Grandma walked into the free experience room. She saw a lot of massage chairs on which some people were already exercising. Grandma sat in the massage chair and told the coach, "my arms are sore and my hands and feet are numb." The coach taught grandma some movements: open the palm of one hand and clench the other into a fist. The two hands clap up. After one stroke, the movements of the two hands will be exchanged, which will be repeated all the time.