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Turtling (AKA an Interview About the Ergonomics of Notebooks)
Talking to an ergnomics expert about how not to destroy yourself while using a notebook.
June 1, 2009 |
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Over the last few months I've been testing out the new Embody chair from Herman Miller. The folks over there sent me one to try out and offered me access to anyone I wanted to speak to should I be interested in writing about my experience. (Just to clear everything up, they sent me a chair, I was not paid anything and not required to post anything.)
The chair's arrival happened to coincide with a bit of shoulder/neck pain, I'm pretty sure it was mostly from laying on the couch and generally terrible posture while using my laptop. So, I took them up on their access and asked to speak to someone on their ergonomics team not just about the chair, but about how to set up a desk for optimal ergonomics. They put me in touch with Gretchen Gscheidle, who led ergonomics-related research on the Embody. Below are my questions and her answers (with a bit of commentary from me in brackets).
Hope this brings everyone a little less pain in their back, shoulders and neck.
Noah: So lots of people have told me the height of my chair needs to leave my feet flat on the floor, but what about the height of my desk? Where should that be?
Gretchen: There are a couple steps to this set up process.
- Start with your feet flat on the floor, and yourself sitting upright.
- With your upper arm resting at your side, bend your elbow to 90 degrees. Your surface, and in particular your keyboard home row, should be at approximately that height, some advocate a little lower, but no more than an inch. Similarly, some advocate a little higher, but again no more than an inch. Depending on how you're proportioned (lower leg length + heel height, torso length, and upper leg length combined) this measurement for the North American and European population ranges between 22" and 32" off the floor.
Without seeing your particular desk, I'm guessting that the sore neck/ shoulders you describe are a function of you "scrunching" your shoulders, i.e. your surface is too high, which is understandable given that 29" and 30" are "standard" desk heights. Really, it endorses the adjustabile height approach that is part and parcel to systems furniture. If, however, you work at a conventional desk, or say have a filing cabinet under your systems work surface, then you should put your keyboard on a supplemental surface that is at the right height for your body.
Noah: How about the computer monitor? Where should that be?
Gretchen: This is a little bit trickier, because of the effects of corrective vision, like bifocals, that some people require or will likely require as they age and sizes of displays. The rough rules of thumb are:
- The display should be about an outstretched, arm's length (or approximately 24") away from your eyes, and
- The vertical center of the display should be 10-15 degrees below an imaginary horizontal line projecting out from your eyes. Both conditions presume starting again from the upright seated position. [Holy crap, I have never even come close to this (especially with my laptop).]
Noah: How have laptops effected posture and ergonomics? I feel like my laptop leaves me constantly hunched over. [I was probably most interested in this one. It's really a terrible thing when you look around and see people scrunched up in a ball using their computers and it can't be good for our bodies. Laptops seem to encourage this bad behavior as we are always looking down at them.]
Gretchen: First off, I'd encourage you to refer to them as "notebooks"--the folks in the tech industry get a little jittery with the term "laptops." There was at least one lawsuit somewhere down the line where a person fell asleep with a powered-up notebook computer on his bare-skinned lap and suffered some serious burns as a result. The lawsuit came about because of the laptop term. But, I digress.
Notebook computers are a significant wrench in the ergonomic rules of thumb because the display and keyboard connection. For the display to be in the right location for the eyes, the keyboard needs to be in a location that is not ideal for keyboarding. The reverse can also be true: keyboard in the right place, display in the wrong place.
You can certainly chalk up that "hunched over" feel to your use of a notebook, but frankly, we see it in desktop configurations too. Herman Miller Research conducted video observation in a range of office settings with a range of office workers in the early 2000s. There were some notebook users in the study, but the majority were desktop users. Subjects' gross torso postures were measured as being upright or forward--including hunched over--some 75 percent of all time that they were seated at the computer. That is something that really caught the attention of Bill Stumpf and Jeff Weber, our designers, in the early days of development for the Embody chair. One of our regular ergonomics consultants has the theory that "the eyes always win." In other words, we will contort the rest of our bodies into awkward, even unhealthy postures as we work, unknowingly, even if it means allowing our eyes to get in the right spot to see most effectively. We chalk it up as well to the seductiveness of what is on your computer display. The thing is, we're not the only ones who've taken note of these hunched over postures. I have counterparts at HP who call these postures "turtling."
Noah: What's the ideal ergonomic desk setup?
Gretchen: It is as simple as our ergonomic mantra: fit the user, fit the task, allow postural change and movement. So, fitting the user as I've outlined above. Fitting the task is taking into account all that you're doing with your computer--notebook or otherwise--and/or paper-based or other tasks. If you're doing a lot of visually-intensive work, you're going to benefit from a larger display, which almost always implies a wider and/or deeper surface. If you're doing keyboard intensive work, it's a good idea to use a full-size keyboard, rather than the built-in. Similar story with pointing tasks--opt for a mouse if it's intensive use, as opposed to a touch pad or such. If you work with paper, make sure there's sufficient space for that too, and also consider the frequency with which you access paper files or other non-computer reference materials. If it's frequent, keep it in your near reach zone--basically your arms extended and waved in a 3D arc. If it's less frequent, you can keep it farther away from you. Allowing postural change and movement, at the very least, you want to sit in something that allows you to sit upright or reclined--the changes in posture are very healthy. If you're all but tethered to your "workstation"--something that is also height adjustable to a standing posture delivers another degree of freedom.
Noah: Did you think about laptops when designing the Embody?
Gretchen Yes, although I would characterize it more broadly than that, and say that we thought about the pervasiveness of technology--notebook or desktop usage--in some cases multiples of that technology. I would also point out that the Embody chair has evolved from what began as a holistic look at the user/ technology interface or something that we call "the two hemispheres of work." Herman Miller plans to unveil the second half of that equation in June.
Noah: I'd like to turn this post into something that generally outlines best practices for working with laptops for long periods.
Gretchen: What I've discussed here addresses those best practices in terms of a "conventional" setup of user/ chair/ technology/ desk. Recognize that there are a whole slew of other postural opportunities that notebook computers allow. I'm not advocating any of them, but lying face down on the floor, sofa, or bed while "working" on a notebook are all feasible. Herman Miller belongs to a non-profit research organization, the Office Ergonomics Research Committee, that is starting to study such in the hopes of developing some recommendations or best practices for those situations as well.
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