Because that's Chinese medicine hammering therapy. Flapping therapy is based on the theory of meridians and viscera in traditional Chinese medicine. Traditional Chinese medicine believes that beating the body surface can stimulate the qi of human meridians, and through the conduction of meridians, it can tonify Yang Qi, regulate Yin Qi, promote blood circulation and restore the function of viscera. For some common chronic diseases, tapping the corresponding parts and acupoints for a long time can play a preventive and therapeutic role.