Smartphones: The Newest Ergonomic Hazard?

Today, smartphones account for more than 60 percent of all mobile phones sold in the U.S. Increasing speed, better features and more apps mean people spend more time on them than ever before. Should employers expect a rise in repetitive strain injuries?

Using a smartphone or tablet for extensive reading can force users to hold their arms and wrists in awkward positions for long periods of time. In addition, the small screen size often makes users slump over the screen to see it better, causing strain in the muscles of the head, neck and shoulders. And finally, relying on thumbs to type for extended periods can cause “BlackBerry thumb.” In this repetitive strain injury (RSI), overuse and awkward positioning cause the tendons at the base of the thumb to become inflamed.

Our All-Important Thumbs

While it may be an overstatement that our thumbs make us human, they do some pretty remarkable things. The thumb accounts for around 50 to 60 percent of all hand function, including specialized functions (opposition, retroposition, palmar abduction and radial abduction). In simpler terms, thumbs allow us to grip things. Although every state workers’ compensation system has a different way of calculating maximum benefits, most will award much more for the loss of a thumb than the loss of other fingers.

Smartphone users might not realize how much strain they are putting on their thumbs until they start to experience pain. The small size and weight of these devices can mislead a user about the pressure they require, Dolores Langford, a registered physiotherapist and certified hand therapist in West Vancouver, British Columbia, told researchers. “If you’re texting, the pressure at the tip of your thumb is amplified twelve times by the time it gets to the base of your thumb,” she said. This means the basal joint must absorb the shock with every keystroke. (Source: Canadian Medical Association Journal, August 9, 2011, 183(11))

As with other RSIs, BlackBerry thumb can become a chronic condition if not addressed soon enough. At their worst, BlackBerry thumb and other smartphone-related RSIs can cause chronic pain, fatigue and loss of productivity, and may require surgery to correct.

To ensure that your employees’ use of mobile devices means more productivity rather than more injuries, consider conducting trainings on the proper use of smartphones and tablets. Key points to cover include:

1. Use the right tool for the task. Where possible, reserve smartphones and tablets for brief uses while on the go. When reading a lot or sending a lengthy email, for example, using a desktop computer will result in less strain on eyes, neck and hands.

   Workaround: Full-sized external keyboards can let a user input text with significantly less hand and wrist strain than “thumb typing” on a smartphone’s screen.

2. Limit repetitive motions—primarily entering text and information. Small keypads make dialing numbers or inputting email addresses more difficult. Store commonly used numbers in memory. Keeping messages brief will reduce keystrokes and resulting stress.

   Workarounds: Using device shortcuts, such as copying and pasting text and using word prediction and auto completion, can also help reduce keystrokes. Switching from thumb-typing to using a finger or two can also give thumbs a needed break.

3. Mind your posture. Smartphone and tablet users often slump or crouch over a small screen to see it. Many manufacturers now offer tablet stands that will hold a tablet vertically for easier viewing, helping workers avoid straining muscles in the neck and shoulders.
4. Use hands properly. If you must hold a smartphone or tablet while typing, hold it in a vertical position, which decreases thumb reach to push a key. To further reduce strain, type using the pads of fingers versus fingernails and maintain a neutral grip, with straight wrists, to avoid straining the wrist and hand.
5. Bigger is better—to a point. Smartphones have been getting bigger to accommodate larger screens. Compare the newest “phablets”—a morph between a smartphone and a tablet—which have 6-inch screens, to the iPhone 4, which has a 3.5- inch screen. (Screens are measured on the diagonal.) A couple of inches might not sound like much, but the increase makes the virtual keys 25 percent larger than on a standard-sized phone. This could reduce strain on the fingers and hand.

   Larger screens can also reduce eyestrain and can enhance reading comprehension. A 2011 study found that screen size significantly affects comprehension of complex reading materials, because users of small-screened devices see less at any given time and must scroll around the page, which distracts attention and takes more time.

   So is bigger always better? A recent article in The Wall Street Journal (March 26, 2014) points out two downsides to larger smartphones—first, they can be harder to grip. And second, after a certain point, your thumbs can’t swipe across the entire screen. The author cautions readers to test these two important aspects of fit before buying a new smartphone. (You might also want to figure in how much extra space a case will take, particularly if you use a heavy-duty phone case.)

6. Minimize eyestrain. Colored screens are less readable in direct sunlight, so workers who use their smartphone primarily outdoors or in natural light might want a monochrome screen for less eye strain when reading text. Those who use their smartphones indoors or in reduced-light environments will need backlight for optimal reading.

   Also, consider the resolution. The longer the reading time, the higher the resolution you need. If you have a lot of text to read, save it for a laptop or PC.

   Cleaning the screen periodically and using a screen protector can also help reduce eyestrain.

7. Take frequent breaks. For suggestions on exercises that can help smartphone and other electronic device users reduce stress, please see the article on P. 4. For more information on preventing RSIs in your workplace, please contact us.

(Source: Compensating Workers for Permanent Partial Disabilities, by Peter S. Barth. Social Security Bulletin, Vol. 65 No. 4, 2003/2004)