1, head down more, head up less Our head weighs about 17-18 pounds, and this is supported by the bones and neck, and there are many muscles on both sides of the cervical spine to support the head and silently contribute, there are trapezius, head semi-spinous muscle, head pinch muscle, cervical pinch ridge, sternocleidomastoid muscle, head long muscle, head oblique muscle, head straight muscle, head after the large straight muscle … …If you keep a posture does not move, such as long-term head down, the back of the muscle is loose, over time lost elasticity, the head is easy to droop forward, and even affect the ligaments, joint capsule, small joints, resulting in a series of cervical spondylosis symptoms. 2, stilted legs The second leg refers to the frame leg and sit, stilted a foot. When sitting with legs crossed, it is easy to hunch over, causing uneven pressure distribution between the lumbar and thoracic vertebrae, which in the long run is bound to compress the spinal nerves and cause lower back pain. So people often say that “sitting has a sitting” or have some truth, change the bad habits of crossed legs. 3, sitting for a long time after the evolution of people from crawling into upright, cervical, thoracic, lumbar vertebrae under the action of gravity, vertical extrusion, causing a series of changes. Coupled with labor, frequent bending or sedentary, it is easy to cause chronic injury, spinal stenosis or disc herniation, resulting in cervical spondylosis, dizziness and headache, back pain, arm pain, and even cause unstable walking. In the case of non-weight-bearing, lying down, the weight of the lumbar spine is about 25% of the body weight; lying on the side, the pressure on the lumbar spine is 75% of the body weight; sitting, the pressure on the lumbar spine is 140% of the body weight. In the case of weight-bearing, the pressure on the lumbar spine is even greater. Therefore, it is recommended that we do not sit for a long time, especially not on a flimsy sofa. Because when sitting on the sofa, the body will sink, the muscles are prone to long-term tension, although sitting very comfortable at the moment, a long time will lead to a series of major problems. In addition, no matter how busy, it is best to lie down at noon to rest for 15 minutes, especially for people over 50 years old, more appropriate lunch break. If there is a problem with the waist, sitting, the most comfortable angle is the lumbar vertebrae back 120 ° -140 °, if necessary, you can cushion a cushion behind the waist. 4, long-term shoulder backpack There is a rotator cuff at the shoulder, and its most common injury is the supraspinatus muscle. For example, when backpacking, the supraspinatus muscle is pressed by the bag strap, the muscle will be ischemic over time, the shoulder is sore, and over time, the supraspinatus muscle is worn, which is very detrimental to the shoulder joint. Compared to a shoulder bag, a shoulder bag is better, or a bag slung over the body. Try to reduce the weight of the backpack and reduce the pressure on the body.