Weakness in the lower back should be considered to be related to fatigue, malnutrition, lumbar disc herniation, lumbar muscle strain, and so on. 1. Exhaustion or malnutrition: when long-term malnutrition, long-term bed-ridden will cause physical weakness, thus feeling weak and achy waist. Excessive fatigue can also lead to lumbar weakness, such as sudden strenuous exercise or heavy physical labor. 2. Lumbar disc herniation: Lumbar disc herniation may compress the lumbar nerve root, so it is easy to cause lumbar pain and weakness. The root cause of lumbar disc herniation is the aging of the intervertebral discs, which leads to degenerative changes. The main treatment is physical therapy, medication or surgery to relieve the symptoms by relieving the compression on the nerve roots. 3. Lumbar muscle strain: Lumbar muscle strain can also lead to lumbar weakness, if long-term stooping work is easy to damage the lumbar muscles, which leads to lumbar muscle strain. The treatment for lumbar muscle strain is comprehensive treatment, need more bed rest, if there is pain, you can use medication under the guidance of the doctor to help analgesic and anti-inflammatory, such as ibuprofen, meloxicam and so on. There are many other causes of lumbar weakness, it is recommended to consult a doctor in time, follow the doctor’s instructions for treatment, and avoid blindly using drugs on their own.