Wednesday, May 28, 2008

Choosing & Adjusting an Ergonomic Chair

The human body was not designed to keep still for long periods of time. And yet, the majority of American workers spend hours sitting in a chair while performing job activity. While sitting, the large muscles of the back, shoulders and neck contract to support the active movement of the arms and hands. This constant contraction can lead to fatigue and trigger points in the muscles. A good seating system can help alleviate this risk.

A good seating system allows for adjustability between body types. However, one size does not always fit all. A worker who is petite or larger may need to seek out special chair sizes that accommodate their body frames.

Here are some common adjustments that your office chair should be able to make.


1. Height - The chair should be able to be raised and lowered easily. Height is the first adjustment that should be made. When looking at the proper height of the chair, the elbows should be slightly higher than the work surface (desk or keyboard) so that the elbow is opened slightly greater than 90 degrees. The feet should be placed flat on the floor and the work surface adjusted (such as with an adjustable keyboard tray) if possible. However, if the work surface is not adjustable then the height of the work surface dictates the height of the chair. In this case, a footrest may be necessary to support the feet.

2. Depth of Seat Pan - The seat pan should slide forward and back to accommodate for differences in thigh length. If the seat pan is too shallow then body weight will not be distributed evenly through the thighs. If the seat pan is too deep or too narrow, you will be more likely to sit forward on the edge of the chair rather than taking advantage of the support of the chair back. The seat pan should also be rounded so that sharp edges do not press into the thighs and impede circulation. You should have a space of 2-3 fingers width between the edge of the chair and the back of the knee so that pressure is not placed on the nerves of the leg.

3. Back Support - The back of the chair should be able to be adjusted higher or lower to accommodate for a variety of heights. Proper lumbar support will help maintain the natural curves of the back and reduce the risk of back pain.

4. Seat Pan Tilt - Tilting the pan of the seat will allow you to accommodate for a variety of job tasks while still maintaining lumbar support. It will also allow you to vary working postures throughout the work day. Recent studies are now showing that a mild recline in a supported position is healthy for the back and reduces back pain. Slouching, however, reduces spinal disk height causing wear and tear on the lowest two spinal levels.

5. Arm Rests - The arm rests should raise and lower so that they support the forearms without causing the shoulders to be lifted towards the ears. A good chair will also have arm rests that can swivel or be pushed out of the way if needed. Arm rests should be broad and padded so that the forearm does not press into sharp edges.

6. Chair Base - Any rolling office chair should have a 5-point base of support for safety and stability.


A few more tips to help you remain pain-free while sitting at your desk or workstation -


* Visit an office supply store and take the time to sit in a variety of chairs to get the feel for one that is comfortable for you.

* Look for suppliers who have sample chairs that you can test for several weeks in the office environment.

* Learn to use the adjustments.

* Get up often and stretch frequently to increase circulation and reduce muscle fatigue.

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Thursday, May 15, 2008

Laptop Ergonomics

Laptop computers and portable technology have changed the way we do business.  With portable equipment, we are now able to work away from our primary office in a temporary or more comfortable location.  We now have the luxury of working in a secondary or off-site office, while traveling, from the comfort of our home, and while lounging on the couch.  However, in spite of their many benefits, portable computers, by their nature, increase the risk of developing repetitive strain injuries. 
  • The keyboard and screen are attached in one unit.  Because they are unable to be adjusted independently, an ergonomic compromise is created on positioning and comfort of either the neck or the arm.
  • Laptops are often used in cramped spaces compromising posture.
  • Laptop keys are smaller than traditional, desk-top keyboards causing the potential for increased hand and finger strain.
  • Laptop screens are typically smaller than standard causing potential eye strain.
  • It is harder to adjust the laptop screen to reduce glare.
  • Portable equipment is heavy to carry.

These shortfalls create the risk for pain, aching and muscular fatigue in the neck, shoulders, back, elbows, wrists and hands.  They also create the potential for eye strain, headaches, numbness and tingling in the arms.

Putting these simple ergonomic adjustments into practice can help you reduce the risk of developing injuries while working on your laptop.
  • Stretch often.
  • Be aware of posture.
  • Take frequent breaks, every 20-30 minutes if possible.
  • Change your position often.
  • Switch the laptop position from the lap to the table every 30 minutes. 
    • Putting the laptop in your lap will relax your shoulders. 
    • Putting it on the table will relax the neck and reduce eyestrain.

  • Limit the peripherals you carry to the bare essentials to reduce the weight you carry.
  • Use a carrier with padded straps and frequently change the shoulder that the bag is carried on; or use a backpack with both straps over the shoulders to distribute the weight; better still, use a carrier with wheels.
  • Follow standard ergonomic positioning for a keyboard as closely as possible.
    • Keep the wrists neutral.
    • Keep the elbows open to 90 degrees or slightly greater.
    • The ears, shoulders and elbows should be in vertical alignment.
    • The shoulders should be relaxed.  Do not round shoulders forward or hunch them up towards the ears.
    • The head and neck should be relaxed.  Do not let head drop forward out of alignment with shoulders.

