Lumbar pain when bending down, common causes are as follows: 1, due to lumbar degeneration, hyperplasia. With age, the metabolism of bone decreases, bone loss, osteoporosis, lumbar vertebrae ah hyperplasia, at the same time the strength decreases, when bending down due to lumbar degeneration, resulting in lumbar spine instability, which produces the corresponding pain.2, can be seen in the lumbar spine infection, such as lumbar spine of bacterial infection or tuberculosis infection, in the bending down will lead to the localization of the painful symptoms.3, can be seen in the lumbar disc herniation The lumbar intervertebral disc herniation can cause pain in the local area. Due to the herniated intervertebral disc compressing the nerve root, when bending over, it will aggravate the compression, resulting in pain. 4, it can be seen in ankylosing spondylitis, due to the pathological changes of the disease, resulting in bone bridge connection between the spine, when bending over, it will pull and squeeze the local bone, resulting in corresponding pain.