spools in cardboard boxes called

taper packs; weighing approximately 70-90 pounds apiece. Shipments of the copper coil taper

packs are delivered to the company on pallets. It is from this stage of arrival through the process

12

ofwinding the copper wire onto new transformers that the employees complain of physical

distress. This distress may be associated with exposure to the potential material handling-based

risk factors as they maneuver copper coil taper packs back and forth from storage to staging

areas for the copper coil unwinding/winding process.

According to the President and the Operations Coordinator of Company XYZ, employees

are educated in lean manufacturing techniques as well as involved in decisions related to

manufacturing layout and production flow. Company XYZ is committed to maintaining their

culture of caring about employees, customers, and products at the highest level. The light

manufacturing company has transformed their culture from one of command and control to one

of continuous improvement, employee involvement, and lean manufacturing principles. As a

result of Company XYZ' s corporate culture there is a strong interest in determining the causes

for injury or illness within the coil winding/unwinding process and ultimately eliminating or

reducing such potential. Therefore, the current manual material handling practices of the coil

wire taper packs are placing Company XYZ at risk for experiencing significant employee injury

and other productivity related losses.

Purpose of the Study

The purpose of this study is to analyze the manual material handling requirements that

are associated with the set-up and change-over of copper wire spools.

Goals of the Study

The goals of this study include the following:

13

Assess the current ergonomic requirements involved in the coil unwinding process/set-up

and/or maintenance when moving, loading, and unloading material rolls of copper wire

coils in taper packs using the REBA, RULA, revised NIOSH Lifting Equation, and the

Liberty Mutual MMH tables.

" Perform video postural analysis, review the results of an employee discomfort survey,

complete an ergonomic risk factor checklist, and review OSHA 300 logs to better

quantify the extent to which various risk factors are or are not present.

Background and Significance

An ergonomic analysis of the manual material handling of wire taper packs during the

copper wire unwinding/winding processes at Company XYZ is essential for the identification of

ergonomic issues which could lead to work-related musculoskeletal disorders (WMSD).

Company XYZ has not yet suffered significant losses from the manual material handling of

copper wire taper packs. However, if ergonomic risk factors are present and proactive measures

are not instituted, the likelihood for injuries to workers may become a significant loss exposure.

If a WMSD injury does occur, Company XYZ will incur direct costs plus indirect costs. The

direct costs could be medical and indemnity payments, while the indirect costs could be payment

for overtime, decreased employee morale, lost production, or missed production schedules.

Company XYZ is cognizant that the manual handling of taper packs may present potentially

inherent ergonomic risk factors and prefers to eliminate or reduce the potential for this hazard

exposure before the workers become symptomatic. This analysis, in effect, is a preventative

measure necessary to avoid or reduce the risk of any WMSDs or injuries, legal issues, quality

14

issues, or financial issues that may occur on the copper wire unwinding/winding production lines

at Company XYZ.

Assumptions of the Study

1. Answers given by Company XYZ employees are honest and accurate.

2. Any reported injuries, pains, and other discomfort are directly related to the

process of winding/unwinding/set-up and/or maintenance of the copper wire coils.

Limitations of the Study

This study is limited only to manual material handling tasks required by activities

completed during the wire coil winding/unwinding processes. No considerations are made to

any actions or conditions outside this specific job task. The study is only for the purpose of

identifYing problem areas in the job task and offering solutions to reduce the potential for

injuries to employees. Areas that present the greatest potential for improvement will be

addressed only, as long as no adverse effects to job performance are realized from the proposed

improvement.

Definition ofTerms

Administrative Control. "Procedures and methods set up by the employer, which

significantly reduce exposure to risk factors by altering the way in which work is performed;

examples include employee rotation, job task enlargement, and adjustment of work pace"

(Kearney, 2008, p.295).

Anthropometry. The study which encompasses the physical dimensions, proportions,

and composition of humans including the study of any associated variables affecting them

(Strarnler, 1992)

15

Awkward Posture. "Posture is the position of the body while performing work activities.

Awkward posture is associated with an increased risk for injury. It is generally considered that

the more a joint deviates from the neutral (natural) position, the greater the risk of injury"

(Kearney, 2008, p.296).

Cumulative Trauma Disorders (CTDs). The health disorder arising from the excessive

use of a particular joint or tissue, accumulated over an extended period of time (MacLeod, 1995).

Duration. "The continuous time a task is performed without a sufficient rest period"

(Kearney, 2008, p.296). It can be measured as the minutes or hours per day the worker is

exposed to a risk. Duration can also be viewed as the years of exposure to a risk factor. In

general, the greater the duration of exposure to a risk factor, the greater the degree of risk.

However, specific duration guidelines have not been established for risk factors such as force,

posture and repetition.

Engineering Control. Reducing exposure to risk for workers through the application of

physical changes to jobs or products (Chengular, Rodgers, & Bernard, 2004). Engineering

controls operate on the source of the risk and prevent or reduce employee exposure to that risk.

Examples might include use of a lighter weight part or inclusion of a work surface with variable

adjustment.

Ergonomics. The science of designing the work environment to accompany the

individual, rather than the opposite. Ergonomics dissolves barriers to quality, productivity, and

safe human performance by fitting products, tasks and environments to people" (Ergoweb,

2011).

16

Ergonomics program. "Application of ergonomics in a structured system including the

following components: health and risk factor surveillance, job analysis and design, medical

management, and training" (Kearney, 2008, p.297).

Force. The amount of physical exertion placed on an object in order to change its speed

or motion. Usually, the greater the physical force applied, the greater the exposure of risk to a

worker (Stramler, 1992).

Goniometer. A tool used for measuring the angles of human joints that consists of a

minimum of two arms, with one that has a center pivot point (Stramler, 1992)

Human Factors. "A term synonymous with 'ergonomics', it is the branch of this science

that began in the U.S. and focuses on cognitive performance ofhumans" (Kearney, 2008, p.298).

Incident Rate. The number of injuries or illnesses that happen over a length of time,

most frequently reported as the number of incidents per 200,000 worker-hours (Kearney, 2008).

Manual Materials Handling (MMH). Manual materials handling refers to any handling

task that does not rely on the assistance of machines or equipment, but instead involves only the

worker as the source of power (Stramler, 1992). MMH may encompass any or all ofthe

following: lifting, lowering, pushing, pulling, carrying, and holding. (Kearney, 2008).

