Spinal Biomechanics Ergonomics

7/28/2019 Spinal Biomechanics Ergonomics

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Workplace Ergonomics
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Presentation Objectives

participants wil l be able to...

Understand basic concepts of ergonomics

Identify common musculoskeletal injury risks

Learn strategies to decrease MSD injury risks

Address questions on ergonomics and back

safety


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ErgonomicsStudy of Work

The science of fitting the job to theworker

ergo = work

nomics = study of


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What are the physical demands of yourjob


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Job Risk Factors

Working in awkward postures / positions

Prolonged sitting and standing

Bending, reaching, stretching Driving for extended periods of time

Heavy lifting

Awkward lifting

Lifting in combination with twisting

Pushing, pulling, carrying

Accidents, slips, trips, falls

Vibration


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Goals of Ergonomics ProgramReduce work-relatedmusculoskeletal disordersdeveloped byworkers when their jobs involve...

Awkward postures Static positions

Reaching

Bending & Lifting

Force

RepetitionContact stress

Vibration

Repetition

U.S. Department of Labor Occupational Safety & Health Administration


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What are MusculoSkeletal Disorders?

MSDs are injuries and illnesses that

affect muscles, nerves, tendons,

ligaments, joints or spinal discs.

U.S. Department of Labor Occupational Safety & Health Administration


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Common Body Parts Prone ToWorkplace MSDs

Back - Lower Neck and Upper Back

Upper Extremities - Arms and Hands

Lower Extremities - Legs and Feet


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Examples of MSDs

Carpal tunnel

Rotator cuff syndrome

Lateral epicondylitis

- tennis elbow

Low back pain


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Musculoskeletal Disorders:

Signs and Symptomsin general

Decreased ROM

Decreased grip and/or

pinch strength

Swelling

Fatigue

Loss of function

Numbness

Burning sensation

Tingling

Pain

Cramping

Stiffness

French & Zecha, 2005


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Musculoskeletal Disorders: How & Why?

Related to intensity of work

Have biomechanical and physiological factors Can occur after weeks, months, years on job

Can take weeks, months, years to resolve

Have occupational and non occupational

causes



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Musculoskeletal Disorders: How & Why?

listening to our body

Disruption in balance between breakdown and

recovery 1st sx.fatigue (of body part)

2nd sxache

3rd sxpain

Leading to loss of function



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Adaptation vs. Injury

the fork in the road

Adapt

Soft tissue remodels

More strength

More stability

More endurance

Discomfort

decreases

InjurySoft tissue breaks down

Less strength

Less stabilityLess tolerance for use

Discomfort increases



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QUESTIONS?


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Part Two

Some Ergonomic

Risk Factor Concerns


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Introducing our 2nd focus area for

today

Back care

Posture Contact stress

Repetition


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Posture check: reaching & bending

its all connected and its all about physics

Load & leverage

10# vs. 70# low back

15# vs. 45# head &neck

Think about posture Forward head

Sitting

Reaching


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Its all Physicsleverage


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Posture

Think of posture in terms of joint position

Static and awkward postures lead to: Decreased movement

Decreased circulation

Increased stress and fatigue


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Posture check

Increased stress, decreased circulation

Higher risk Lower risk


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Posture check

ask yourself

Do you use a headset rather than cradling thetelephone between your head and shoulder?


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Posture check

ask yourselfAre you sitting against the back of your chairwhile you work?

Is your head/neck upright and centered over

your shoulders when you look at the screen ordocuments?

Are your shoulders relaxed when keying andusing the mouse?

Are your arms close by your sides when youuse the keyboard or pointer?


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Posture checkask yourself

Are your elbows relaxed (100 degree angle)when using the keyboard or mouse?

Are your wrists in a neutral position (alignedwith your forearm) when keying or using thepointer?

Are you avoiding awkward postures such asan extended finger or thumb when keying orusing the mouse?


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Equipment set-up example

risk identification

Elbow and shoulder away from body, reaching

increased strain on shoulder and wrist


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Elbow and shoulder more relaxed and closer to body

decreased strain on shoulder and wr ist


risk identification


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risk identification

Forward placement of document holders and monitor

prevents excessive turning and bending stress in neck,

upper back and torso

Posture:

keeping itstraight!


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A word on repeti tion

Key issue is recovery time

- the time required for tissue to restore nutrition, replace

cells, dissipate byproducts

- rest breaks

Some newer research demonstrates that repeti tion

is signif icantly less of a problem vs. posture


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A word on contact stress

At your workstation notice where your body comes

into contact with objects

Where are your:

Front & back of knees

Elbows

Wrists

Back

Behind

Calves, feet, ankles


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QUESTIONS?


