1 Intro to yjhh

8/10/2019 1 Intro to yjhh

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Preventing Musculoskeletal

Illnesses through Ergonomics


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Session Objectives

Define ergonomics and provide brief history

SMU Statistics

Discuss purpose, scope and goal of ergonomics Design and Task Factors that effect ergonomics

Physical effects of risk factors

Present application strategies with emphasis on job

design

Examples

ERGONOMICS


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What Is Ergonomics?

Ergonomics focuses on fitting jobs and tasks to theworker that must perform them.

The basic definition is the study of work in relation to thephysiological and psychological capabilities and limitations

of people.Ergonomics utilizes the principles of many differentdisciplines, engineering, physics, psychology, humanphysiology, and business management.

Ergonomists are able to reach their goals throughengineering and workplace designs.

Ergonomics from the Greek words:

Ergo = work

Nomos = laws

ERGONOMICS


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Other Terms

Engineering psychology

Human factors

Human engineering

Biomechanics

Work physiology Engineering anthropometry

ERGONOMICS


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ERGONOMICS

History of ErgonomicsStover H. Snook Ph.D., Harvard School of Public Health

PHYSIOLOGICAL ROOTRamazzini (1633-1714)

Alice Hamilton (1869-1970)

Health of Munnition Workers Committee (1915)--UK

Industrial Fatigue Research Board (1918)--UK

Industrial Health Research Board (1928)--UK

Harvard Fatigue Laboratory (1927-1946)

PSYCHOLOGICAL ROOTHawthorne Studies (1924-1927 NRC)

WWII weapons systems

Army gunnery studies (Tufts University)

Navy systems Research Lab (Harvard, Johns

Hopkins)

Air Corps flight program (Ohio State)

ENGINEERING ROOTFrederick W. Taylor (1856-1915)--time study

Frank and Lillian Gilbreth--motion study

WWII radar, computers, nuclear devices, high performance aircraft

Biomechanics--medical applications

ANTHROPOMETRIC ROOTWWI--Army surveys for clothing size

U.S.. Depts. of Agriculture and

Commerce (1939) Surveys of women

and children, and standards in clothing

sizes

WWII--Military surveys for clothing

and equipment

ERGONOMICS


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20 Claims

0.06

761 Claims

0.27

17 Cliams

0.05

422 Claims0.15

11 Claims

0.03

454 Claims0.16

10 Claims

0.03

187 Claims0.07

7 Claims0.02

207 Claims

0.07 21 Claims

0.06

946 Claims

0.34

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Accidentsper$1MMo

f

Payroll

MMH SLIPS/FALLS-SAME

LEVEL

STRUCK BY/AGAINST CTD SLIPS/FALLS-

ELEVATION

ALL OTHER

Top Five Accident Types

Southern Methodist Univ. Liberty Mutual Industry Average

(4/1/00 to 3/31/03)


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$73,570 Incurred Cost

$0.02

$2,647,073 Incurred Cost

$0.09


$0.04


$0.08


$0.01

727,487 Incurred Cost

$0.03


$0.02


$0.03

$45,747 Incurred Cost$0.01


$0.04


$0.01

$1,430,654 Incurred Cost$0.05

$0.00

$0.01

$0.02

$0.03

$0.04

$0.05

$0.06

$0.07

$0.08

$0.09

$0.10

DollarCostper$100ofP

ayroll

MMH SLIPS/FALLS-

SAME LEVEL

STRUCK

BY/AGAINST

CTD SLIPS/FALLS-

ELEVATION

ALL OTHER

Top Five Accident Types

Southern Methodist Univ. Liberty Mutual Industry Average

(4/1/00 to 3/31/03)


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Ergonomics

The overall goals of ergonomics are:Provide a safe and healthful work environment

engineered to the capabilities of the human

body

Decrease worker fatigue and discomfort throughthe elimination or minimization of excess effort

Increase efficiency and productivity

Improve production by providing designs that

reduce the potential for human error

Enhance customer service through improvedworker morale

Elevate job satisfaction

Reduce injuries/illnesses

Reduce Costs

Improved Work Methods

Increased Efficiency

Better Tools

Less Fatigue

Fewer Errors

Less Rework

Increased Productivity

ERGONOMICS


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Anthropometry

The average person fallacy

ERGONOMICS


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Individual Differences:Most Important Are Age and Gender

We get shorter as we age

We get weaker as we age

Women have less than 50% of the isometric strength asmen

Female heart rates are higher

Females recover faster from exertions

8% of males are color deficient Response time, vision, and hearing deteriorate with age