Musculoskeletal Disorders (MSD). Injuries and disorders of the muscles, nerves,

tendons, ligaments, joints, cartilage and spinal disc that appear slowly, from exposure to

contributing factors, during an extended period (Tayyari, & Smith, 1997). They, therefore, are

also synonymous with cumulative trauma disorders.

Occupational Illness. "Any abnormal condition or disorder, other than one resulting

from an occupational injury caused by exposure to factors associated with employment" (Kahn,

2004. p.236). It includes acute and chronic illnesses or disease which may be caused by

inhalation, absorption, ingestion or direct contact.

17

Occupational Injury. Any injury such as a cut, fracture, sprain, etc., which results from

a work-related event or from a single acute exposure in the work environment (Kahn, 2004).

Injuries or disorders that can be related to work include Carpal tunnel syndrome (CTS), De

Quervain's disease, trigger finger, sciatica, epicondylitis, tendinitis, Raynaud's disease, and

herniated spinal disk (Kearney, 2008).

Occupational Safety and Health Administration (OSHA). The mission of OSHA is to

save lives, prevent injuries, and promote safe and healthful working environments in the United

States (Kahn, 2004). Federal and state governments work in cooperation with the millions of

workers and their respective employers who are regulated by the Occupational Safety and Health

Act of 1970 (Keamey, 2008).

OSHA 300 Log. A record that employers must maintain to list and delineate

occupational injuries and illnesses, and document the pmiiculars of each work-related incident

(Kearney, 2008).

Recovery Time. The time needed for rest between physical exertion periods is called

recovery time and these short breaks from work can relieve associated pain and stress (Kearney,

2008). Insufficient rest periods between the physical work often leads to a reduction in a

worker's ability to perform. As the length of time that the uninterrupted work increases, so will

the corresponding amount of recovery time required.

Repetition. The number of repetitive motions utilized to complete a job task is repetition

(MacLeod, 1995). Repetitive motion in excess has been associated with injury and worker

18

discomfort, as well as inefficient use of a worker's time. Due to the risk of debilitating injury,

repetition should be avoided or at least reduced.

Risk Factors. Circumstances in any job or work task that increase the potential of risk to

acquire cumulative trauma disorders (Goetsch, 2008). "Risk factors are regarded as synergistic

elements of ergonomic hazards that must be considered in light of their combined effect in

inducing CTDs" (Kearney, 2008, p.301).

Sprain. A sudden or forceful bending of a joint that leads to the over-stretching or tearing

ofligaments (Tayyari, & Smith, 1997). The result of a sprain is often discerned by swelling or

inflammation, and sometimes discoloration.

Strain. If a muscle, ligament, or tendon is stretched beyond its normal limits, it is called a

strain (Tayyari, & Smith, 1997). This type of injury may be a direct result of heavy lifting or

exertion in opposition to an outside force, usually accompanied by sudden, unusual, or

unaccustomed movement.

Supination. Movement of the forearm that places it in a position with the palm of the

hand facing skyward or away from the body (Kearney, 2008).

Work Related Musculoskeletal Disorders (WMSD). "Injuries and disorders of the

muscles, nerves, tendons, ligaments, joints, cartilage and spinal disc due to physical work

activities or workplace conditions in the job" (Kearney, 2008, p.303). Some specific injuries

would include carpal tunnel syndrome, Golfer's or Tennis elbow, Ganglionic cyst, bursitis,

Trigger finger, tension neck syndrome, and degenerative disk disease.

19

Chapter H: Literature Review

The purpose of this study was to analyze the ergonomic requirements that are associated

with the set-up and change-over processes of copper wire spools at Company XYZ. The current

manual material handling practices of the coil wire taper packs are placing XYZ Company

employees at risk for experiencing musculoskeletal injuries. These potential work-related

musculoskeletal disorders may result in significant costs with associated productivity loss.

Chapter II illustrates the magnitude of the cost and the complexity of the associated risks with

unresolved ergonomic issues in the work environment. The literature review will include the

following topics as related to this study: history of industrial ergonomics, cumulative trauma

disorders, aspects involved in an ergonomic analysis, common types of cumulative trauma

disorders and associated costs, material handling issues, worksite analyses, types of tools used to

analyze work environments, and risk control methods used to prevent and/or reduce the potential

for loss in the workplace.

History of Industrial Ergonomics

The term ergonomics is derived from the combination of two Greek words: ergos,

meaning work, and nomos, meaning the study of. For simplicity, it refers to the study of work.

The association between workers and musculoskeletal injuries was documented centuries ago

and one of the first researchers in the field of ergonomics, Wojciech Jastrzebowski, originally

coined the term in an 1857 Polish newspaper (Salvendy, 1997). Ergonomics therefore, has often

been articulated as the practice of designing the job to fit the worker, rather than forcing the

worker to fit the job.

20

A number of important researchers throughout history have contributed significantly to

the study of work environments and their direct relationship to a worker's health and wellness,

with one such individual being Bernardino Ramazinni. This early ergonomics author published a

book in 1713, The Diseases of Workers, which described an association between the onset of

certain cumulative trauma disorders in workers and the work they were being asked to perform

(Ramazinni, 2001 ). Another early visionary in ergonomics was Frederick Taylor. The Industrial

era of the early 1900s was still largely propelled by raw human capability and ideas were being

created at a rapid pace to enhance a worker's abilities. Taylor devised a concept to increase a

worker's productivity by minimizing the number of steps it took to complete their job task which

became known as Scientific Management. Also, through the creativity of Frank and Lillian

Gilbreth, two more early researchers, a time motion analysis method was developed. This

method promulgated the standardization of work materials, tools and the individual processes

associated with various work environments by increasing efficiency and decreasing the fatigue

factor (Ergoweb, 2011).

