(This is Part 5 of the Repetitive Strain Series)
In the last post I talked about a key behavioral habit that contributes to repetitive strain injury (RSI): poor posture. I walked you through finding skeletal support using the four points of your feet and sit bones so that sitting is easier and more comfortable.
Before I dive into the two remaining behavioral habits that can lead to repetitive strain (excessive effort and lack of awareness), there’s one more aspect of posture I’d like to discuss: the “posture” of your hands and arms.
People often arrange their hands and arms in unnecessarily strenuous positions while using a computer—and with tablets and phones, the situation only gets worse. Unless you have pain, you probably don’t think much about how you’re using your hands and arms. This is the perfect time to nip those hidden strains in the bud before they lead to strain.
Being on a Computer Isn’t Exactly Natural
Sitting using a computer or other device for hours a day is innately unnatural. It doesn’t help that the equipment is often a poor fit for our bodies.
Take standard keyboards for example. While the average shoulder width is 15 inches for women and 18 inches for men, the most-used keys on a keyboard are about 6-8 inches wide, requiring holding your hands quite a bit narrower than your shoulders.
Keyboards (and mice) also require turning your palms face down, the end of your forearm’s mechanical range and a direction that requires muscular effort to maintain. Also, a few of the most commonly-used keys are at the far right and left of the keyboard, asking a lot from your shortest, weakest pinky and ring fingers.
Another example of problematic equipment is the arms on chairs. While the idea of leaning on armrests sounds good, doing so usually means giving up internal skeletal support, putting strain on other parts of yourself, as well as excess pressure on the nerves and blood vessels in your arms. Armrests also restrict movement and can prevent getting as close to the keyboard and mouse as you need to be.
Find Your Personal Comfort Zone
With all these inherent obstacles, it’s vital to spend some time organizing the arrangement of your chair, desk, keyboard and mouse.
Ergonomic guidelines, with all their prescribed angles and distances, can be useful. But you aren’t an average; you’re an individual with a unique body and history. So let’s set guidelines aside for a moment and find your personal comfort zone using the three explorations below. You’ll need a chair, preferably without wheels and not at your computer for now.
Exploration #1: How Close Do I Want My Keyboard and Mouse?
Sit at the front of your chair. Since the first step in arm comfort is finding skeletal support from your pelvis and spine, take a few moments to find your sit bones. (See the last article for how to do this)
1. Hold Your Arms Out
With your arms straight, raise them in front of you as if to type on a keyboard at arm’s length. Observe the amount of muscular work is needed to hold your arms in the air to reach a keyboard at this distance. Lower your arms and rest.
2. Move Your Elbows Forward
With your arms hanging at your sides, bend your elbows 90 degrees (forearms parallel with the floor). Move your elbows a little forward, in front of your torso (your arms will straighten slightly). Listen for any effort in your back, shoulders or arms. If you can’t tell, hold your arms there for 15-30 seconds and notice any places that begin to tire or feel strain.
3. Move Your Elbows Back
Again, bend your elbows so your forearms are parallel to the floor. This time, move your elbows a little backward, behind your torso. Feel which muscles engage now. Lower your arms and rest.
4. Find the Easiest Place
Finally, gently move your elbows a little forward and back, as if they are pendulums swinging from your shoulders. Gradually make the movement smaller looking for where your upper arms and elbows simply hang from your shoulders. Where are your hands now? This is likely the optimum distance at which to put your keyboard and mouse.
The Bottom Line on the Distance of Your Keyboard and Mouse
The further your hands are away from your torso, the more effort you’ll need to hold them up. The weight of your arms is roughly 10% of your total weight. If you weigh 140 pounds, that’s 14 pounds!
Exploration #2: How High Do I Want My Keyboard and Mouse?
Start in the easy position you found at the end of Exploration #1.
1. Hands Higher than Elbows
Raise your hands a little higher than your elbows (elbows hanging more or less below your shoulder joints). How comfortable is this? Keep your hands here for 15-30 seconds or until you are able to sense the effort needed to hold your hands here. Lower your arms and rest.
