Computer ergonomics are important because working at a computer for prolonged periods can be harmful to your overall health. By designing a job to allow for good posture, less exertion, fewer motions and better heights and reaches, the workstation becomes more efficient.
Good posture reduces your exposure to work hazards such as working in awkward or uncomfortable postures and using excessive force or high repetition to complete a task.
When working with a computer you have to consider your work station design such as your char, table, keyboard, mouse, computer screen etc.
Proper posture to work on computer
Proper desk chair posture
The chair height must be adjustable
Use armrests
Keep feet flat on the floor or use a footrest
Knees are in line (or slightly lower) with hip
Maintain a straight back with hips placed far back in the chair
Back of the chair should be somewhat reclined at an angle of 100 to 110°
There must be at least 2” of clearance between the back of the knees and front of the seat.
The chair should have a backrest that supports the upper and lower back to maintain the natural curve of the spine.
The chair should have the ability to adjust the seat height, armrest height, backrest reclining angle, and supportive headrest.
It should also have comfortable padding on the back and on the seat (seat is cushioned and is rounded with a “waterfall” front – no sharp edge)
There must be a suitable height in the computer table
Keyboard adjustment ⌨️
Position the keyboard directly front of the user
The keyboard must be placed at or slightly below the elbow level (lower arm falls in line when hands place on the keyboard) so that it would reduce bending of the wrists.
The keyboard feet should not be used if this causes wrists to bend upward. Keyboard feet may be used to maintain a neutral/ straight wrist
Arms should be in near your trunk rather than stretched out in from of you
There should be at least an inch of clearance between the bottom of your work surface and the top of your thighs
Monitor adjustment 🖥️
The monitor should be placed slightly below the subject’s eye level
User should be sitting at least 20 inches (or an arm length) away from the computer screen (viewing distance to your monitor should be at least 20 inches
The screen should be placed directly in front of the user
Center of the screen should at 15° down angle from the eyes
Mouse 🖱️
Place the mouse on the same level and immediately after the keyboard
Position the mouse at your side, so that you don’t have to reach out to use the mouse
Do not elevate or extend the upper arm
Maintain a straight line between the hand and the forearm
Do not use a wrist rest while using the mouse
️ Forearm needs to be free to move so that the wrist would not be strained
Further,
You should sit with relaxed shoulders (not lifted shoulders) when working with the computer
Your head should not bend and not turned towards the left or right
Your trunk should not be turned towards left or right and it should be in a symmetrical position
Prolong use of bad postures while working with the computer, can be lead to repetitive stress injuries that primarily affect the soft tissues, including the nerves, tendons, ligaments, and muscles.
Areas that are more prone to experience repetitive stress injuries are,
Neck
Shoulder
Elbow
Wrist
Hip
Ergonomically poor work stations are associated with musculoskeletal disorders.Poor posture can lead to some disorders in computer users. Such as,
Pain on Back, Neck, and Shoulder
Poor Circulation
Impaired Lung Function
Poor Digestion
Constricted Nerves
Misaligned Spine
A Curvature of the Spine
Headache and Jaw Pain
Sitting for long periods is thought to slow the metabolism, which affects the body's ability to regulate blood sugar, blood pressure and break down body fat. Studies have linked being inactive with being overweight and obese, type 2 diabetes, some types of cancer, and early death. To reduce our risk of ill health from inactivity, we are advised to exercise regularly, at least 150 minutes a week, and reduce sitting time. ergonomics team at Cornell University recommend moving regularly to avoid these negative effects, using the principle of 20/20 - 20 seconds away from the sitting position every 20 minutes. In other words, you should always try to stand/move every 20 to 30 minutes.
Repeating motions such as typing for assembly work without breaks can quickly lead to repetitive stress injuries. Though repetition is not very risky, when combined with other risk factors such as high force and poor posture, repetition takes on increased significance.
Typing or “mousing” on a square edge table where the arm makes contact with the “sharp” edge of the desk may lead to a compression injury at the underside of the arm. Eg; carpal tunnel syndrome due to compression of the median nerve
Dinithi Prasanga
References
https://www.conceptseating.com/how-to-properly-sit-at-a-computer
Gerr F., Monteilh C.P. & Marcus M. 2006, ‘Keyboard use and musculoskeletal outcomes among computer users’, Journal of Occupational Rehabilitation 16(3), 265–277.
Waersted M., Hanvold T.N. & Veiersted K.B., 2010, ‘Computer work and musculoskeletal disorders of the neck and upper extremity: A systematic review’, BMC Musculoskeletal Disorders 11, 79
https://www.nhs.uk/live-well/exercise/why-sitting-too-much-is-bad-for-us/
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