Ergonomics

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Ergonomics

Ergonomics

What is ergonomics?

Ergonomics is the science of designing the job, equipment, and workplace to fit the worker. It is concerned with the ‘fit’ between people and their technological tools and environments. It takes account of the user's capabilities and limitations in seeking to ensure that tasks, equipment, information and the environment suit each user.

Why are ergonomics important?

Ergonomics is an important factor in maintaining physical wellness. It provides guidelines on the prevention equipment and treatments that promote physical wellness. Proper ergonomic design is necessary to prevent repetitive strain injuries, which can develop over time and can lead to long-term disability. 

Many people do not realize that poorly designed computer workstation and bad work habits can result in serious health problems.

What can happen if I don't use proper ergonomics?

Common problems associated with poor design or habits include discomfort in the back, neck, shoulders, hands, wrists, in addition to headaches and eyestrain. Individuals regularly working with computers should pay special attention to these symptoms.

Many different disorders can arise from gradual development of small injuries or stresses to the body and are generally referred to as Cumulative Trauma Disorders (CTDs). CTDs are prevalent among today’s electronic work environment and are often referred to as repetitive stress injuries (RSIs), work-related musculoskeletal disorders (MSDs), repetitive motion injury (RMI), or occupational overuse syndrome. They are the cumulative product of many smaller injuries over time. There are several risk factors that can lead to these disorders including:

  • Repetitive motion
  • Prolonged awkward postures
  • Excessive force
  • Contact stressors
  • Inadequate recovery time
  • Personal risk factors (i.e. stress, poor diet, lack of exercise)

If you are developing a CTD, you may begin to experience one or more symptoms in the affected region of your body. These symptoms may include numbness, pain, swelling, tingling, aching, burning, or loss of strength. Some common forms of CTD that affect computer users are Carpal Tunnel Syndrome and tendonitis.

Vision

Improper light sources can create glare on the monitor's screen. Staring at a computer monitor for extended periods of time can cause physical problems. Because the characters on a computer screen are different than the printed page, they can cause eyestrain. The resulting eyestrain can cause:

  • Headaches
  • Fatigue
  • Blurry or double vision
  • Burning and dry sensations
  • Ocular fatigue
  • Loss of focus.

No permanent eye damage has been attributed to computer use.

Neck

Neck strain can result from the following:

  • Looking up at a monitor that is placed too high
  • Viewing a monitor placed too low or viewing a document on the desk
  • Looking over to one side to view a monitor or copy from a document
  • Putting your chin forward to view a screen or copy from a document
  • Holding the phone between the ear and the shoulder places a lot of stress on the joints and muscles (it's called Handset Fatigue).

These issues can make your neck feel stiff, tight and achy and develop into degeneration of the joints of your neck (osteoarthritis) and tension headaches.

Back

The back's muscles, ligaments and discs can be strained from sitting improperly and from sitting unsupported for long periods. Joints can get stiff and dysfunctional if they are being held in one position for multiple hours each day. The spine joints are particularly susceptible to strain when the spine is held in prolonged, awkward postures. Improper posture while sitting can strain the ligaments in the spine that support the joints and create stiffness and inflammation in a joint. The result is back pain, and it can be contributed by the following factors:

  • Sitting slumped
  • Lack of support from your chair
  • Improper fit of the chair / improper type of chair for computer use
  • Feet not touching the ground
  • Prolonged sitting without a break
  • Over reaching for the keyboard or mouse

Arms and Wrists 

Repetitive Stress Injury (RSI) or Cumulative Trauma Disorders (CTD) are the result of the effects of constant and consistent repetition of movement and exertion on particular parts of your body.

Warning signs are pain, tingling, numbness or weakness located between the neck and hands.

Untreated, symptoms can progress from unusual clumsiness associated with weakening muscles to irreparable nerve damage.

The result can be Carpal Tunnel Syndrome (CTS).

When can I use proper ergonomics?