The proliferation of ergonomics, also known as human factors engineering, did not come

to fruition until World War II (Stellman, 1998). The technology explosion caused by the war,

prompted heightened interest in the interface between humans and machines. It was the research

and development of highly engineered and costly military equipment that placed a spotlight on

design problems. The field of ergonomics evolved through the focused interest on engineering

and design in matching the servicemen to the machines through integration with the tasks they

were performing (Salvendy, 1997). The focus of attention after World War II was greatly

influenced by the exponential growth rate of industry and the need for greater productivity from

21

the workforce (Stellman, 1998). This focus of concern later expanded, due to the change in

worker roles with advancing technology, around the 1960s and early 1970s to include worker

safety. A variation of studies began to arise from this focus to include, the maximum load that

can be pulled, pushed, or carried, the requirement of muscle force in the completion of manual

tasks, the force of compression on the lower back when lifting, and a person's heart rate as it

relates to the performance of labor intensive work (Ergo web, 2011 ). Types of studies and

knowledge that was related to organizational design, workers cognitive process when making

decisions, and how design implementations are perceived by workers evolved into cognitive

ergonomics or what is better known as human factors (Bridger, 2009). Alternate pathways of

knowledge including working environment's physical attributes and the worker abilities such as

lifting force, vibratory sensation, and reach limits became known as ergonomics or industrial

ergonomics (Bridger, 2009).

Cumulative Trauma Disorders (CTDs)

A cumulative trauma disorder (CTD) is an inclusive term used to describe injury and

trauma of the soft tissue including muscles, tendons, ligaments, joints, cartilage, and also the

central nervous system (Vincoli, 2000). It can also be referenced as, either a musculoskeletal

disorder, repetitive motion injury, repetitive stress injury, or an occupational overexertion

syndrome. These types of diseases, in opposition to common opinion, are not caused by

immediate accidents that overstretch or strain muscles, but instead slowly mature from

repetitious micro-trauma (Putz-Anderson, 1988). Painful and often disabling injuries or illnesses

are very often chronic in nature and develop gradually over weeks, months, and even years.

CTDs affect the upper body, with focus on the back and arms, to a greater extent than other areas

22

of the human anatomy (Tayyari, & Smith, 1997). This type of trauma can cause a variety of

symptoms including pain, numbness, tingling, stiff joints, difficulty moving, and inflammation of

soft tissue (Putz-Anderson, 1988). CTDs usually result from exposure to multiple risk factors

that are involved with working conditions causing the disorders, and not simply resulting from a

single event such as a slip, trip or fall. CTDs, therefore, are any disorders realized when the

human body tries to overcome repeated forces placed on certain body parts through the issuance

ofvarious signs and symptoms (Daugherty, 1999).

Causes of CTDs

The occurrence of CTDs may be attributed to three major ergonomic risk factors that

include awkward postures, excessive forces, and highly repetitious movements (Tayyari, &

Smith, 1997). The ability ofthe human body to heal itself is immense ifthe time for recovery is

adequate. However, workers will experience an increased risk ofCTDs if this time is inadequate

and if awkward, forceful postures are involved with movements of a repetitive nature (Putz-

Anderson, 1998). The three ergonomic risk factors of awkward posture, excessive force and

repetitive movement then, are the most significant contributors to CTDs.

Awkward or extreme postures are most easily defined as those that are not neutral and

efficient postures for the human anatomy (Parker, & Imbus, 1992). These types of worker

postures cause a reduction in the body's ability to re-position itself in order to utilize the muscles

most beneficial for the task. When the lower extremities are out of alignment, this can cause a

domino effect for the upper extremities. That is, the upper extremities are forced to compensate

for the awkward posture which places undue strain on them. This type of body re-alignment can

23

be witnessed when employees are rotating their trunks, over-extending the reach envelope, and

flexing or extending at too great of a degree (Parker & Imbus, 1992).

Force is the physical exertion which is imparted on a material, tool, or work surface by a

worker in the completion of a task (Vincoli, 2000). The exertion of pushing or pulling on an

object will cause movement, a change in speed, or a change in direction. The amount of effort or

force exerted by a worker depends on the weight of object being handled, the gripping ability,

the body posture, and the speed ofthe worker's movement (DiBerardinis, 1999). The force

needed in the performance of a job is created through the body's muscles, and in perfect

conditions, the muscles will generate ample force for most manual material handling functions

(Parker & Imbus, 1992). However, if the ability of the muscles can not generate the force

needed for the task, three serious scenarios can transpire. The first is that the muscle's power is

less than the force demand, but because of the worker's tenacity or specific job specifications,

the task is undertaken anyway. The cumulative effect is an acute muscle strain listed as an

overexertion injury. Secondly, is that the muscle's power is again less than the force demand,

but this time the task is undertaken by struggling with excessive activity. The additional activity

needs the help of extra joints and muscles to complete the task, which utilizes more energy,

speeds up fatigue, and imposes a poor performance. The last scenario is that the force demand is

equal to more than 50% of the muscle's ability. In this case, the muscle can perform the task, but

the labor consumes such a large portion of its ability that it depletes the energy reserve for future

tasks (Parker & Imbus, 1992). According to Putz-Anderson (1988), the increase of efforts by

muscles in performing particular tasks directly correlates to a corresponding decrease in blood

circulation causing the muscles to fatigue faster. It is this correlation between the workers use of

24

excessive force and the decrease in blood supply which will elevate the potential to evolve CTDs

(Tayyari, & Smith, 1998).

Repetitive work is defined as a task or work activity that, over some duration of time, is

repeated without interruption (Vincoli, 2000). Weariness of the muscles will eventually happen

as a result of repetitive movements. Parker and Imbus (1992) believe that repetition has been

inappropriately labeled as the most important causative factor in CTDs. Repetitive motion

injuries, the initial term given to CTDs, implies repetition as the leading cause of development.

However, Parker and Imbus conclude that it is the combination of repetition with force that is the

most important predictor of the occurrence of CTDs. Completion time for a unit or cycle of

work is often less than a few minutes in many production facilities, and if this cycle is

continuous for greater than two hours, it is repetitive in nature (Chengular, Rodgers, & Bernard,

2004). A tasks repetitive nature is greatly influenced by production or automation pacing

incentive programs, piece work, and unrealistic schedules. In association with poor postures and

excessive force, repeated movements become more likely to promulgate risk exposure.

Although, even with forces of smaller variation, high frequencies of repetition can contribute to

the onset of cumulative trauma disorders (Tayyari, & Smith, 1997). It is the contributory

association from the ergonomic risk factors of posture, force, and repetition that promulgate and

enhance various types of CTDs in the workplace.

Common Types of CTDs

CTDs go by many different names such as repetitive strain injuries (RSis) and work-

related musculoskeletal disorders (WMSDs), as well as by the specific diagnoses. They are

caused by the presence of one or more ergonomic risk factors such as force, posture, repetition,

25

and vibration. The main types of CTDs can be separated into various disorders depending on the

body part being affected. Muscle and tendon disorders, tunnel syndromes, and nerve and

circulation disorders are the three broad classifications ofCTDs (Goetsch, 2008).

