Lu's Spring and Autumn Annals first advocated fitness, believing that regular exercise can strengthen the body and prolong life. Hua Tuo, a famous doctor in the Eastern Han Dynasty, imitated the movements of tigers, deer, bears, apes and birds, and created the "Five Birds Play" gymnastics as a means for people to exercise and keep fit. Sun Simiao and Wang Zhu, famous doctors in the Tang Dynasty, also advocated that people should exercise regularly and moderately.