Computer Ergonomics

In the past I have written many ergonomic articles that harp on the importance of posture in the development of repetitive stress injuries (cumulative trauma disorders).

Most cases of repetitive stress syndrome involve the neck, shoulder, elbow, wrist and hand. Collectively this region is referred to as the upper extremity. Depending on the type of work you do, different portions of the upper extremity can be involved in your group of symptoms.

There is no list that links the type of job that you perform with a specific set of injuries that will develop as a result of that exposure. That being said, there are some jobs that are notorious for causing specific repetitive stress syndrome type symptoms - keyboard operators and carpal tunnel syndrome and construction workers and shoulder tendonitis come to mind as typical cause and effect examples.

Almost all types of repetitive stress involve some combination of postural stress, excessive force and repetitive motion.

Jobs that require people to either assume prolonged fixed positions (computer workers) or awkward positions (auto mechanics) generate significant amounts of biomechanical stress to the joints and soft tissues of the upper extremities. Usually postural stress results from overloading of specific muscle groups, uneven weight loading of joints or by assuming positions that require static muscular contractions to limit joint motion in a specific area of the body.

Muscular force without adequate recovery time is another major contributor in the development of repetitive stress injuries. Some jobs require prolonged contraction of certain muscle groups, which reduces blood circulation resulting in fatigue. Muscles do not work efficiently under these conditions and without adequate recovery time will result in injury.

Highly repetitious movements of specific joints also contribute to repetitive stress syndrome. High frequency movements demand faster and stronger contractions of the muscles. Joints and muscles that are required to work in these conditions require more recovery time. Without adequate recovery time injury to the joints, muscle and tendons occur.

All of the factors listed above have to be taken into consideration when designing a work area and work duties. Taking frequent breaks, rotating job duties and getting much needed rest will all help in keeping you healthier and more productive through the course of your work life.

Here’s To Your Health

Dr. Jones

Economical Adjustable Mouse Platform
San Diego Chiropractic
Pain Relief San Diego Chiropractor

This is the final installment in this series of blog posts. My next series will examine different job duties and how they lead to cumulative trauma disorders.

What are the Common Symptoms of Cumulative Trauma Disorders?

· Tightness, discomfort, stiffness, soreness or burning in the hands, wrists, fingers, forearms, or elbows

· Tingling, coldness, night pain or numbness in the hands, especially around the base of the thumb

· Clumsiness or loss of strength in the hands

· Pain in the neck, shoulders, wrists, hands or back that is associated with using the computer

How Can You Avoid Injuries Related to Reaching for the Mouse?

The following recommendations are applicable to both home office ergonomics as well as ergonomics in the office.

1) Placing the input device directly in your immediate reach zone offers natural comfort and maximum hand-eye coordination. The use of a platform for the mouse is preferable. Some models of mouse platforms attach directly to your chair.

2) Your chair should have arm rests that are adjustable.

3) Your wrist should be either in a neutral position or flexed slightly downward when operating both your mouse and your keyboard. For this reason, if you select a mouse platform that attaches to your chair, adjustability of the platform is of primary importance.

4) Consider using a high quality office chair with adjustable armrests and lumbar supports. It should also allow some degree of recline.

5) Make sure that the upper arm and elbow are as close to the body and as relaxed as possible for mouse use - avoid overreaching.

6) Hold the mouse lightly, don’t grip it hard or squeeze it. Place the pointing device where you don’t have to reach up or over very far to use it. The closer you can place it to your body the better.

These are just a few ideas that might help you to either get out of pain or be of use in your efforts to prevent the onset of cumulative trauma disorders. I hope that this information is helpful to you all. Remember - KNOWLEDGE IS POWER!

More Coming Soon

Dr. Jones

Economical Adjustable Mouse Platform
San Diego Chiropractic
Pain Relief San Diego Chiropractor

The study of workstation ergonomics tells us that the objects that we use most often should be located closest to your body and accessed easily, without awkward body positions or movements. Repeated reaching or prolonged fixed postures that involve leaning forward from your chair are stressful and fatiguing.

Some people are aware of computer ergonomics and have purchased various ergonomic devices. These devices, such as keyboard trays, gel mouse pads, and ergonomic keyboards rarely provide solutions to the big picture of computer ergonomics. These items must work with each other in order to produce a significant reduction in postural stress. For example, an ergonomic mouse is of little use if it is positioned in an area that requires reaching and stretching in order to operate it. Limiting reaching and stretching for desk items is essential to maintaining a healthy ergonomic environment.

The most frequent complaint that I have seen in my office is due to computer work is the combination of mousing and reaching to the desk for the mouse.

Most computer stations are designed in a way that involves the worker operating the computer mouse on a pad on the desk. Reaching to the desk for the mouse places direct stress on the joints and soft tissues of the neck, shoulder, elbow, wrist and hand. Additionally, reaching forward for the mouse stresses the lower and middle back.

So How Does Reaching for the Mouse Set the Stage for Injury?

Reaching for the mouse causes you to lean forward in your chair, extend your arm and support the weight of your body through your extended arm.

The stresses placed on the human frame when reaching for the mouse are easily identified. Contrary to popular belief, sitting, which most people believe is relaxing, is hard on the back. Sitting for long periods of time can cause increased pressure on the discs of the spine.