  • Use proper finger positioning, typing & mousing techniques.
    • Use two hands for 2-key functions.
    • Use the stronger fingers (modified hunt and peck) rather than stretching the fingers to reach for keys.
    • Keep the fingers relaxed.
    • Use a light touch while typing.
    • Movements should come from the larger shoulder muscles.  Do not isolate the smaller wrist and hand muscles while typing by planting the wrists down.

  • Prevent eye-strain and headaches.
    • Frequently look away from the screen and look at an object far in the distance.  Follow the 30-30-30 rule.

      • rest the eyes for 30 seconds
      • by looking 30 feet away
      • for every 30 minutes of typing

    • Rub your hands briskly together until warmth is created and then place your warm palms over closed eyes.  Hold the position for 20 seconds.
    • Frequently clean the screen using the appropriate antistatic cleaners.
    • Adjust font for color, contrast and size so that reading the screen is comfortable.

    If you use the laptop as your primary computer, it is especially important to be aware of your positioning.  
    • When you are in your office or primary work environment, elevate the laptop using monitor risers so that the screen in an optimal position and you do not need to bend your neck when looking at the screen; then, connect a separate keyboard and mouse at elbow level to position the arms appropriately.
    • When sitting in a chair without elbow supports or a couch, use pillows to support the arms whenever possible.  Keep the same general ergonomic positioning guidelines in mind even if you are in a relaxed work environment.

    The following exercises will help you stay flexible and keep you pain-free.
    • Stretch the thumb by gently pulling it back.  Hold for 20 seconds.
    • Stretch the palm up.  Hold for 20 seconds.
    • Perform basic forearm stretches. 

      • Place your hand out in front of you as if you are saying “stop” and pull the fingers gently back with the other hand.  Hold for 20 seconds. 
      • Now let gravity drop the wrist down and gently increase the stretch by pulling with the other hand.  Hold for 20 seconds.

    • Stretch the triceps and biceps stretches.
    • Perform shoulder and neck stretches.
    • Stretch the back.
      • Gently interlace the fingers behind the neck and arch your upper back as if you are trying to look up at the ceiling (be careful not to pull the head forward).  Hold for 20 seconds. 
      • Place your hands on your hips and arch the lower back as if you are trying to look up at the ceiling.  Hold for 20 seconds.

    • Perform 15-20 minutes of daily cardio activity to improve circulation and oxygen flow to the arms for improved conditioning and better healing.
    • Perform core strengthening exercises to improve general postural stability.

    Check out these samples of a laptop stand, ergonomic carrier and wheeled carrying case available from Amazon.com.


    And a very cute laptop charm -



    Marji Hajic is an occupational therapist and a certified hand therapist practicing in Santa Barbara, California. For more information on hand and upper extremity injuries, prevention and recovery, visit Hand Health Resources.

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  • Tuesday, May 06, 2008

    Global Warming and Barometric Pressure

    The Center for American Progress has listed the Top 100 Effects of Global Warming. Global warming is being blamed for everything from killing the planet with glacial melting to threatening species of animals and negatively impacting our agricultural production. We are being warned that global warming will threaten our health with an increase in heat stroke, heart attacks, infectious diseases and smog/allergy related conditions. I would like to (jokingly) add an increase in carpal tunnel syndrome and other computer-related pain syndromes to the top 100 list of global warming effects.
    Increases in severe weather are predicted as a response to global warming. Weather.com now offers a link to an aches and pains forecast that predicts how weather factors affect the way people feel. According to weather.com, the connection between weather and health dates back to Ancient Greece when the effect of hot and cold winds on pain and illness were described over 2,400 years ago.
    Although recent studies are inconclusive, all of us know of that elderly relative who accurately predicts rain because of an aching knee or shoulder joint. Some people appear to be more weather sensitive than others. For most of us, the sensitivity to weather occurs as a result of the change in weather rather than from any specific weather condition. Personally, I know that barometric pressure changes will bring more reports of pain on any given day in the therapy clinic.
    Barometric pressure is the measurement of the weight of air molecules around us. When the weather changes the weight of the air molecules change. A rapid fall in pressure signals the onset of stormy weather. This change is highly correlated with an increase in body aches and pains. As the barometric pressure drops, the gas and tissue around injured or inflamed joints can increase resulting in more pain.
    So, if you are prone to computer-related pain, plan to weather the storm by taking extra precautions during the time of barometric pressure changes. Be particularly aware of your posture, positioning and work methods; take frequent breaks; stretch often; and use you choice of over-the-counter anti-inflammatory medications as needed. Heat or cold packs can also be helpful.
    And it certainly won’t hurt to live green.
    Marji Hajic is an Occupational Therapist and a Certified Hand Therapist practicing in Santa Barbara, California. For more information on hand and upper extremity injuries, prevention and recovery, visit Hand Health Resources.

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