workplace ergonomics

Workplace Ergonomics

Dr. Neo Chee BengOrthopaedic and Traumatalogy Surgeon

Kluang Utama Specialist Hospital

Ergonomic and Backache


Aim

To provide the user with the knowledge and skills to:

•Ergonomically setup their workstation• •Perform correct pause stretch exercises

•Questions and answers to win a prizes

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What is ergonomics?

Ergonomics

ERGO + NOMICS = ERGONOMICS“work” + “rules or laws” = “the laws of work”

• Scientific discipline that studies the interaction between humans and theenvironment i.e. the person and their workstation

• Designing the job to match the worker rather than matching the worker tothe job

• Ergonomics covers all aspects of a job, from the physical stresses itplaces on joints, muscles, nerves, tendons, bones and the like, toenvironmental factors which can effect hearing, vision, and generalcomfort and health. 3

Injuries due to PoorErgonomics

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BackacheNeck Pain


What is occupational overuse?

•  Conditions characterised by discomfort or persistent pain inmuscles, tendons and other soft tissues.

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Common problem areas

Back, neck, upper limb…

Cause of injuries:

Repetition and over strain at tendons and joints

Unbalanced and prolonged postures

chronic: cyclic inflammation and weakness

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Common problem areas

The Spine is divided into 5 parts:

•  Cervical Vertebrae - C1-C7

•  Thoracic Vertebrae - T1-T12

•  Lumbar Vertebrae - L1 - L5

•  Sacral Vertebrae (fused) - S1 - S5

•  Coccyx

Normal Spine: S shaped curve

ØEach vertebrae is separated by an intervertebral disc

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Vertebrae

•  The spine comprises of a total of30 vertebrae.

Vertebrae - 2 parts

•  A squat cylindrical portion of boneat the front - acts as the main loadbearing column

•  3 bony processes at the rearwhich provide an attachment pointfor muscles, ligaments and ribs

•  Each vertebra is joined to itsneighbour through two

interlocking pegs known as theFacet Joint

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Intervertebral Discs

•  Act as Shock Absorbers

•  Each disc made up of two parts:

-  Annulus: Outer part of the disc made of a fibrous ligaments. Extremelystrong and responsible for connecting each vertebrae to one another. Actsas a coiled spring

-  Nucleus Pulposus - a soft jelly like centre. Acts as a ball bearing that thevertebrae roll over during flexion, extension and lateral bending.

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•  When you lean forward, the front of the vertebrae come closertogether forcing the disc fluid backwards.

•  When you lean backwards, the back of the vertebrae come closertogether forcing the disc fluid forwards.

•  When you lean to the right, the disc fluid moves to the left. Whenyou lean to the left, the disc fluid moves to the right.

•  This is normal!!

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Owing to our postures during the day, we tend to mainly move into a forward (flexed) position for example:-

sitting at a computer, removing items from boxes, driving the car,cleaning the house, putting on shoes, or relaxing in a sofa.

Therefore the disc fluid is gradually pushed backwards over time. It eventually places increased pressure on the back wall of the disc (toothpaste tube)

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• When the disc fluid starts to place more pressure on the rear wall of the disc, you may start feeling low back pain.

• The more the disc fluid moves backwards, the more pressure is placed on the disc wall which results in the pain being referred further down the buttocks or down the thigh.

• The disc wall may bulge and irritate the nerve causing pain, numbness or weakness down the leg.

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Adjusting the workstation

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Step 1 Start with the chair…

What makes an ergonomic chair

•  5 star base of support

•  Height adjustable base

•  No armrests present

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Height of chair

•  Chair needs to be at a height sothat your forearms are parallel tothe desk with your shouldersrelaxed and elbows at 90 degrees.

•  If your feet can’t reach the floorcomfortably, you require a footrest.

•  Backrest at 90o to 100o to the floor.

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Workplace Ergonomoics

Step 2 The Visual Display Unit (VDU)

•  The VDU should be approximately one arms length away from the user.

•  This is the average focal distance for a person and reduces the need toslouch forward to read the screen

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One arm length


•  The top of the VDU should be ateye-level.

•  People with bi-focalsmay need to have theirVDU lower to avoidexcessive neck extension.

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Eye level


Step 3 The Keyboard

•  The keyboard should be positionedapproximately 8cm from the edge ofthe desk.

•  The keyboard should be locateddirectly in front of the user.

