Lower back and leg pain and weakness may be caused by cold, overwork or exercise, lumbar spine disease and other reasons. 1. Cold: prolonged exposure to humidity and frequent exposure to cold can easily lead to lumbago and leg pain and weakness. 2. Excessive exertion or exercise: Excessive exertion, over-exercise, and improper exercise may cause damage to the muscles of the waist and legs, resulting in lumbar and leg pain and weakness. 3. Lumbar spine disease: lumbar spine disease such as lumbar disc herniation affects the lumbar region, causing obvious pain in the lumbar region, and nerve compression is serious, leading to the emergence of lower limb soreness and weakness. Rheumatoid arthritis, bone degeneration in middle-aged and old people and other diseases can also lead to the emergence of lumbago and leg pain and weakness. It is recommended that patients go to the hospital in a timely manner, under the guidance of the doctor to clarify the diagnosis and treatment.