Everyone knows it’s more convenient to sit than to stand and it’s even better to lie down than it is to sit. If we take a look at this situation from a mechanical point of view, the best positions are standing and lying. That’s why, when a person suffers from back disease or a spine trauma, they are forbidden to sit for extended periods or at least sedentary loading is somewhat restricted. In the modern world, sitting is the most widespread position for working, studying, and resting. Unfortunately, neither at home nor in school, are children taught to sit correctly.
In the picture, you see the perfect position for working at a desk or table. You can see that the workspace includes not only a chair, but also a table, a computer, and other furniture. Despite the fact that this posture looks easy to accomplish, we still most often slump ourselves into the fetal position while working. Our back becomes crooked instead of leaning on the back of our chair, and the entire weight of our body is then being supported by our arms, which are leaning on our desk. In this position, our neck becomes curved like an “S.”
This posture was described in the section on the work of neck levers. While in this position, the spine loses its lumbar lordosis: it turns into kyphosis. And in combination with a curved neck, this person resembles an ugly dwarf. In previous times, this posture was created by closing a child in a box for several years. As the child grew, the skeleton was forced against the sides of the box and became totally deformed. As horrible as it sounds, we often resemble these poor people!
Another position you’re familiar with is sitting with your legs crossed, one up over the other. In this position, the overloading on the neck and lower back is enormous. This causes diseases and pain in both the low back and the neck.
One chapter of this book is dedicated to maintaining correct posture during work. Here I would only like to say that there are additional devices to help with this. They primarily concern the organization of your working space and are studied by the science of ergonomics. This science says, for example, the chair you sit on while working must be adjustable. This is so the chair legs can be set at such a height that your feet can freely and confidently rest on the floor. This is especially important for a child, whose feet should never hang from a chair. When the feet are dangling, the body has only one supporting point, the buttocks, and that’s why the entire posture will become wrong. A base of support under the feet maintains the body in a straight position. In order to do this, you have to put some support under your child’s feet if the chair is too high. And, of course, it is inadmissible to sit on a chair with legs crossed because, in this case, instead of two supporting points you have just one of them. Besides, in this position it’s very hard to maintain the necessary lumbar curve.
The following principle of sitting correctly in a chair is the full use of the chair back and seat. If a chair is too big, then a child will not be able to reach its back. In this case, place the child in a chair that is adjustable, with the option of changing the size of the seat and the position of the back. When a chair is used correctly, the buttocks must be totally situated on the seat and the person’s back must reach the back of the chair back. It is also important that the chair back repeats the lower back curves. Unfortunately, most chair backs are straight. That’s why, to support your low back, it’s necessary to put special rollers behind it.
Some office chairs have wheels. These are convenient for transferring a chair from one room to another, but extremely harmful for posture. To roll away from your desk or table, you have to lean forward and this always results in bad posture. That’s why a chair meant for a child must not have wheels.
The table or desk itself is also a very important part of the workspace. The table must be of such a height that your elbows can lie on top of it freely and without tension. The distance from the table to your face should be approximately equal to the length of your forearm and your hand.
It’s critical while working at the computer that your shoulders and hands feel no tension. If your table is higher than necessary, working on a keyboard will require you to bend your hands at the wrist joint unnaturally. This position puts tension on hand tissues and can cause a tunnel syndrome. This is a disease that occurs when the median nerve in the carpal canal is pressed and fingers become numb and painful.
Another consequence of a desk that is too high is that it makes you want to raise your shoulders. Your head gradually becomes drawn down. Of course, this position is incorrect and results in pain. Some tables have pullout boards for the keyboard. These are usually situated at the height of an elderly person. They create more room on the desk and it’s convenient to pull out the keyboard when you need it. On the other hand, a board pulled out from under the table makes the distance from your eyes to a monitor farther. This isn’t always perfect, so then you have to move the monitor closer to the edge of the table. It’s important to set the monitor so that its upper edge is at eye-level. This position is the best for your vision and you don’t have to bend your back and neck to bring your head closer to the computer screen.
- Sedentary work creates tremendous load on both the cervical and lumbar spine.
- The ergonomic principles of workspace organization help maintain correct posture.