Muscle and tendon disorders. Ailments which involve the muscle and tendons most

often affect the connections to the bones via the tendons. Tendon disorders occur when these

rope-like structures rub, either at or near the joint, against a ligament or bone resulting in most

instances with a faint aching sensation felt over the tendon (Putz-Anderson, 1988). Symptoms

also include sensitivity to the touch and uneasiness in the performance of work-related functions.

Even though minor tendon disorders occur often, the cause of the malaise should be treated or

eliminated so that the condition does not become more serious. Common upper extremity

tendon disorders include tendinitis, tenosynovitis, ganglionic cyst, and epicondylitis (Tayyari &

Smith, 1997).

Tendinitis is an inflammation of a tendon often caused by repetitive motions, minor

impact on a specific area, or from a sudden serious injury (Kahn, 2004). Repeated stimulation of

a tendon that has become swollen may lead to tearing or fraying of the tendon fibers themselves

resulting in weakening of the tendon and the possibility of permanent damage (Putz-Anderson,

1988). Poor posture, improper stretching or conditioning, and natural aging all contribute to a

person's risk for developing tendinitis (WebMD, 2011).

Tenosynovitis is a CTD of the tendon created by swelling of the synovial sheath which

encompasses it and provides it lubrication for movement via the synovial fluid (Vincoli, 2000).

Movement is hampered as the exterior of the tendon develops irritation and irregularity. Chronic

tenosynovitis is commonly referred to as stenosing tenosynovitis and can occur as two different

26

types which are DeQuervain's disease and flexor tenosynovitis (Goetsch, 2008). DeQuervain's

disease occurs at the connection between the wrist and thumb and contributes to pain upon

movement. Flexor tenosynovitis, also called trigger finger, happens when a hand digit gets stuck

in a bent position (Goetsch, 2008).

A ganglionic cyst or ganglion is another tendon disorder which has the appearance of a

hernia-like projection nearby the afflicted joint (Tayyari, & Smith, 1997). The tendon sheath

accumulates synovial fluid, which causes a swelling or bump under the skin, often on the wrists.

Ganglionic cysts most commonly occur on the back of the hand, at the wrist joint and can be

associated with mild discomfort to no pain at all (Putz-Anderson, 1988).

Epicondylitis usually occurs in two forms known as medial or lateral epicondylitis. It is

an inflammation in the region of the epicondyle which is a bony extension at the distal end of

various bones (Stramler, 1992). Medial epicondylitis, known as golfer's elbow, presents itself as

a disturbance of the tendon attachments to the finger flexor muscles on the interior portion of the

elbow (Putz-Anderson, 1988). Golfer's elbow can be quite painful when inflammation occurs on

the ulnar side of the elbow, where the tendons of the forearm muscles attach to the bone.

Similar to golfer's elbow is lateral epicondylitis, known as tennis elbow, but it occurs on the

radial side ofthe elbow (WebMD, 2011). Workers who clench their fingers repetitively with a

substantial amount of force have the possibility to acquire either of these disorders.

Tunnel syndromes. Tunnels are created by ligaments and other soft tissue and are the

basic pathways for the nerves (Goetsch, 2008). Radial, median, and ulnar nerves proceed

through tunnels in the foream1 and wrist, and injury to these areas can cause irritation that places

pressure on the nerves. The pressure on the nerves, such as pinching, rubbing, repetitive

27

motions, or even from swelling, can cause nerve disorders (Karwowski, & Marras, 1999). Some

tunnel syndromes are carpal tunnel syndrome, radial tunnel syndrome, cubital tunnel syndrome,

sulcus ulnaris syndrome, and Guyon's canal syndrome. The most recognized of these syndromes

is carpal tunnel syndrome. The carpal tunnel receives its name from eight bones, called carpals,

which form a tunnel-like structure in the wrist. The clenching power of the hand and fingers is

compromised in carpal tunnel syndrome (CTS) because of injury that compresses the median

nerve (Stramler, 1992). Symptoms of this disorder may include pain, numbness, or tingling in

hands and wrists, especially in the thumb, index and middle fingers and become quite severe

while sleeping (Putz-Anderson, 1988). CTS is sometimes called a repetitive stress injury (RSI)

due to its commonality to some types of occupations which expose the wrist to extreme angles of

movement away from the neutral position (Kahn, 2004). These extreme angles are caused by

repetitive flexion, extension, ulnar deviation, and radial deviation of the wrist, which may

regularly occur during work-related processes.

Nerve and. circulation disorders. Nerve and circulation disorders or neurovascular

disorders involve both the blood vessels and the nerves (Putz-Anderson, 1988). One ofthe most

common neurovascular disorders that affects the shoulder and upper arm is the thoracic outlet

syndrome. Thoracic outlet syndrome occurs with a feeling of numbness of pain in the arm

caused by compression of blood vessels and nerves that enter the arm near the scalenus anterior

muscle (Stramler, 1992). The symptoms of this disorder are analogous to that of carpal tunnel

syndrome in that there is potential for numbness or tingling in the arms and fingers, and a weak

pulse in the wrist could be observed (Putz-Anderson, 1988). Another common neurovascular

disorder in which the blood vessels in the hands are compressed is called Raynaud's disease or

28

vibration syndrome (Goetsch, 2008). Recurring events offmger blanching, where the finger

turns white, characterizes this syndrome as a result of total closure of the digital arteries (Putz-

Anderson, 1988). The condition is caused partially by the extreme force used to grasp tools and

the extended utilization of vibrational equipment such as pneumatic drills or chain saws.

Costs Associated with WRMSDs

It is possible that few individuals in the private as well as the public sectors possess a true

understanding of the extent of loss that a poorly designed workplace can cause to a nation. The

United States incurred an estimated cost of $849 billion annually, from the years 2002 to 2004,

for the treatment of all workers diagnosed with a musculoskeletal disease plus the corresponding

indirect lost wages (Jacobs, 2008). This figure represents a staggering 7.7% ofthe gross

domestic product of the United States. Approximately 2.4 million people are employed in

Wisconsin and in 2003, the Bureau of Labor Statistics estimated that 137,000 Wisconsin workers

were injured on the job or became ill as a result of exposure to hazardous conditions at work

("Table 7: number," 2003). WMSDs result in substantial human and economic costs not only for

the workers and employers, but also the government. Wisconsin worker compensation claims

filed in 2004 totaled 36,699 with a compensable cost of almost $238 million ("Research and

statistics," 2005). Total Wisconsin direct and indirect costs ofWMSDs likely exceed $1 billion

annually. Worker compensation claims for the United States were reported by the National

Academy of Social Insurance as about $58 billion in 2009 (Sengupta, Reno & Burton, 2011). It

is the increasing accumulation of data that is providing direct evidence of the escalating costs of

WMSDs and correlation with inadequately designed working environments.