2. Hands and Elbows the Same Height
Have your hands at the same height as your elbows. Is this more or less comfortable?
3. Hands Lower than Elbows
Now lower your hands a little below the height of your elbows, so your forearms slope down, away from you. Compare the amount of effort with the other two positions. Rest.
4. Find the Easiest Height
Finally, bring your hands to the height that was most comfortable. Play with moving your hands in a small range slightly higher and lower. Zero in on the place that requires the least amount of effort. This is likely the best height for your keyboard and mouse.
The Bottom Line on the Height of Your Keyboard
Standard ergonomic advice is to have the forearms parallel to the floor. I find having the hands lower than the elbows is more comfortable. One way to do this is to have your keyboard on your lap, with or without a lap tray. Play around and see what works best for you. And remember, you don’t have to pick just one place for your keyboard—you can change between different options during your day or week.
Exploration #3: How Can I “Float” My Wrists?
If you’d like, you can sit at your computer for this exploration.
1. Bend Your Wrists Back
Sit at the front of your chair with arms hanging at your sides. Slowly bend your wrists so the backs of your hands start to face the ceiling, then let them hang again. As you repeat this slowly several times, observe the difference in effort between these two positions. Feel how even the smallest bend engages muscles in your forearms. You might even feel some work into your upper arms and shoulders.
2. Notice What You Usually Do with Your Wrists
Next, lightly rest your fingertips on your keyboard (or an imaginary one) at the comfortable distance and height you just found. Look at your wrists. Is your wrist straight or bent? Are your knuckles (i.e. base of your fingers) higher or lower than your wrists? Take a moment to adjust the height of your chair and/or your keyboard so your wrists can be straight.
3. Float Your Wrists Up
Again, place your fingertips on the keyboard. Then imagine a helium balloon tied to each wrist floats it up to the same height as your knuckles. If you set a marble on your wrist, it would roll down the back of your hand to your knuckles (i.e. not stay in a valley at your wrist).
4. Find the Easiest Height for Your Wrists
Now gently raise and lower both wrists a small amount so they go a little higher and lower than your knuckles. Gradually hone in on the height that’s most comfortable, where your wrists are neither collapsed nor so high you feel effort.
5. Adjust Your Keyboard
Finally, look at the angle of your forearms and adjust the angle of your keyboard to match. Most likely your keyboard will need to slope a little away from you (i.e. be lower in the back than in the front).
Bottom Line on the Angle of Your Wrists
Typing/mousing with your wrists bent back requires continuous engagement of your forearm muscles which can irritate tendons and nerves.
Traditional ergonomic advice is to type with your wrists straight. However, I advocate “floating” your wrists as you just did. This minimizes muscular effort in your hands and forearms, reduces strain on tendons and allows space for the nerves through the carpal tunnel at the underside of your wrist.
Unfortunately, most keyboard designs angle the keys toward you, pretty much forcing your wrists to bend back. One simple solution is to put a small book under the front end of your keyboard so it’s at least level or slopes slightly away.
Summary of Posture Tips
Here’s a recap on how to prevent/reduce repetitive strain injury by organizing yourself for maximum support and ease when computing.
Good Support: Use the support from your skeleton. This includes sitting on your sit bones (not your tail bone) and having both feet clearly in contact with the floor.
Easy Shoulders & Arms: Allow your shoulders to rest and let your elbows hang from your shoulders.
Hands Below Elbows: Arrange your arms so your hands are slightly lower than your elbows.
Float Your Wrists: So a marble would roll down to your knuckles.
Adjust Your Set Up: Don’t just make due with an uncomfortable set up. Take the time to adjust the height of your chair and desk to work for your body. Then fine-tune the distance and angle of your keyboard and mouse to your personal comfort zone (usually, closer and lower are better).
Want to feel more at ease and less fatigued after being on a computer? Tune in next time when I’ll focus on how to let go of excess effort and tension when using your computer or digital device.