Children suddenly feet dare not land may be due to thigh muscle strain, ankle sprain and other factors. 1. Thigh muscle strain: refers to the muscle in the movement of sharp contraction or excessive pulling caused by the injury, usually due to the movement before the warm-up or activities too intense factors. The performance of the local location of pain, spasm, swelling and so on, causing children suddenly a foot afraid to land. 2. Ankle sprain: refers to more than the normal mobility of the ankle joint, caused by the injury. Generally due to inadvertent slip and fall, excessive exercise and other factors. Clinical manifestations of localized pain, subcutaneous bruising, swelling, etc., resulting in the child suddenly a foot dare not ground. The child suddenly feet do not dare to the ground may also have other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, give targeted treatment or treatment.