29

Based on nationally available data, it is estimated that direct and indirect costs of

WMSDs in the U.S. exceed $170 billion annually. The multitude of costs that can be directly

equated to the poor design of working environments, largely influence a company's ability to

survive and prosper (MacLeod, 1995). Ergonomics, in its purest form, can aid in the reduction

of these expenses and be an asset that enables a business to be competitive. Most costs in the

workplace, such as workers compensation premiums and/or losses, are often viewed by those in

charge as a required expense of daily business operations and totally outside of management's

ability to change (MacLeod, 1995). However, the truth is that the majority of these expenses can

be reduced or even negated by the application of ergonomic programs (MacLeod, 1995). The

various costs that often accompany inadequate usage of proper ergonomic principles, concepts

and values are usually separated into two sections including direct and indirect costs (Geigle,

2009).

Direct costs. Direct costs are expenses that are associated with a specific loss exposure

or occurrence and may include medical service costs, regulatory penalties, lost income from time

away from work, and increased worker's compensation premiums (Peate & Lunda, 2002).

Medical costs can be considered the major factor in direct costs associated with WMSDs, with

back injuries being some of the most costly ailments. Back injuries suffered in the workplace

can be some of the most costly injuries for a company to incur. Early intervention is increasingly

important when dealing with WMSDs because they are normally treatable and less costly to

rectify in the short term, but can become quite expensive and inoperable in the long term.

Approximately 5.4 million Americans cope with back injuries annually, costing $16 billion for

treatment, which accounts for .thirty to forty percent of all workers compensation claims

30

(Kearney, 2008). Back injuries are a dreaded and often chronic problem substantiated by the

California Department of Industrial Relation's assertion that one serious back injury claim may

incur or even surpass a cost of$85,000 ("Easy ergonomics," 1999). The injury claim may

involve surgical repair of several ruptured disks requiring fusion, and include rehabilitation,

therapy, lost wages, and disability pay (Feletto & Graze, 1997). Recovery from back injuries is a

slow process, and even after returning to work, many employees are placed in a restricted duty

status or transferred to another task to prevent reoccurrence. The exact cost of occupational

musculoskeletal disorders is not known, although estimates vary depending on the methodology

used in the data collection and measurement process. Work-related musculoskeletal disorders

are however, the most predominant health problems in America, affecting over 40 million people

aged 45 years and older and are projected to affect more than 60 million persons, or twenty two

percent of the population by the year 2030 (Lubeck, 2003).

Indirect costs. Indirect costs are associated with the loss of function in a worker's

normal routine, which may include work disability, sick leave or reduced productivity at the

worksite (Lubeck, 2003). A reduction in productivity may be related to a reduction in working

hours or a requirement to change the nature of the job task to reduce discomfort and improve

physical well-being. Indirect cost is a relatively misunderstood area which could include paid

work, education costs, parental care, or maintenance of a residence. Various studies have

indicated the contributory effect of employment on musculoskeletal disorders. Based on certain

conditions, the indirect costs of musculoskeletal disorders may equate to, or even surpass, the

direct costs. Precisely allocating the indirect costs of care due to lost income, or lost time spent

for education or completion of household chores, becomes somewhat difficult to determine.

31

There are several approaches to enumerating indirect costs, with the majority of emphasis

being placed on the human capital and the willingness to pay approach (Lubeck, 2003). The

human capital approach places a numerical figure on the hours of work lost; which is based on

the hourly salary issued for the job or task. The human capital approach may be based on either

personal or societal data. Personal data is used to evaluate the financial burden of lost

production time in comparison to the documented income of individuals who are diagnosed with

musculoskeletal disorders. The value may incorporate gross salary, costs incurred due to sick

leave, and bills for social security. Societal costs infer that a day of lost productivity will equate

to the same cost as the mean daily salary for the employee population as a whole. This approach

takes into account a varied field of labor costs for full time employees. The human capital

approach undervalues the work loss or disability days of elderly and female employees, which

tend to be the workers who are most susceptible for musculoskeletal disorders. Additionally,

there is no favorable method for placing a concise cost on non-workplace functions such as

household duties, providing parental support, educational work or community involvement.

These functions become underestimated using the human capital approach, and therefore, are

misrepresented to be the lowest cost of the whole burden of musculoskeletal disorders (Lubeck,

2003).

The willingness to pay approach conversely attempts to quantify what workers are apt to

assume financially for a modification resulting in better health status, such as a reduction in the

likelihood of death. This approach enables workers to assess an actual valuation of life and

death, and may be figured from society's viewpoint. The willingness to pay approach, however,

is cumbersome to carry out, and the process for acquiring the figures is very difficult to

32

comprehend because a worker must assign a value to increased survival, in terms of earnings, or

in terms of medical costs averted (Lubeck, 2003). The precise allocation of indirect costs then,

no matter how calculated, is often misunderstood and difficult to determine.

Indirect costs can be viewed not only as a computation of worker production losses,

which include salary loss and household activities loss, but would also incorporate employer

production loss, due to the interruption of the production line and the temporary or permanent

replacement of workers. This includes recruiting and training of new employees for injured

workers. In addition, administrative costs should be included in the total, including

administrative functions associated with a workers compensation program. A compilation of

indirect costs that are often overlooked include repairing damaged property, accident

investigation and implementation of corrective action, scheduling delays, administrative expense,

low employee morale and increased absenteeism, poor customer and community relations, long

term physical restrictions (light duty) of employee work activities, increased insurance premium

costs, and total cost of the time lost by the injured employee beyond the actual time away from

the job (Leigh, Markowitz, Fahs, Shin & Lanrigan, 1997). Indirect costs can be extremely

difficult to quantify, as they are not precisely attributable to the loss exposure or incident, and

very often persist over an extended period of time. The comprehension of the consequences of

loss exposure resulting from inadequate ergonomic situations is critical because loss is generally

larger than what initial expenditures appear to be, as evidenced by the Bureau of Labor Statistics

estimates that there were 1,238,490 musculoskeletal injuries in 2009 that accounted for workers

missing time away from work to recuperate ("Nonfatal occupational injuries," 2010).

