Ergonomists describe ergonomics as the study of human capabilities in relationship to work demands.
The word ergonomics is derived from the Greek words “ergon”, meaning work, and “nomoi”, meaning natural flaws. The purpose of this article is to stress the importance of safe workplace ergonomics for those who spend long periods of time using a computer.
Safe ergonomics while using a computer is largely dependent upon sitting posture. Sitting with good posture reduces strain on muscles, ligaments, tendons, joints and other soft tissues. With the increased use of computers, more people find themselves in careers which require them to sit for long periods of time. Prolonged sitting with poor posture increases the potential for physical injury caused by repetitive or prolonged strain. Such injuries may include: carpal tunnel syndrome, medial or lateral elbow tendonitis, rotator cuff tendonitis, neck muscle strain, and low back disc strain.
The following are guidelines for creating a safe computer work station.
- Placed just above the lap with elbows at an “open angle” of 90 degrees or more; keyboard shelf installed below the desk may be useful
- Shoulders relaxed and not raised, with elbows positioned comfortably at the sides
- Wrists in a neutral level position, not bent up or down, or angled sideways; tilt the back edge of the keyboard downwards to achieve this if necessary
- Arm and wrist rests should be used for resting only, and is to be avoided while typing
- Position the body over the area of the keyboard most often used
- Broad chested people may consider using a split keyboard to accommodate their body types
- Placed close to the keyboard on a level plane
- Maintain the wrist in a straight or neutral position
- Mouse should fit comfortably in the hand
- Use a gentle touch
- Use whole arm movements to move the mouse
- Positioned directly in front of you
- Adjust height so that the eyes are level with a position 2-3″ below the top of the monitor
- Sit approximately arm’s length away from the screen to avoid neck and eye strain
- Avoid glare on the screen from windows or ambient light which also may lead to eye strain
- Use computer accessories such as a document holder, headset or speaker phone to avoid unnecessary neck strain
- Sit back as far as possible in the chair with your back against the lumbar support, and with feet flat on the floor or on a footstool; there should be several inches between the backs of your knees and the front edge of the seat pan
- Hip and knees should be at an angle slightly greater than 90 degrees
- Avoid slouching or placing your head and neck in a forward head posture
For individuals who work for prolonged periods of time on a computer, there are some healthy work habits that can be easily maintained to avoid excessive strain on the body, helping prevent repetitive strain injuries.
Changing positions by getting up out of the chair every 15- 20 minutes to answer the phone, retrieve a file or walk around the desk is an easy way to change positions. Recline backwards periodically in your chair to relieve lower back strain. Take regular stretch breaks every 1-2 hours, or more often if possible, to move the joints through normal ranges of motion and stretch tight muscles. This will allow increased blood flow into muscles that are maintaining static postures. Place everything you frequently require within arm’s length on your work surface. Using a light touch on the keyboard and on the mouse will help to avoid placing excessive strain on the hands and wrists.
The following are some stretches that can be easily carried out at the office or at home. These stretches should be done gently and only to the point of stretch, not pain. If you experience pain or discomfort, either decrease the intensity of the stretch, or discontinue the exercise and consult with a physiotherapist.
Prolonged computer work with poor ergonomics often leads to repetitive strain injuries. Seeking advice early from a health care professional such as a medical doctor, physiotherapist or massage therapist is important to prevent symptoms from becoming severe or chronic.
The best way to prevent injuries is to adopt a good sitting posture and optimal work ergonomics. An active lifestyle away from the computer is also important for general health and well-being. Toronto SEMI offers a range of health professionals experienced in the assessment and treatment of various injuries related to computer work and active lifestyles.
Contact SEMI today at 1-855-572-9177 to learn more about our available treatment options.
Martina Kus BSc. P.T.
Printed: April 2005
Copyright ©2005 SEMI