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Part Three

Workstation equipment

use and set-up!


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Is my ergonomic potato chip really

ergonomic?

To be ergonomic a design

must

Fit the user

Be easy to use

Improve comfort

Improve performance

Improve health and safety

Not just bells and whistles!


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Computer workstation ergonomics

Chair

Monitor Keyboard

Mouse

Document holders

Lumbar pads/pillows Arm rests

Glare

Eye strainFootrests

Wrists pads

Keyboard trays

Laptops


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Chair Basics

Good lumbar (low back) support

Comfortable sitting for at least 2 hours

Chair has 5 point base

Adjustable arm rests (or none)

Seat pan is comfortable

Easily adjustable while sitting Appropriate height & depth of seat pan


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Monitor issues and glareprotect your eyes !

Eye-to-screen distance at least 18 inches Top of screen at eye level or slightly below

Dont stareblink frequently to lubricateeyes

Use blinds to control outside light Screen colors: dark letters on lightbackground (IBM blue)


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Work technique

ask yourself

Do you avoid leaning on the wrist rest while keying and

mousing?

Are you using a light touch to key?

Are you holding your mouse loosely with your hand and

fingers in a relaxed position?

Do you let go of the mouse when not using it?Do you take 20 second breaks after every 20 minutes

of keying?


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Work technique

ask yourselfDo you take eye breaks and look at a distance every

20 minutes?

Do you blink while you look at the screen?

Do you take stretch breaks throughout the day?

Have you set up your work to encourage alternating

sitting and standing throughout the day?

Have you optimized your settings on your computer

to make your work easier? (i.e. flicker rate, mouse

speed, font size)

Do you know how to adjust your keyboard tray andchair?


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Laptops

a few words

Harder on eyes and neck

Smaller screens

Lower quality displays

Lower viewing angle

Harder on wrists on arms

Narrow keyboard

Awkward posturesHarder on back

Carrying can strain back

Risk Reduction Measures External keyboards

Docking stations

Practice good posture on road

Risk Factors


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Watch those deadlines!

tension and stress -ask yourself


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Some final words

Lets think about it


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Back Safety & Ergonomics

isnt just a work thing!The big picture


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Ergonomics isnt just a work thing!

think physics & leverage working around home

Washing dishes, pots & pans

Carrying and loading groceries

Picking up and carrying kids

Walking the dog

Yard work

Raking, shoveling, sweeping

Lawn mowing, snow removal

Wheel barrels


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think of driving your car Elbow resting on door, center console

Wrist over steering wheel

Buttock and back pain

Posture

Nerve and tissue compression

Position of legs while driving

Muscle strain: hamstring tightness

Decreased circulation

Upper neck/back tension and pain

Muscle strain:upper trapezius

Stress reactions, trigger points

Eye strain

Glare

Dehydration


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think of sleeping in your bed

Neck posture

Shoulder and arm posture

Wrist posture

Knee and hip posture

Back posture

For long periods of time: static and awkward positions,

decreased circulation, increased compression!


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Ergonomics

there is no magic solutionwe are all unique in certain ways

Age

Gender

AnthropometricsBody Size & Shape

Equipment accommodates 5th% female to

95th% male

Skill Level

General Health and Condition


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QUESTIONS?


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Back InjuryFrom an Ergonomic View


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Common Back Disorders

General joint stiffness

Acute strains and sprains

Degenerative disk disease

Bulging disc

Herniated disc

Osteoarthritis


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Anatomy Review

the spine

Bones

Joints

Discs

Muscles and ligaments

Nerves


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Anatomy Review

the curves of the spine


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Poor Body Mechanics

Stressful Living & Working

Loss of Flexibility

Loss of Strength

Leading Causes of Back Problems


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Another cause of back problemsaccidents

It is also possible to injure

your back due to accidents.


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How do we take care of our back?

Body Mechanics

Proper Lifting Techniques

Exercise

Stretching

Improved postures


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Its not how much you lift or move, but the way you do it!

1) Push vs. Pull

2) Keep Work Within Strike Zone3) Keep Load Close To Body

4) Use Abdominal Bracing

5) Pivot with Feet - Avoid Twisting

6) Team Work vs. Mule Work

Body Mechanics

General Rules:


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Power Position:

Wide base of support

Feet shoulder width apart Back straight

Head and shoulders up

Bend at hips and knees - NOT BACK!

Keep load close to body Tighten stomach muscles

Use leg, hip and buttock muscles

Breathe out with lift

Proper Lifting Technique


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QUESTIONS?

Spinal Biomechanics Ergonomics

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