The Real Risk of Repetitive Motion Injury

Let’s face it and be up front here. Not only do you not want to annoy your users, you probably don’t want to actually injure them, either. (If you’ve simply annoyed your users, you might know what it’s like to receive e-mail from them, where they threaten injury.)

Now I know we’re computer people and many of us are more likely to perform an exorcism than to actually exercise. But whether you work out daily or only during major holidays on every tenth year, you’re probably familiar with that sore-muscle feeling the day after you work out.

The feeling of sore muscles is actually due to the muscles tearing at a microscopic level. When this happens, with the proper nutrition, your muscles heal themselves and become stronger. The key, however, in addition to proper nutrition, is in allowing time for recovery.

But the one exercise many of us do on a daily basis is type at the computer and use the mouse. While this might not seem like much, if you type and work the mouse for eight hours straight, you’re likely to feel it a bit. My personal problem is that my elbow will often ache from reaching over to the mouse. I fixed this by getting a Logitech trackball instead, but I still have to reach over to the trackball. And sometimes my elbow still hurts, although the trackball has definitely helped a great deal. Other people feel pain in their fingers and hands from all the typing.

And, unfortunately, rarely do we give ourselves a few days off to recover from these aches and pains, which are, in fact, torn muscles, tendons, and ligaments. (Now isn’t that a pleasant thought!)

Note

Right through the middle of your wrist runs a nerve called the median nerve. This nerve is especially susceptible to trauma from using a computer keyboard. Damage to this nerve is known as carpal tunnel syndrome (CTS), which most of us have heard of. CTS is an example of a repetitive motion injury (RMI) or repetitive stress injury (RSI).

What can you do to help prevent repetitive motion injury and carpal tunnel syndrome? Since it would be a serious bummer to think that your software was responsible for somebody’s bodily injury, here are some things that you can do:

• Don’t require overuse of the mouse. In other words, include keyboard shortcuts for everything that might otherwise require the mouse. This includes menu items, controls in a dialog box, buttons in a dialog box, the works. And if the mouse is required, don’t make the user bounce back and forth between using the mouse and the keyboard. For example, if you’re writing a graphics program whereby the user can use the mouse to do drawings, set up the software so that the user can work the keyboard with one hand and the mouse with the other. Make this configurable, and don’t forget about the left-handed people, either, who prefer to put the mouse on the left side of the keyboard.

  But also don’t require that the user constantly click in the upper-right part of the screen, then the lower-left, then the upper-right, and so on. For that matter, a lot of very small mouse movements can be bad as well. Further:

• Allow the user to do most of the keyboard work without bouncing the right hand back and forth between the J-position and the cursor and page keys and numeric keypad.

• Create a macro system, whereby users can program repeated keystrokes and activate the keystrokes with a single keystroke or click of the mouse.

• Design your software such that users can take a break from the keyboard without loss of data. This might seem like a strange request, but there are situations where this could be a factor. (Games come to mind.)

Tip

A lot of people who suffer from RSIs find they’re most comfortable with the Dvorak layout of the keyboard rather than the standard QWERTY style. However, if you’re writing software that responds to the keyboard in any way (as most software does), don’t build in Dvorak capabilities. Instead, Windows allows users to configure their own keyboards. This means that if your program receives the letter j as input, you can be assured the user typed j, regardless of where j is on the keyboard.

The common factor here is minimizing the movements of your users. Don’t force them to go through jumps and dances just to get the task done.

Finally, if you want to learn more about the various repetitive motion and stress injuries, I have found a great place to start is by going to Yahoo! and searching on the phrase “repetitive stress injury.”