Thigh root joint pain is considered to be caused by muscle injury, femoral head necrosis and lumbar disc herniation. 1. Muscle injury: When doing gymnastics and yoga, the adductor muscle of the thigh will be stretched when the thighs are often over-expanded bilaterally. When the adductor muscle stretches beyond its tolerance limit, it will produce muscle fiber breakage or muscle injury, resulting in thigh root joint pain. 2. Necrosis of the femoral head: As part of the thigh muscle attachment point is close to the joint capsule of the femoral head, necrosis and ischemia of the femoral head as well as the relaxation of the joint capsule will pull the muscle and cause pain. Necrosis of the femoral head will also stimulate the peripheral nerves, causing pain at the thigh root joint. 3. Lumbar disc herniation: When the lumbar disc herniation is serious, it will compress the nerves and cause thigh root joint pain. Patients with symptoms of thigh root joint pain should go to the hospital in time, according to the doctor’s judgment to carry out relevant examinations, so as to clarify the diagnosis.