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8cm

Edge of desk

directly in front


versus

• The keyboard should not be inclined to avoid excessive andprolonged extension of the wrist whilst typing.

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x


Step 4 The Mouse

•  The mouse should be positioned to allow the elbow by the side of theuser’s body and the wrist remains in a neutral position.

•  Positioning the mouse too far backwards and to the right (right handdominant people) places the wrist in an unnatural angle which canpredispose the user to carpel tunnel and tennis elbow type symptoms.

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neutral positionthe elbow by the side of body


The Mouse and Keyboard

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Step 5 The zone of frequent use

•  Items used repetitively during theday (for example pens, stapler,punch or telephone) need to beclose enough so that the user doesnot have to stretch for the item.

•  This reduces the risk of slouchingonce the item has been grasped.

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Task & equipment layout

Keying priority

Non-mouse priority

Mouse priority

Phone and writing priority

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Laptops

•  Always adjust the laptop for thescreen height.

•  Preferentially use a laptop stand ordocking station.

•  Use an external mouse andkeyboard.

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Manual Handling

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Plan the Lift

•  Can manual handling aids be used?

•  Where is the load to be placed?

•  Will two people be required to perform the lift?

•  Clear the work area of hazards, obstructions etc

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Plan the Lift

•  Use the large muscles of your legs to lift, let the quadriceps and hamstringsdo the work.

•  Hold the item close to your body and as close to your centre of gravity aspossible

•  Don’t twist with your back, move with your feet. Keep your hips andshoulders in alignment.

•  Pull or push if able, rather that lift.

•  Don’t jerk the load. Lift smoothly.

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Accessing Files and Deskside Cabinets

•  Do NOT sit in your chair, lean to theside and reach for a file.

•  Stand up, bend down with your hipsand knees in front of the cabinetand access the file.

•  Do NOT bend your back

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Pause Stretch Exercises

•  These exercises help reduce the pressure on the intervertebral discs,muscles, joints and ligaments of the spine.

•  They should be performed regularly (every 1-2 hours) during the day.

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Chin Retraction

•  Pull your entire head backwardson your neck

•  Your chin should not go down or upbut directly backward

•  Hold 2 seconds then relax

•  Do not poke the chin forwards

•  Repeat 10 times approximately everyhour

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Back Bend

•  In standing, place your hands on yourbuttocks

•  Lean backwards trying to bend yourback just above your buttocks

•  Hold 2 seconds then straighten up

•  Repeat 10 times approximately everyhour

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Reach for the Ceiling

•  Clasp your hands togetherand turn them inside-out

•  Reach to the ceiling

•  Hold 10 seconds

•  Pull hands backwards or sidewaysand hold a further 10 seconds eachmovement

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Forearm Stretch

•  Hold your arm straight out in front ofyou

•  Pull your hand upwards


•  Pull your hand downwards


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Shoulder Rolls

•  Rotate your shoulders backwardsapproximately 20 times

•  Emphasise a good posture whiledoing the stretch

•  Don’t roll your shoulders forward asthis emphasises poor posture

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Thoracic Extensions

•  (To be performed in a chair with a

30-50cm backrest)

•  Support your head in your hands.

•  Slowly and gently lean backwards in

your chair.

•  Hold 2 seconds.

•  Slide approximately 3cm down the

chair. Slowly and gently lean

backwards again.

•  Repeat along your thoracic spine to

just below your neck.

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QUESTIONS?

1. Ergonomics applies to:

a) Workstation design and how work is organized

b) Working postures and handling manual materials

c) Tools, equipment and furniture design

d) Temperature, humidity and lighting

e) All of the above

2.The primary risk factors for musculoskeletal injuries are

a) Repetitive movements

b) Forceful movements

c) Fixed or awkward postures

d) Bending, twisting and heavy lifting

e) All of the above

3.While working at your workstation, usual work should be kept within forearm length.

a) True

b) False

4.One of the ways I can protect myself from a back injury is by

a) Testing the object before lifting

b) Keeping the load close

c) Not twisting at the waist when lifting

d) Lifting the load with a partner

e) All of the above

5. Which is the proper way of lifting heavy object?

A B

Terima Kasih

workplace ergonomics

Documents

disc fluid forwards

l5 sacral vertebrae

cervical vertebrae c1

total of30 vertebrae

c7 thoracic vertebrae

t12 lumbar vertebrae

s shaped curveeach vertebrae

job ergonomics