The normal shape of the spine is an “S”-shaped curve, which has been formed during our evolution. And this kind of curvature is the state where we have the least stress on all parts of the spine when we can complete our daily behaviors. What we mean by sitting upright is not that the spine should be straight, but that the lumbar spine should not be bent forward. Leaning forward can cause compression on the front of the lumbar spine and strain on the back of the lumbar spine. After a long time, it will cause lesions of blood vessels, nerves, and muscles around the lumbar spine, and then we will feel soreness in the waist.
Pay attention to the correct and comfortable sitting posture when using the computer: “Three bends, two supports, and one gap”
The so-called three bends are:
1.Legs bend.
We need to keep our thighs level when we sit in the computer chair to prevent us from sliding forward or backward while sitting on the chair. Keep your feet on the ground naturally, keeping your calves and thighs bent at about 95 degrees. If this angle is too large, it will reduce the upward support force of the calf on the thigh, thus increasing the pressure on the front of the thigh on the cushion, making the muscles in contact with the front of the thigh and the cushion stress, and affecting the blood flow of the leg; If this angle is too small, it will squeeze the blood vessels on the back of the knee bend, resulting in poor blood flow to the thigh.
2.Waist bend.
The correct sitting posture is that our torso is slightly tilted back so that the thigh and the back are at an angle of 100°-110°. I have already mentioned the dangers of leaning forward, so I won’t mention it here. Maybe you’re asking if it’s possible to stay 90 degrees without leaning forward. But when we sit at 90° between the upper body and the thighs, all the gravity of the upper body will be concentrated on the buttocks. At this time, our spine and coccyx are under the greatest pressure, which will lead to lesions of the tissue in this area for a long time. Leaning back not only does not affect our use of the computer, but also distributes the weight of the upper torso to the back.
3.Elbow bent.
When we use the computer, our arms hang down naturally, open to the sides, and the elbow bend is kept between 80°-100°. Usually, the reason why we can’t maintain this posture is mainly determined by the height of the table and seat. We chose to give up comfortable and healthy posture in order to adapt to the table and chairs.
The so-called two supports are:
1.Neck Support.
When we use the computer correctly, we should control the distance between the screen and the eyes, and keep the line of sight level. The main reason why we usually observe the screen downwards or upwards, but not horizontally, is that the screen is too high or too low. Looking down or up on the screen for a long time can cause fatigue in our cervical spine. The correct way to use the computer should be to widen the distance between the screen and the eyes, and reduce the radiation of the computer to the eyes and brain. This requires us to lean our upper body back while keeping our arms away from the computer. At this time, our cervical vertebrae are also in a backward state. To maintain our eye level, we should bow our heads slightly downward. If the neck is in a suspended state, it will cause soreness in the neck muscles over time. Then we need a headrest to support our neck and head and reduce the pressure on the cervical spine.
2.Arm support
Whether we are typing on the keyboard or sliding the mouse, the arm hangs in the air for a long time, increasing the force on the arm, which will cause shoulder muscle lesions over time. The function of the armrest of the computer chair is to support our forearm and reduce the tension on the shoulder.
The last so-called gap is: keep a finger gap between the back of the knee and the front of the seat cushion to increase the blood flow in the bend of the leg.