The health problems associated with prolonged working at computer workstations have been much publicized. A specific legislation entitled Occupational Safety and Health (Display Screen Equipment) Regulation was enacted in 2002 for addressing the corresponding health risks. You can learn more about the detailed requirements from this webpage:
www.ab.ust.hk/hseo/dse/Default.htm

Standard guidelines have been recommended by medical and health experts on how to set up an ergonomically sound computer workstation and how to adopt appropriate healthy work practices at the computer workstation. A webpage (http://www.ab.ust.hk/hseo/ergo/index.htm) had been developed by HSEO some years ago containing information based on these guidelines and recognized good practices. These guidelines must always be observed and followed to prevent us from having painful injuries that can be caused by improper work practices.

However, as mobile technology becomes more developed and its application becomes more widespread nowadays, many of us are spending more and more time with mobile and handheld devices. This has created additional ergonomic challenges to many people and makes the issue more complicated because the ergonomic problems being encountered nowadays cannot simply be attributed to working with desktop computers alone. Therefore, in addition to reminding readers to observe the recommended guidelines and adopt proper work practices in using traditional desktop computers, this article also aims to provide readers further safety and health guidelines specific to the use of mobile and handheld computing devices which may or may not be used at work.

Notebook computers provide a convenient and portable platform for users who need to work on the move. With the continuous improvement in computing power and significant reduction in price, notebook computers have now become the primary computing device for many people, especially for students. Unfortunately, the integrated design (keyboard, mouse and screen) of notebooks has made them far less flexible and adjustable in providing a sound ergonomic setup for long term use. Typing on a compact-sized keyboard (e.g. with a small size notebook) would also create additional stress to the fingers and wrists of the users. Therefore, notebook computers should not be regarded as an ideal substitute for desktop computers. When a notebook computer is used on a long term basis like a desktop computer, it should be set up like a desktop computer following the same safety and health guidelines (refer to the webpage mentioned above). To do that you need to attach an external keyboard and mouse to the notebook for making the necessary adjustments. You may also need to raise the notebook computer (by appropriate means) so that the level of the screen is at the right level. If the screen of the notebook is too small, you should also consider attaching a separate monitor of a larger screen size.

Special precautions must be taken when notebook computers are being used in casual manner. First of all, avoid settings such as lying on a bed or sitting on a very soft crouch. Maintain a sitting position on a firm chair as far as possible. The notebook computer should be placed so that you can type on the keyboard without creating too much stress on your shoulders, forearms, wrists and fingers. Be aware of your postures constantly and refrain from hunching over (bending your back and protruding your neck and head).

Making appropriate body adjustments and taking breaks (and appropriate stretching exercises) at frequent intervals are especially necessary for working with a notebook computer. The time duration between breaks varies depending on the health conditions of individuals and the particular work setting (but should not exceed 30 minutes for 1 to 2 minutes’ break). Be alert of the warning signals given by the stresses developed in your body (especially in the back, neck, shoulders, forearms, wrists, hands and fingers) and take a break whenever you feel necessary.

If you have to use your notebook occasionally in situations which are far less favorable, such as sitting on a couch with the notebook resting on your lap, you should:

•  Sit with your back upright (or in a slightly reclined posture) supported by a firm cushion or other suitable object at your back.
• Make suitable adjustments and pay attention to your posture to prevent hunching over the notebook and overstressing your neck and back.
• Elevate your notebook to a suitable height by placing suitable firm object (such as a 2- to 3-inch binder) on your lap so that you can type on the keyboard without too much overstressing your shoulders, forearms and wrists.
• Adjust the angle of the screen so that you can see the display on it comfortably with your head maintained in the natural position.
• Take frequent breaks and perform appropriate stretching exercises.

The health (musculoskeletal) problems caused by using tablets and smartphones are obvious. Because these are normally handheld devices, they are usually positioned at a level way below the eyesight of the user. As such, users need to look down on the screen, causing their necks to bend and backs to hunch over. People tend to forget about their posture when they become engrossed in their devices. When users are stuck in such an unnatural posture for prolonged periods, it can lead to tightness of the shoulders, soreness in the neck and even headache. In serious cases, it can lead to inflammation of the neck muscles, ligaments and nerves, as well as arthritic damage. Soreness may also develop in the hands and arms caused by the need for holding up the device (especially for heavier tablets) for prolonged periods.

The causes for such problems are more difficult to control as the use of these devices is rather personal and usually outside the work setting. It requires the awareness of users and their understanding of and consciously adopting some basic ergonomic principles, such as the following:

• Be aware of your posture and the warning message your body is sending to you.
• Take frequent breaks and adjust your posture whenever you feel any muscular pain and discomfort, e.g. looking up and bringing your neck back into a natural position where the least amount of stress is placed on the muscles.
• Holding your mobile device higher up to your eyes can help maintaining your head at a natural position and reducing the stress in your neck. However, you cannot hold your device high up for too long before soreness develops in your hand and arm. Just take a break whenever you feel any discomfort.
• When you need to read on your mobile device for a long period of time, you really should do it in a more appropriate setting, such as placing your device on a suitable stand inclined at an angle optimum to your eyesight.
• Avoid placing your tablet on your lap (even with a stand) when typing or just reading or watching movie. This is the worst way to use your tablet because it will cause an excessive bending of your neck, creating much strain on your neck and shoulders. The best way is to prop up your tablet on a suitably designed stand on a table or other suitable surface that can raise the tablet to an appropriate level so that your head can remain at the natural position.

As mentioned above, tablets are more comfortable to read at a steeper angle near to vertical (around 45 to 60 degrees). Typing on touch screen with such steep angles can cause the wrist to bend back excessively, creating much more pressure on the muscles and nerves of the wrists and forearms.

Another problem unique to touch screen keyboard is the lack of tactile feedback. While mechanical keys would move and offer resistance during typing, virtual keys on touch screen do not react when being pressed (except for some clicking sound). As a result, users tend to strike the virtual keys with a larger force, putting more strain on the fingers, wrist and forearm.

Typing (or texting) on a smartphone may be a bit different from typing on a tablet because it usually only involves one or two fingers (mostly the thumb). “Blackberry thumbs” is a term coined for a form of repetitive strain injury caused by the excessive use of the thumbs to press buttons on smartphones with symptoms of throbbing pain in the thumbs or sometimes other fingers and in the wrist.

The golden rule for preventing such injuries is to limit the duration and frequency of typing on these devices and to take frequent breaks, although there are some other measures you may take to minimize the risk of injury, such as:

• Draft briefer messages on mobile devices
• Reduce keystrokes with text short cuts and word recognition feature, or use voice input if feasible.
• Type on separate keyboard while placing the tablet on a stand when more extensive typing is necessary.

Again, the golden rule here is to take frequent rests for your eyes. Remember to blink (to wet you eyes) and look at distant objects more often. Of course it would help by properly adjusting the brightness and font size of your mobile device.

Further Reference: Health talk on "Neck & Back Pain and Office Ergonomics"

http://video.ust.hk/Watch.aspx?Video=F44872CD0D1C1AC1