The most common factor is lumbar disc problems, from the orthopedic surgery point of view, lumbar disc herniation, lumbar disc bulge, sacroiliac arthritis, sciatica can damage the nerves in the lower limbs, which can lead to a feeling of lower body tightness. 2, lower limb tightness is also related to cerebrovascular disease, in the cerebrovascular damage, such as acute stroke, acute cerebral hemorrhage, acute cerebral embolism, acute cerebral infarction and acute cerebrovascular accident, when the neurons of the lower limbs are touched, the lower limb neuronal function is impaired, 3. When there is an infection in the lower extremities, such as a bacterial, viral or fungal infection in both feet or both lower legs, it will go upwards retrogradely, and then there will be a soft tissue infection around the skin, such as cellulitis. In the case of cellulitis, for example, if the septic bacteria continue to infect the upper body, there will be bouts of tightness and discomfort in the lower body.