In recent years, studies on postural stress have indicated that we should be sitting upright with our hips flexed at 90 degrees. As it turns out, the most up to date studies show that a slightly reclined sitting posture with the hips flexed at 100 to 115 degrees is ideal if you have to sit at a desk. If your mouse is not positioned close enough to your body, you will have to reach for it. Reaching for your mouse stresses your back by reducing the angle of your hips.

Next, we have to look at the effects of reaching on the neck and shoulder. When the mouse is being operated at a distance that makes the operator reach, the shoulder extends forward and the shoulder blade abducts (rotates forward). This position stretches the muscle groups that connect the medial portion of your shoulder blade to your spine and the superior portion of your shoulder blade to your neck. In the short term, this stretch aggravates the affected muscle groups causing spasm, fatigue, headaches and stiffness in the neck and shoulder. In the long term, this position creates a condition called a “stretch weakness” resulting in muscular imbalance, trigger points and chronic variations of the conditions listed in the prior sentence.

Lastly, placing the mouse too far away, too low, or too much on one side can cause shoulder, wrist, elbow, and forearm discomfort. When the operator is forced to reach for the mouse, his / her body weight shifts forward and ultimately results in weight bearing stress on the extended arm. Spending prolonged periods of time leaning on an extended arm is an unnatural and destructive posture that will eventually lead to the development of a repetitive stress syndrome; likely resulting disorders would include tendonitis of the wrist, elbow or shoulder.

Here’s To Your Health

Dr. Jones

Economical Adjustable Mouse Platform
San Diego Chiropractic
Pain Relief San Diego Chiropractor

Hundreds if not thousands of books and articles have been written that deal with the short and long term negative effects of working with computers.

As a chiropractor practicing in San Diego, I see a constant flow of new patients who complain of neck pain, shoulder pain, arm pain, wrist pain and hand pain as a result of long work days that mostly consist of sitting at a computer. It doesn’t stop there. Because sitting is especially stressful for the lower back we see plenty of computer operators who complain of low back pain as well.

It seems that the computer spares no body part from pain, discomfort and sometimes disability.

The most damaging characteristics of computer work can be summed up in two related triggers that stimulate our bodies to react to this type of work.

The first of these triggers involves the way the muscles of our necks, upper backs, arms and hands are used during computer work.

Whenever we are working on our computers our fingers are moving a mile a minute while the rest of the muscles of our upper extremities are in a static contraction. Muscles are designed to move joints through an entire range of motion. When we work at our computers these muscles simply contract to hold joints in a fixed position. When muscles act in this way they build up lactic acid, become irritated and inflamed and eventually fatigue and become painful. The long-term effects of this process include tendonitis, carpal tunnel syndrome, trigger finger, etc, etc.

The second trigger involves postural stress. It is human nature to lean forward into our work. Leaning forward improves our ability to see what we are working on. This posture typically includes bending forward at the waist, rounding our shoulders forward and craning our necks forward. Each of these body positions by themselves is capable of causing pain and discomfort. When we are doing computer work it is not unusual to have all three of these postural stresses working on us at the same time.

Controlling these stresses is of utmost importance in order to prevent injury. Taking short one or two minute stretching breaks for the arms and hands every twenty or thirty minutes is very helpful. Icing the painful areas is helpful as well. Finally, becoming aware of your posture and doing what you can to eliminate postural stress will help.

There are other articles on this topic in this blog and in my chiropractic blog at www.jonespainrelife.com/blog that will give you more information on how to control the stresses of computer work.

Here’s To Your Health

Dr. Jones

Economical Adjustable Mouse Platform
San Diego Chiropractic
Pain Relief San Diego Chiropractor

Is your computer making you feel like you are losing a war?

For many of us who spend increasing amounts of time sitting at a computer, the answer to the question above is yes.

Postural stress is a major component of the cases of back pain that I see in my practice. Anyone who spends enough hours in enough days sitting in a static position at a computer station is bound to develop pain as a result of this stress.

Years ago I developed, patented and produced a mouse platform that was intended to reduce the chances of the development of carpal tunnel syndrome. Those of you who have read my previous blog posts are familiar with this story.

In a nutshell, I saw my patients struggle with many work related stresses due to computer use. Of these complaints, the most common complaint was the shoulder pain, neck pain, arm pain, wrist pain and hand pain that resulted from reaching to the desk for the mouse. I thought of an idea to eliminate the reach for the mouse and that thought resulted in the birth of my first patent, the Ergo Nav.

The Ergo Nav turned out to be very successful in reducing the stresses that it was intended to help relieve. However, there was a second positive effect that I had not really thought out prior to the initial months of testing this new way of mousing.

By positioning the mouse next to the operator as the Ergo Nav does, postural stress on the low back was reduced thus reducing fatigue of the lower back and, hence reducing low back pain.

For years it was thought that the proper hip angle of a seating posture was 90 degrees. Now, however, that angle is known to be too small. A proper angle of the hips in a seated posture is from 95 degrees to 115 degrees. This angle has your chair back tilted slightly backward, away from your desk, keyboard and mouse.

The Ergo Nav helps the worker maintain this angle of the hips by keeping the mouse at constant distance from the operator. In other words, the Ergo Nav allows the operator to tilt the chair at the proper angle without moving away from the mouse.

Here’s To Your Health

Dr. Jones

Economical Adjustable Mouse Platform
San Diego Chiropractic
Pain Relief San Diego Chiropractor