33

Manual Material Handling Issues

Manual material handling (MMH) involves lifting, lowering, holding, restraining,

pulling, pushing, moving, carrying, and related activities which directly correlate with the

majority oftasks involved in the workplace setting (Stellman, 1998). The more precise

definition of manual handling, according to the U.S. Department of Labor, is the act of seizing,

holding, grasping, turning, or otherwise working with the hands, such as to rotate a switch or to

engage auto gears. Manual handling of packages may lead to the waste oftime and energy

resources, along with increasing the possibility for injuries from worker exposure to physical

conditions that include risk factors of force, awkward postures, and repetitive motions. To avoid

these problems, organizations can directly benefit from improving the fit between the demands

of work tasks and the capabilities of workers. A worker's ability to perform various tasks may

vary because of differences in age, physical condition, strength, gender, stature, and other

factors. Changing the work surroundings through redesigning the fit, generally, can benefit the

workplace by ("Ergonomic guidelines," 2007):

• Reducing or preventing injuries.

Reducing an employee's efforts by diminishing forces in lifting, handling, pushing, and

pulling materials.

Reducing ergonomic risk factors for musculoskeletal disorders such as awkward postures

from overextending the reach envelope.

Increasing productivity, product and service quality, and worker morale.

34

Lowering costs by reducing or eliminating items like production stoppage, error rates or

rejects, use of medical services because of musculoskeletal disorders, worker

compensation claims, excessive worker turnover, absenteeism, and retraining.

Manual material handling tasks often present workers with situations that involve many physical

risk factors. If these certain job tasks are performed with repetition or for extended periods of

time, they can lead to fatigue and injury. The major risk factors, or conditions, associated with

the development of injuries in manual material handling tasks include ("Ergonomic guidelines,"

2007):

e Awkward postures from bending or twisting.

• Repetitive motions due to frequent reaching, lifting, or carrying of materials.

• Forceful exertions from carrying or lifting of heavy loads.

• Pressure points relating to grasping or contact from various loads, or resulting from

leaning against parts or work surfaces that are hard or have projecting edges.

• Static postures from maintaining fixed positions for an extended time period.

The repetitious exposure to these risk factors initially may lead to tiredness and discomfort for

the worker, which over time, could cause injury to the back, shoulders, hands, wrists, or other

parts of the body may occur. Injuries may include damage to muscles, tendons, ligaments,

nerves, and blood vessels, commonly known as work-related musculoskeletal disorders

(WMSDs ). Subsequently, the compounding influence of negative environmental conditions,

such as extreme heat, cold, noise, and poor lighting, may increase a workers' chance of

developing additional varieties of medical or physiological oriented issues.

35

Worksite Analysis

Worksite or job safety analyses can be completed to measure a worker's exposure to

work-related risk factors for musculoskeletal disorders. Exposure potential to the major risk

factors of force, posture and repetition can then be compared to relevant human capabilities to

calculate injury probabilities (Putz-Anderson, 1988). A job safety analysis is a method for

grasping a keen understanding of the process involved in performing a job function. The

analysis simplifies a job function into steps and identifies the corresponding potential hazards.

The analysis then enables the user to identify methods of elimination or control to reduce hazard

exposure. A worksite analysis is a combination of systematic actions to provide the information

needed to recognize and understand the hazards and potential hazards of a workplace ("Safety

and health," 2011). These actions are as follows:

• Comprehensive hazard identification.

• Comprehensive hazard surveys.

• Hazard analysis of changes in the workplace.

• Routine hazard analysis or job safety analysis (JSA).

• Regular site safety and health inspections.

• Employee reports of hazards.

• Accident /incident investigations.

• Injury and illness trend analysis.

A comprehensive hazard survey is the most basic of all the items used to create the list of current

hazards and potential hazards at a workplace. Following the establishment of an initial reference

point, inclusive surveys need to be completed on a regular basis to correlate new information

36

about hazards or the introduction of new hazards into the working environment. In each

occurrence in which there is a modification in the buildings, machines, procedures, or materials

in the workplace, there should be an analysis for potential hazards. A continual improvement

checking mechanism for adherence to quality standards is the audit review of comprehensive

hazard surveys. The analysis should be undertaken with commitment and patience to ensure

proper recognition of exposure to various hazards that may act independently or symbiotically.

Criteria in the basis for evaluation ofhazards may include ("Safety and health," 2011):

• Severity- Is an exposure likely to be serious in nature?

• Frequency /Probability - How likely? Could this happen on a regular interval or once in

several years?

• Type of injury or illness - What type of incident would happen to a worker?

• Extent of use- Is different equipment in constant use or is only one machine in

occasional use?

• Maintenance and repair - Is planned maintenance performed on a regular basis or

completed only when break downs occur?

• Training - Is training required to run the equipment or is a new worker with little training

likely to be assigned to the machine. If so, is extensive formal training required?

• Government regulations - Is there an OSHA standard that governs operation?

It is important to identify potential exposures to risk factors in hazardous areas, and a worksite

analysis is useful in the determination ofbeneficial work designs (Putz-Anderson, 1988).

37

Ergonomic Analysis Tools

In 2008, Silvia Pascual and Syed Naqvi, from the Occupational Health Clinics for

Ontario Workers, distributed web-based surveys to the Joint Health and Safety Committees

(JHSCs), to Canadian certified ergonomists, and to health and safety certification trainers in

Canada in an attempt to identify which ergonomic analysis tools were utilized the most in

industry and also to help JHSCs obtain the necessary training required to reduce WMSDs

(Pascual & Nagvi, 2008). The collected data indicated that the majority of certified ergonomists

used the Snook tables, the National Institute of Occupational Safety and Health (NIOSH) revised

lifting equation, the rapid upper limb assessment (RULA), and the rapid entire body assessment

(REBA). The most frequently used methods by JHSCs to initially identify the potential presence

of ergonomic risk, were injury reports and worker complaints. Ergonomic analysis tools often

include various methods and assessments that may be utilized to fulfill the goals of improving

worker health and safety and also organizational productivity in the working environment. The

ergonomic analysis tools utilized in the completion of this study are briefly outlined below.

