The common causes of lumbar weakness are as follows: First, lumbar strain, due to the presence of injury and strain in the muscles of the lumbar region, resulting in congestion, edema, and inflammatory reaction of the muscle fibers, which can limit the function of the muscles. Patients with lumbar muscle strain will have more severe pain when they are active, and will also limit the force of the muscles. Second, it can be seen in the instability of the lumbar spine, including chronic degeneration caused by lumbar vertebral instability, as well as injury caused by intervertebral body slippage, or degeneration caused by lumbar intervertebral disc protrusion, resulting in lumbar spine instability, which will also cause lumbar weakness when exerting force or exertion. Third, in the body of other diseases or accompanying symptoms, such as calcium deficiency will lead to lumbar weakness, generalized fever or tuberculosis infection will produce systemic toxicity symptoms, will also appear in the case of lumbar weakness.