10% of population is left handed

ERGONOMICS


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Material

CharacteristicsTask/Workplace

Characteristics

Organizational

CharacteristicsEnvironmental

Characteristics

Task Demands

Worker Capacity

Personal

Characteristics

Physiological

Capacity

Psychological

Capacity

Biomechanical

Capacity

Quality

Performance

Fatigue

Discomfort

Injury

Primary factors

influencing task

demands to worker

capacity

(dempsey, 1998)

P.G. Dempsey, A Critical review of biomechanical, epidemiological, physiological andpsychophysical criteria for designing manual handling tasks, Ergonomics, 1998, Vol. 41. No1


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Ergonomics ProcessPre - Injury Prevention

Post - Injury Action and Return to Work

Management Leadership

Job Hazard Analysis

Education and Training

Hazard Reduction & Control

Job Placement Medical EvaluationsDisability Management Programs

Rehabilitation Services

Health Care Liaison Plan

Ergonomic Job Accommodations

Transitional Duty

Worker

Employee Participation

Targeting Primary Cost Drivers

ERGONOMICS


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The shoulder joint is perhaps one of the most mobile and mostcomplex of the joints in the human body. The importance of theshoulder joint becomes apparent when one considers the types ofactivities associated with the shoulder:

Pushing

Pulling

Lifting

Pressing

Holding

The shoulder joint is involved either as a prime mover or as a supportfor almost every activity that involves the arms. This is accomplishedby the inherent mobility of the shoulder. The shoulder is made up ofcomplex bones and muscles that interact to form the shoulder

girdle.

Shoulder/Neck/Back

ERGONOMICS


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The vertebrae are the bone components of the back, and collectively

Form the spine. The vertebrae are classified based on their location

In the spine, including:

Cervical

Thoracic

Lumbar

Sacrum

Coccygeal

Shoulder/Neck/Back

ERGONOMICS


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CTDs

Cumulative Trauma Disorders:

To start with, CTDs are disorders of the musculoskeletal

system. That means that they are related to the muscles,

nerves, tendons, ligaments, cartilage, and joints of the body. Typically, CTDs are not sudden injuries, but are rather

illnesses that develop gradually over time.

CTDs are commonly a resultant of repeated mechanical

stresses on the body.

CTDs can result in losses of mobility and strength of the body. CTDs are also commonly known as Work-Related

Musculoskeletal Disorders, which means that the persons

occupation played a role in development of the condition, or

made a preexisting condition worse.

ERGONOMICS


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Common CTD Symptoms

Loss of feeling, sluggish

or weak muscle or joint

Numbness Tingling

Soreness in evenings

or after extended

activity periods

ERGONOMICS


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Hand/Wrist/Arm

Common ergonomic risk factors to the hand/wrist/arm include:

Awkward Postures

Forceful Exertions

Repetitive Movements

Mechanical Stress

Vibration Temperature Extremes

Wrist Flexion Wrist Extension

Ulnar DeviationRadial Deviation

ERGONOMICS


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Hand/Wrist/Arm

The nerves that service the forearm and hand include the ulnar,

radial, and musculocutaneous nerves. The nerves that connect and

move the wrist and hand include the radial, ulnar, and median nerves.

The ulnar nerve and arteries travel along the forearm and outside the

carpal tunnel. The median nerve passes through the carpal tunnel.

ERGONOMICS


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Hand/Wrist/Arm

The hand/arm/wrist are subjected to several different stresses.

Therefore, there are quite a few CTDs associated with the

hand/arm/wrist. These include:

Tendonitis Tenosynovitis

De Quervains Disease

Trigger Finger

Carpal Tunnel Syndrome (CTS)

Ganglion Cysts

Epicondylitis

ERGONOMICS


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Tendonitis

Inflammation of tendons.

Tendons are the connective

tissue that links muscles tobones, and allows for translation

of muscular contraction into

skeletal movement. Undue

physical force and repetitive

motions can cause inflammation

of the tendons, resulting in

tendonitis.

Hand/Wrist/Arm

ERGONOMICS


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Tenosynovitis (De Quervains Disease, Trigger Finger)

Inflammation of a tendon sheath. Tendon sheath provide

lubricated pathways in the human body so tendons can move

freely along their designed axis of movement. The sheath

minimizes friction which helps to protect the tendon. Repetitivemotion can cause inflammation of these sheaths.

Hand/Wrist/Arm

ERGONOMICS


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CarpalTunnelSyndrome- CTSCompression of the median nerve within

the carpal tunnel. The carpal tunnel is a

location where several tendons pass

through the wrist, connecting to the

fingers of the hand. The median nervealso passes through the carpal tunnel.