Rapid upper limb assessment. Rapid Upper Limb Assessment (RULA), see Appendix

A, is an assessment tool designed for use in ergonomics analyses of working environments in

which work-related musculoskeletal disorders are discovered. This method utilizes no special

equipment in providing a simple assessment of the postures of the neck, trunk and upper limbs

along with muscle function and the external loads experienced by the body. A coding system is

used to generate an action list which indicates the level of intervention required to reduce the

risks of injury due to physical loading on the operator (McAtamney & Corlett, 1993). RULA is

intended to be used as part of a broader ergonomic study and the assessment process uses a

38

simple numerical number system that ranks posture, force, and type of movement. Upon

completion of the assessment, the job task that was analyzed will have a one to seven ranking,

with seven being the most severe and requiring immediate attention for change (Stanton, Hedge,

Brookhus, Salas & Hendrick, 2004).

Rapid entire body assessment. Rapid Entire Body Assessment (REBA), see Appendix

B, is a method to assess posture for risk of work related musculoskeletal disorders (WMSDs ).

REBA is a postural analysis tool which is focused on sensitivity to the kind of unpredictable

work related postures found in many service industries (Hignett & McAtamney, 2000). It is

exclusive to analyzing the hazard of a single job function by analyzing the load, posture,

movement distance, movement activity, and height. The REBA method was designed by Dr.

Sue Hignett and Dr. Lynn McAtamney, ergonomists from University of Nottingham in England,

and is essentially a postural targeting method for estimating the risks of work-related entire body

disorders. The REBA assessment provides a fast and systematic assessment of the complete

body postural risks that an individual worker would face. The analysis can be conducted before

and after a redesign modification to illustrate if the redesign has worked to lower the risk of

injury (Hignett & McAtamney, 2000). The REBA assessment, as with RULA, will be scored

base on the postures and demands required by the job activities. The developers of REBA

suggest that the user should take pictures and/or a video of the task. To perform a thorough

REBA analysis, the user needs to choose which postures and segments of the work cycle need to

be assessed. This can be accomplished by viewing the postures used over a complete job

function cycle and, ideally, to view the job function being performed a number of times (Stanton

et al., 2004).

39

NIOSH revised lifting equation. The National Institute of Occupational Safety and

Health (NIOSH) Revised Lifting Equation (see Appendix C) is used to determine manual lifting

and lowering weight limits. Relatively safe weight limits for manual lifting jobs can be

recognized through the use of the revised NIOSH lifting guide. The two primary aspects of the

guide (i.e., the lifting index and the recommended weight limit) can assist to determine if a task

or job function is inherently safe (Peate & Lunda, 2002). The recommended weight limit (RWL)

is determined for specific task conditions as the weight of the load that 75 percent of female and

99 percent of male workers can lift safely (Waters, Putz-Anderson & Garg, 1994). The RWL

reflects the likelihood of a hazard or physical disorder occurring related to the lifting task and is

computed using data from the load constant, horizontal, vertical, distance, asymmetry, frequency

and coupling multipliers. The lifting index can be analyzed once the RWL is calculated. The

lifting index (LI) provides an estimate of the physical stress accompanying certain job tasks

where a value at or below one is acceptable and above one is an indication that one or more of

the measured lifting-related variables should be studied and consequently reduced (Waters et al.,

1999).

Liberty Mutual MMH tables. Initially, in 1978, Snook, and later in 1991, Snook and

Ciriello, published data derived from an encompassing psychophysical research study for Liberty

Mutual Insurance, which started in 1967. The data were compiled into a series of tables which

delineated maximum acceptable weights and forces for various gender, and population

percentiles in relation to basic manual material handling tasks. This data has been referred to as

the Snook tables in the past, and are now known as the Liberty Mutual Manual Material

Handling (MMH) tables (see Appendix D). Rather than utilizing an integrated Analysis

40

Package, separate packages for Push/Pull, Carry and Lift/Lower are presented in a standard

format. The design goal tables are a diminished version of the Snook and Ciriello tables. The

focus is on design goals based on 75% acceptable for women (Liberty Mutual manual, 2011).

Ergonomic worksite assessment. There are a myriad of tools that can help in the

identification of ergonomic risk factors and in the facilitation of an ergonomic worksite

assessment. Some of the more commonly used methods include ("Ergonomics program," 2003):

.. Employee interview/questionnaire/discomfort survey: The interview, questionnaire and

discomfort survey are utilized to obtain the employee's opinion about risk factors present

in the workplace. A personal interview or a written questionnaire is the most often used

method. Anonymous written questionnaires are typically less intrusive to an employee

and therefore, have a higher completion rate.

.. Ergonomic risk factor checklist: An ergonomic risk factor checklist is utilized by a

researcher to ascertain potential risk factors that may be commonly found in a specific

job. Checklists provide a relatively efficient and easy method to identify the most

obvious risk factors. This method should be used along with at least one other analysis

method for the most inclusive results.

.. Videotaping: An individual videotapes the normal job function from different angles for

a length of time (most often ten to twenty minutes or through at least three complete work

cycles) and can then view the tape later. This method allows for slow motion viewing

and gives observers the ability to review certain sections many times if necessary. The

video recorder can also record the body movements of tasks being performed by workers.

This instrument can be set up to capture various angles, time periods, and actions not

41

normally observed, and then can be analyzed for posture, repetition, force and duration

risk factors by the researcher.

• Narrative review/observation sampling: An individual visually examines the job task for

a length of time (generally thirty to forty minutes or through five or ten complete work

cycles) and writes down a detailed description of observations, specifically any possible

hazards that may increase the potential for loss.

• Review of available records: Ergonomics personnel may review available work records,

such as the OSHA log 300, for signs of potential work-related musculoskeletal disorders.

Specifically, any injuries or illnesses related to parts of the musculoskeletal system

should be noted and reviewed.

The utilization of as many different tools as possible will ensure a more thorough analysis that,

in tum, will lead to more complete ergonomic solutions ("Fitting the job," 2005). A summary of

recorded data can then be utilized to confirm the risk factors and determine possible causes.

Analysis and identification of the underlying causes of the ergonomic risk factors will aid in the

procurement of solutions. If the variations of musculoskeletal disorders that are present at a

particular job task do not correlate with the risk factors identified, then further investigation is

generally needed to ascertain the cause for these MSDs.

