Computer Ergonomics

What is Ergonomics?

Scientific study of relationship between people and machinery.

Understanding of the interaction between human being and a machine.

Why is Ergonomics important

In order to optimize human well-being Improve work performance by removing

sources of muscular stress and general fatigue

Preventing injuries Musculoskeletal disorder (MSD)

injuries and disorders of the musculoskeletal system

repetitive, forceful or prolonged exertions Carpal tunnel syndrome (CTS)

a compression of the median nerve in the wrist

Posture Safe and comfortable No single “correct” posture fits everyone However, there are some guidelines

Top of monitor at or just below eye level Head and neck balanced and in-line with torso Shoulder relaxed Elbows close to body and supported Lower back supported Wrists and hand in-line with forearms Adequate room for keyboard and mouse Feet flat on the floor

Ideal Posture

Ergonomics Equipments Chair Pointing Device Foot Switch Keyboard Accessories

Document Holder Wristrest Footrest Anti-glare Guard

Environmental Factors Lighting

Light source Don’t face or back to a bright window Use anti-glare screen

Light level Noise

Work in a quiet place Use low volume classical music

Air quality Make sure there is enough fresh-air

ventilation Room temperature at comfortable level

Adjust Chair adjust your chair to suit YOU! chair should have a seat that curves down in the

front: the seat should not touch the underside of your thighs;

chair should have an adjustable back rest and is able to support the back in a variety of seated postures

chair should be lowered/raised: highest point of seat = just below knee cap

legs are perpendicular to floor, and keep feet flat on the floor, or supported on a footrest.

Armrests, if provided, should be soft, allow your shoulders to relax and your elbows to stay close to your body

Chair: Potential harms and solutions - I Harm: Poor back support and

inappropriate postures may lead to back pain and fatigue

Solution: 1. Use a chair with a backrest that is easily

adjustable and able to support the back in a variety of seated postures.

2. Use a rolled up towel or even a pillow to temporarily provide support and maintain the natural curve of the spine.

Chair: Potential harms and solutions - II Harm: Using a chair that is too high may

lead to swelling, numbness, and pain because your feet are not supported and may move forward making your spine difficult to maintain S-shape.

Solution: 1. If chair is adjustable, make the highest

point of seat at just below knee cap 2. If chair is not adjustable, use a footrest

Chair: Potential harms and solutions - III

Harm: armrest, too low, high, wide, and close, can result in muscle fatigue in the shoulders and neck

Solution: use position adjustable armrests if possible

Adjust Keyboard elbows and forearms should form 90

degree angle forearm is in line with keyboard’s Home

Row wrists should NOT be leaning on the desk wrists should be loosely bent downward

over the Home Row Problems: carpal tunnel syndrome in wrist

Mouse Position the mouse pad as close to your

keyboard as possible and at the same height.

Hold mouse loosely. Use the whole arm and shoulder to move

the mouse. This spreads the work over larger muscles, not just the small hand muscles.

Avoid leaning on the wrist and arm when using the mouse.

Adjust Monitor top of monitor = eye level reduce reflections from monitor:

don’t wear white clothing don’t place your back to windows (use

curtains, shades, blinds) use anti-glare filters adjust brightness/contrast buttons on

computer use directional light on documents

“document holders” at same level as monitor

Problems: sore eyes; itchy eyes; tiredness

Use of telephone - I

Potential Harm: placing the telephone too far away can cause you to repeatedly reach, resulting in strain on the shoulder, arm, and neck.

Solution: Place telephone in the area you can easily reach. Keep the telephone cord out of working areas so it does not trap you.

Use of telephone - II

Harm: long conversations with the phone pinched between your shoulder and head may cause stress and neck pain

Solution: use hand-free headset if you can

Exercises – I Knee Kiss

Pull one leg to your chest, grasp with both hands and hold for a count of five. Repeat with the opposite leg.

WindmillPlace your feet apart on the floor.Bend over and touch your right hand to your left foot, with you left arm extended up.Repeat with opposite arm.

Exercises - II Back Relaxer

Bend down between your knees as far as you can.Return to upright position and relax.

Prectoral StretchGrasp your hands behind your neck and press your elbows back as far as you can.Return to starting position, then drop your arms and relax.Repeat.

Exercises - III Middle-Upper Back Stretch

Raise your right arm and grasp it below the elbow with your left hand.Gently pull your right elbow toward your left shoulderas you feel for the stretch.Hold for five seconds. Do both sides.

Side StretchInterlace your fingers.Lift your arms over your head, keeping your elbows straight. Press your arms backward as far as you can. Then slowly lean to the left, and then to the right, until you can feel the stretching.

Exercise - IV Fingers

With palms down, spread your fingers apart as far as you can.Hold for the count of five. Relax.Repeat.

Shoulder RollSlowly roll your shoulders forward five times in circular mothing, using your full range of motion. Then roll your shoulders backward five times with the same circular motion.

Exercises - V Neck

Let your head drop slowly to the left, then to the right.Slowly drop your chin to your chest, and then raise your chin as high as you can.Turn your head to the left, return it to the normal position, then turn it to the right.

QuadricepsBring your legs straight out in front of your body, and then hold them in that position for five seconds. Make sure you are sitting up straight. Relax.Repeat.

Useful Links

Kinesis Computer Ergonomics, http://www.kinesis-ergo.com/

U.S. Department of Labor, http://www.osha.gov/SLTC/etools/computerworkstations/