Lack of strength in the feet may be caused by physiological factors, such as overwork; it may also be caused by a herniated lumbar disc compressing the nerves or brain diseases such as cerebral infarction and cerebral hemorrhage. The most common cause of lack of strength in the feet is damage to the leg and foot muscles, which usually occurs after over-exercise or heavy physical labor, and is usually relieved after rest. As for the pathologic factors leading to the lack of strength in the feet, it may be due to the lumbar intervertebral disc herniation compressing the peripheral nerves, usually accompanied by numbness in the lower limbs. The cause of the disease can be clarified by CT or MRI examination and improved by medication, physical therapy or surgery. For the sudden appearance of foot weakness, it may also be triggered by brain diseases, such as cerebral infarction and cerebral hemorrhage. If the lack of strength in the feet persists without relief, it may also be seen in other causes, the patient should go to the hospital in time to clarify the cause of the disease, and under the guidance of the doctor to carry out targeted treatment.