How to sit the healthiest?

How to sit the healthiest? 1. Don't lean your head and neck forward. 2. The height of the chair should make the knees bend 90 degrees. When your elbow is bent 90 degrees, you can use the keyboard easily. It's best if the chair can have a handle, so that the elbow can rest gently. 4. The hips are also bent about 90 degrees, and the bottom of the chair backrest should be slightly raised to support the lumbar spine. Sitting posture also relates to the fitness of the chair. If the chair is too high, it is necessary to rely on something on the table or the keyboard, and the head must lean forward, so the neck must contribute; If the chair is too low, it will also burden the cervical and lumbar vertebrae. Therefore, the correct sitting posture should be matched with the right tables and chairs. When sitting, the height of the chair should bend your knees 90 degrees, and the position of the keyboard should bend your elbows 90 degrees, so that you can type easily. The body does not need to be stretched or bent excessively, and it is most important to keep the normal curves of cervical vertebra, thoracic vertebra and lumbar vertebra. When looking at the screen or writing, try not to lean forward, but let your eyes look down, but if it is inevitable to lean forward, remember to support with your arms to prevent your muscles from being too tight.