When pressure in the carpal tunnel is

increased (possibly due to ergonomic

risk factors) that pressure is translated to

the median nerve, causing inflammation

to the nerve. This can result in symptoms

of numbness, tingling or burning in the

area of the hand connected by the

median nerve (first 3 fingers)

Hand/Wrist/Arm

ERGONOMICS


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Ganglion Cysts

A benign cystic tumor connected to a

joint membrane or a tendon sheath.

These cysts consist of a thin fibrous

capsule enclosing a clear mucinous

fluid. Most commonly seen on the

backside of the wrist, ganglionic

cysts may also form at the shoulder,

elbow, or knees.

Hand/Wrist/Arm

ERGONOMICS


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EpicondylitisInflammation of the tendons that anchor

the muscles of the forearm to the elbow.

These muscles and tendons also connect

to both the fingers and the hand.Repetitive use of these muscles and

tendons, in maneuvers such as grasping,

twisting, and gripping, can cause

inflammation, and thus epicondylitis.

Other terms by which epicondylitis is

also known are:

Lateral EpicondylitisTennis Elbow

Medial EpicondylitisGolfers Elbow

Hand/Wrist/Arm

ERGONOMICS


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Repetition= Performing the same motionor group of motions excessively.

Examples of Repetition

Repeating the same motion every few

seconds or repeating a cycle of motions

involving the same body parts more

than twice per minute for more than 2

consecutive hours in a row

Using a tool or an input device, such asa keyboard in a steady manner for

more than 4 hours total in a work day

Excessive

repetition ofmovements can

irritate tendons

and increase

pressure onnerves


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Force= A strong physical exertion

Exertion = the tension

produced by muscles

and transmitted through

tendons

Excessive muscle tension

can contract muscles totheir maximum capability

which can lead to fatigue

and possible damage to the

muscles and other tissues.

Before: Threeemployees

climb on

garbage bin to

dump cart full

of waste. They

risk back strain

and lacerationswhile tipping

cart over to

empty it.

Ergonomic

Improvement:One worker

easily dumps

waste in half

the time.


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Applications of Ergonomics

Workplace design

Product design

System design

ERGONOMICS


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Early Symptom Reporting

Gradual BreakIn

Job Rotation Breaks/Stretching

Training on Job Tasks

Case Management of Injuries

Administrative ControlsERGONOMICS


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Work Environment/Organization

Performance/Time Pressures

Role within ProcessClarity/Ambiguity

Recent Changes in Process/Equipment Advancement Opportunities

Perceived Workload

Job Satisfaction Safety Culture

Employee Relationship w/Management

Psychosocial FactorsERGONOMICS


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ERGONOMICS

Neutral Posture for Computer Use

Adjust the seat height

so upper arms hang

vertically, elbows bent

about 90 degrees,

shoulders relaxed and

wrists fairly straight

Position the monitor about anarms length away directly in

front of you. The top of the

screen no higher than eye

level (Unless the user wears

bi-focal glasses)

Use a documentholder close to the

monitor rather than

laying papers flat

Mouse should be next to

keyboard both at a height

equivalent to the users seatedelbow height

Knees comfortably bent with

feet resting on the floor. If the

chair is raised so the keyboard

height equals elbow height, use

a footrest.

Adjust

the back

rest to

providefirm

support

to the

small of

the back


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Task Breaks and Stretches

Task breaks are VERYeffective in reducing the risk of

CTD

Short recovery periods are beneficial every 30

minutes

Use specific movements tooptimize recovery

Exhale!

Take a deep

breath!

ERGONOMICS


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Lean back gently with

hands supporting lower

back. Hold for 5

counts. Dont over

arch.

Gently roll shouldersbackwards 5 times and

then forward 5 times.

Move arms overhead

in a climbing motion 10

times.

Shoulder/Back StretchesERGONOMICS


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FURNITURE AND WORKSTATION ERRORS

Ergonomic features

that seem to add

value but dont

Keyboard height sidesurface is too shallow

for a computer.

Overhead file cabinet

blocks monitorforcing an awkward

setup.

ERGONOMICS


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FURNITURE AND WORKSTATION ERRORS

Armrests that get in

the way.

Too large, too far forward

Keep worker from sittingclose to workstation.

Forces long reach OR

Workers sit at edge of chair

Here, this worker boughthis own back pad to

compensate for the

problem.

ERGONOMICS


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Examples

BEFORE AFTER

ERGONOMICS


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ExamplesERGONOMICS


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Examples

Documents

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