The Chair As A Health Hazard: Part 2, The Checklist.
Ergonomic recommendations are a pretty simple to follow and will most definitely help minimize the effects of sitting, but they will likely never eliminate the damage caused by a lifetime of sitting. Most chairs in our homes, offices and daily life fail to meet at least some of the basic standards of what is considered an ergonomic performance.
There’s a guideline which allows you to do a simple assessment of your own workspace’s performance. We’ve curated that list with an easy to follow explanation of each point to help ensure you understand your current set up a bit better.
1. Chair Height.
Chair seats should not be too high. The standard height for an ordinary task chair with a flat seat is 18 inches from the floor, but for half of the population this is ineffective. These chairs suit the mythological “average” sized person which is really just a tall male body type. This means for children, most women and a large percentage of men chairs are too high.
When your chair seat is too high it cuts under the knee, pressing the thigh muscles up from below on the edge of the seat. This forces the muscle tissue to take on a load bearing function…. this is not what the thighs are meant for.
Are you sitting right now? Can you feel pressure under your thighs? If you do, your veins and arteries can’t circulate blood properly.
An easy way to tell if your seat is at the right height is if your heels are touching the ground, resting on the floor or on a foot rest of some sort. If your heels are pulled up your thighs are likely being compressed by the front edge of the seat.
But let’s not forget about chairs that are too low. If your knees are higher than your hip joints your hips will not only be at risk of getting jammed but you will also be reversing the natural forward curve of your lower back, stressing the discs.
Even though the “average” chair is a seemingly safe compromise, multiple sized chairs or adjustable chairs are preferable. In a world filled with chairs that are too tall or too short… be a Goldilocks.
2. The Front Rail.
The front rail of your chair should be curved downward. The reason for this is to eliminate the sharp edge that might cut into the flesh under your knee. This is one of the few rules all ergonomic researchers agree on… but it’s still often a rule that broken in the design world.
3. Depth and Width.
Seats should be about 17 inches deep and 17 inches wide. This suits a diverse range of bodies, mostly because the thigh bone has the lowest standard deviation of any bone in the body (fun fact!). This being said, most chairs don’t have 17 inches of usable seat depth. Often times you’ll see the lumbar support of a chair extend too far forward which doesn’t allow you to use the back few inches of the seat.
4. Weight Distribution.
Your weight should be distributed through your bones not your flesh. When you’re sitting you should be able to feel your sit bones on the seat. Quite simply: flesh is not meant to be load bearing, bones are. This means it’s important to avoid deep padding. You should be able to feel your bones carrying the majority of your weight (60 percent to be exact).
Pro tip: Sit on bare wood and rock on your sit bones from front to back. Memorize that feeling and take it with you when buying a chair.
5. Back Space.
It’s important to have space between the seat and the lower edge of the back of the chair. Without this space the sacrum and pelvis will be pushed forward which ruins the natural curve in the lower spine. If your butt doesn’t have space, you fall into the dreaded C-shaped slumped posture right away.
There you have it!
A very sensible, simple checklist of things to follow that are backed up by ample research done by many different ergonomic researchers. The thing is though…. Most of these rules are very rarely followed by designers. Much of this is due to the fact that the public is uninformed to the science of ergonomics and there isn't much priority placed on proper posture and mindful sitting.
If posture and spine health is a priority for you, you may find it difficult to find a chair that hits all of the points listed above. That's why we are making it our #1 priority to create, design and refine our chairs to check off each of these points... how do you think we're doing??