  • Typing on your computer or laptop
  • Sitting at your desk
  • Studying in the library / at home
  • Carrying a back pack
  • Reading
  • Lifting
  • Pushing and Pulling
  • Standing

What can I do to be ergonomically correct?

There are many things that you can do to prevent CTDs. These prevention methods are important because it is easy to be unaware that you are causing your body harm.

Chairs

Maintaining good posture while using a computer can prevent a host of discomforts across your body, especially back and lower limb pain. This does not mean you should maintain the same posture the whole time you are sitting.

  • Strive to vary your sitting postures.
  • Take periodic breaks that involve getting up for your seat. 
  • When sitting in your chair you should have a 90 degree bend at your knees when your feet are flat on the floor.
  • Your chair should support your back as you sit upright. It is okay to recline the chair back slightly, but too much can strain the neck as you try to right your head to view the monitor if you are using a computer.
  • Make sure that you are sitting back in the chair and that the head is aligned over the shoulders

Monitors

  • Your monitor should be directly in front of you in line with the keyboard (never to the side where you must twist to view the screen).
  • Typically the top of the screen should be at or a little below your eye level. This promotes a natural downward angle view.
  • The monitor should be at about arm’s length away from your body, give or take a little depending on your comfort.
  • The recommended distance away between the eyes and the screen is 18-30 inches away (if you have vision problems, you may have to move the screen closer / further away).

Keyboards

  • The keyboard should be at or slightly below elbow height, and parallel with your forearms.
  • If your keyboard has feet on the back that prop it up, make sure to lower those feet in order to keep your wrists straight.
  • If you have an adjustable keyboard tray, don't use a positive slope (i.e., the back of the keyboard is higher than the front). THis creates an unnecessary bend in your wrist.
  • Use a slight negative slope (i.e., the front of the keyboard is higher than the back) can help promote straight wrists and is often suggested for people who are experiencing mild wrist pain.
  • Position equipment and work tasks so that your body is directly in front of and close to your major work tasks.
  • Do not pound on the keys, instead use as light a touch as possible.
  • Use as little wrist motion as possible.

Mouse

  • Position mouse as close to the keyboard as possible, and at the same height.
  • Avoid resting your forearm or wrists on a sharp edge or hard surface. The constant pressue may lead to discomfort.
  • If you are experiencing fatigue or soreness in your mousing hand, try using shortcut keys more frequently instead of the mouse. 
  • Try an alternative mouse such as trackball or touch pad.
  • Use free-moving mouse that fits your hand. You should not have buttons that are awkwardly placed and move easily. 
  • Don't hold a mouse or pointing device too tightly or for too long.

Laptops

The clamshell construction of the laptop computer makes it nearly impossible to set up without placing stress on some area of the body. For example, since the keyboard and monitor are attached, the user must choose between having the monitor at the correct viewing height (to prevent neck strain) versus having the keyboard at the correct height (to prevent shoulder or wrist strain). Additionally, the keyboard or a laptop computer is typically much smaller than a standard keyboard and can cause the user to keep the wrists in an awkward position while typing. For these reasons and more, it is important to see ways to minimize these ergonomic stresses during periods of intense typing.

Using your laptop at your primary desk
  • Use an external keyboard when sitting at your primary desk. This will allow you to adjust the monitor and keyboard independently
  • Strive to place your keyboard so that your elbows form a 90 degree angle when you are typing.
  • Consider using an external mouse and make sure it is located on the same level and directly next to the keyboard.
  • Adjust the height of your monitor so that the top of the screen is at your eye level. You can achieve this by placing a stable object (such as a book) underneath the laptop, or by using one of the many specialty products on the market designed for this purpose.
Using your laptop at a temporary location (classroom, library, study lounge)
  • Raise the back of the keyboard so that the entire laptop is tilted slightly to improve viewing height and angle. It is also allows an improved position of the shoulders and arms for keyboarding.
  • Strive to use the same principles at your primary desk.
  • In hotels and on airplanes you can use pillows and blankets to raise your height to achieve the proper position for your arms and wrists.
  • It is not ideal to work in a temporary location for long periods of time.

