Sit up, loosen your belt, take off your coat, put your hands on your waist and rub them up and down until your waist feels hot. This method can warm the kidney and strengthen the waist. There are Mingmen points of Du meridian at the waist, Shenshu, Qihai Shu, Dachang Shu, and the bladder meridian of the foot sun. After rubbing, the whole body feels fever, which has the functions of warming kidney, strengthening waist, relaxing muscles and activating blood.