Squatting for a long time waist straight up, the main reason to consider with lumbar muscle strain, lumbar spine stability decline and lumbar spine structure changes. 1. Lumbar muscle strain: usually if you often bend over and bear the weight of labor or sedentary standing, it is possible to induce lumbar muscle strain, when muscle strain, easy to form a long time squatting lumbar straight up phenomenon, and even accompanied by pain. 2. Decline in lumbar spine stability: usually if the lack of sports exercise or long time posture, lumbar spine stability problems, squatting for a long time is easy to produce the phenomenon of lumbar straight up, and even cause lumbar injury. 3. Lumbar spine structural changes: when the lumbar spine structural changes, such as lumbar disc herniation or lumbar spinal stenosis, after squatting for a long time, it is easy to cause lumbar pain and nerve root compression symptoms, so that the phenomenon of lumbar straight up. If the symptoms persist for a long time, it is easy to affect the function of the lumbar spine, you can go to the orthopedic consultation, after clarifying the cause of the disease, under the guidance of the doctor targeted treatment, as soon as possible to restore the function of the lumbar spine, to prevent the aggravation of the condition later. Usually pay attention to maintenance in life, such as appropriate strength training of the lumbar and back muscles, do not often stooping and weight-bearing labor.