Reading

  • Reduce overhead lighting
  • Close blinds over windows.
  • If reading documents on your computer or laptop, clean screen to minimize glare and increase character sharpness.
  • If you wear contacts, blink often and use artificial tears to reduce eye irritation.

Backpack

  • Make sure your backpack weighs no more than 5-10 percent of your body weight.
  • A heavier backpack will cause you to bend forward in an attempt to support the weight on your back.
  • The backpack should never hang more than four inches below the waistline. This will increase the weight on the shoulders.
  • A backpack with individual compartments help make sure that objects are packed away from the area that will rest on your back.
  • Bigger is not necessarily better. The more room there is in a backpack, the more you will carry and the heavier the backpack will be.
  • Wear both shoulder straps. Using one stap can lead to neck / muscle spasms and low-back pain.
  • Wide, padded straps are very important. Non-padded straps are uncomfortable, and can dig into your shoulders.
  • The shoulder straps should be adjustable so the backpack can be fitted to your body.
  • Straps that are too loose can cause the backpack to dangle uncomfortably and cause spinal misalignment and pain.

Moving Objects

  • Do not lift the item if it is too big or too heavy.
  • Stand in front of the load with your feet shoulder-width apart with toes pointed outward slightly.
  • Bend your knees and squat. Stay as close to the load as you can.
  • Get a good grip. Tighten your stomach muscles, but don’t round your back.
  • Lift from your thighs and knees, not your back.
  • Lift slowly and smoothly. Don’t jerk.
  • Keep your back straight, do not twist.
  • Hold the load close to your body while you carry it.
  • Bend from the knees when you set your load down. Remember to keep your back straight.

Lifting Objects Down

  • Start by standing on a sturdy stool to raise yourself up. 
  • Lift one corner of the load to test its weight. If it’s too heavy, call for a taller and stronger person.
  • If object is not too heavy, grip the load firmly with both hands and tighten your stomach muscles.
  • Bring the load down slowly and smoothly.
  • Set it down on a table or counter. Don’t twist your waist to get there. Turn with your feet if you need to turn.
  • Stop and adjust your grip if you need to move the load to the floor. 
  • Keep your back straight, bend your knees, and squat to lower it down.

Pushing

  • Pushing is much easier on the back than pulling, so always push a load if you have the choice.
  • Push with both arms bent.
  • Stand as close to the load as you can. 
  • Don’t lean over or reach out to push.
  • Use both hands and bend your elbows.
  • Push with your legs, not your back.
  • Take small steps.

Pulling

  • Pull without arching your back.
  • Stand close to the load. Don’t lean over or reach out to pull.
  • Pull from your legs, not your back.
  • Take small steps.
  • Think of a string running down between your ears, shoulders, and hips - try to keep the string in a straight line.
  • Wear comfortable, low-heeled shoes.
  • Bend your knees a little bit. Hold your stomach in.
  • Spread your weight evenly on both feet.
  • Stand close to your work so you don’t have to slouch over it.
  • Rest one foot on a low step or rail when standing for a long time. Switch feet every few minutes.
  • Stand on a floor mat or rug when you can.

What else can I do?

Take stretch breaks! 

Take a break periodically throughout the day and stretch. Stretching helps divide up repetitive activities, relieve tension and gives fatigued muscles a chance to recover. Here are some ideas for stretches you can do at your desk:

  • Raise the tops of your shoulders towards your ears and hold for 5 seconds. Release. Repeat 5 times.
  • Tilt your chin towards your neck and hold for 5 seconds. Release. Repeat 5 times.
  • Turn your head towards your right shoulder. Hold for 5 seconds and release. Repeat on the other side. Repeat 5 times on each side.
  • Clench your hands into a fist and hold for 5 seconds. Release, separating and fanning out your fingers until you feel a stretch. Hold for 5 seconds and release. Repeat the entire cycle 5 times.

Additional Resources

OSHA Workstation Safety

CDC Ergonomics

Backpack Misuse