Risk Control Methods Hierarchy

Controls can be defined as procedures, method changes, or processes that correct existing

health problems and minimize the risk of health hazards in the workplace (Friend & Kohn,

2007). There are certain approaches to minimizing or controlling risk factors that are associated

with job tasks in the manufacturing industry. These approaches may be defined via a three-stage

42

hierarchy of controls and are commonly accepted as a major strategy for controlling workplace

hazards. These three stages include (Cohen, Gjessing, Bernard & McGlothlin, 1997):

• Reducing or eliminating potentially hazardous conditions using engineering controls.

• Instituting changes in work practices and management policies known as administrative

controls.

• Using personal protective equipment.

Through the use of engineering controls, the process designer is attempting to eliminate or

reduce the physical hazards and thus present the employee with fewer ergonomic-based risk

factors. Administrative controls take the opposite path compared to engineering controls in that

they are more procedural based and try to remove the worker from the process or limit the

exposure time received by a worker from each task. The last line of defense is personal

protective equipment, which is generally designed to reduce the hazards that employees are

exposed to by the utilization of protective items worn on the worker's body (Chengular, Rodgers,

& Bernard, 2004).

Quality ergonomic designs are not by chance alone and are created for the majority of a

population, fitting roughly 95 percent of all male workers in the workplace. Anthropometry is a

term used to describe the measurement of physical human characteristics in order to determine

allowable space and equipment size and shape used for the workplace. Items that are reviewed

include agility and mobility, age, gender, body size, strength, and disabilities. Designing the

work environment to fit the entire range ofbody sizes of workers is rarely performed (Chengular,

Rodgers, & Bernard, 2004). Therefore, it is necessary to apply anthropometric data to

accommodate the majority in order to design for 90 to 95 percent of the worker's dimensions.

43

Accommodating 95 percent of body sizes means that the process design eliminates the smallest

2.5 percent and the largest 2.5 percent from consideration. Designing for the mean of a

population is a serious error and should be avoided whenever possible because a basic rule of

ergonomics is that there is no such thing as the "average" person. However, it may be necessary

to design for the tallest individuals (95th percentile) to determine leg room under a table or for

the shortest individuals (5th percentile) for reach capability ("A guide to ergonomics", 2009).

Ergonomic analysts rely on many different tools to help them create or correct a working

environment. These tools are part of the three-stage hierarchy including engineering controls,

administrative controls, and personal protective equipment. These controls can be used

individually or combined to obtain the desired ergonomic control.

Engineering controls. This physical environment approach should be the primary

means of eliminating or reducing the occurrence of work -related musculoskeletal disorders and

may include redesigning the job, the workplace, or equipment (Tayyari & Smith, 1997). The

ergonomic principles that should be considered when creating or altering the work environment,

as recommended by Tayyari and Smith (1997) include:

• Discontinuing repetitious job functions that incorporate the use of abnormal postures or

excess force.

e Developing job functions which include additional tasks that allow varied motions and

activities. This will enable a worker to assume different body alignments throughout the

working day and prevent the repetition of the same movements over an extended time

frame.

44

• Promoting a cycle length of greater than thirty seconds, with preference of 1.5 minutes

for tasks requiring a swift pace.

• Discouraging the occurrence of stationary posture for extended time periods, even in a

neutral position.

• Employing the whole hand when grasping an object and avoiding the use of pinch grip

postures.

• Balancing an object's weight by holding it close to its center of gravity.

• Utilizing tools with projecting collars or custom-fit grips which direct a workers exertion

in the direction of the tool use.

• Reducing or eliminating pushing, pulling, grasping, or lifting tasks which involve the use

of excessive force.

• Discouraging workers from applying direct pressure against a hard surface or work tool

in order minimize or prevent contact forces.

• Allowing numerous breaks in any type of tasks that include repetitious movements over

extended lengths of time. This will aid in the recovery of stressed muscles.

• Preventing workers from performing job functions with extreme vibrations or

temperatures.

• Preventing work in an environment that causes deficient posture or extreme force because

it will increase the potential for injury.

• A voiding repetitious and vigorous job functions by automating the task if possible for a

company.

45

Cohen et al. (1997) recommend the following engineering control strategies to reduce ergonomic

risk factors:

• Changing the way materials, parts, and products can be transported.

• Changing the process or product to reduce worker exposures to risk factors.

• Modifying containers and parts presentation.

• Changing workstation layout.

• Changing the way parts, tools, and materials are to be manipulated.

• Changing tool designs.

• Changes in materials and fasteners.

• Changing assembly access and sequence.

The benefit of using engineering controls first is to design the risk exposure potential out of the

process, which will reduce the chance of injury or illness. Engineering solutions can be

determined once tools such as the NIOSH Lifting Equation have identified the most prevalent

risk factors. Tayyari and Smith (1997) believe there are a multitude of engineering designs that

could be implemented on working environments, tools, and work methods to alleviate excess

force, repetitious movement, and unnatural postures. Based on an engineering control method's

potential for eliminating human error, it is quite evident that these controls are the recommended

choice to eliminate or reduce hazards in the workplace. Additional engineering control strategies

that Cohen, et al., (1997) recommend to reduce ergonomic risk factors include:

• Altering the system of transportation for materials, parts, and products by installing

mechanical assist devices to reduce manual material handling and carrying or by the use

of handles or slotted hand holes in packages.

46

• Altering the process or product to reduce worker exposures to risk factors that may

include maintaining the fit of plastic molds to reduce the requirement for manual removal

of flashing, or using easily connectable electrical terminals to reduce manual forces.

• Altering containers and parts delivery to the assembly process, such as height adjustable

material bins.

• Altering worksite configuration, which might include using height adjustable

workbenches or placement of tools and materials within short reaching distances.

• Altering the method that parts, tools, and materials can be handled by using fixtures to

hold the products which minimizes the need for awkward upper extremity alignments.

• Altering assembly access and sequence.

These methods are all reconfiguring the process to protect the worker from potential ergonomic-

based hazard exposures. These controls are generally the most beneficial long-term approach to

eliminating or reducing the risk factors associated with WMSDs (Chengular et al., 2004).

Administrative controls. Administrative controls are management influenced work

practices and policies which are created to reduce or prevent exposures to ergonomic risk factors.

Engineering controls are the preferred method for eliminating and reducing ergonomic risk

factors, but when engineering controls are not possible or not immediately