The purpose of this study is to suggest practical direction for physical training by reestablishing value of modern physical training based on view of body and recognition on physical training by Yi Hwang and Yi I, and by interpreting thoughts of Respect(敬) and Sincerity(誠), theory of cultivation of Yi Hwang and Yi I from position of Physical education, originated from thoughts of Neo-Confucianism This study is based on doctrine of i, principle, and gi, material force(理氣論) and theory of mind(心 論) among core thoughts of Yi Hwang and Yi I. Doctrine of i, principle, and gi, material force`` explains all the cosmic phenomena, creation of things, and their systematic relationship through doctrine of ``i`` and ``gi``. ``Theory of mind`` discusses human inner structural system composed of mind, nature, and emotion based on ``doctrine of i, principle, and gi, material force``. Based on ``doctrine of i, principle, and gi, material force`` and ``Theory of mind``, this study established meaning of body and physical training,and investigated practice of Physical education through ``theory of cultivation(修養論) which is a process of creating desirable human image by overcoming and transcending human present appearance. The study results are as follows. Yi Hwang, in his ``theory of cultivation``, suggested ``stay in Respect(居敬) and ``investigation(窮理) as method of practicing R Yi Hwang also let people recognize that the base for reaching Respect is healthy body. He tried to practice mind and body to prevent disease and have clear mind by sports activity in modern sense such as stick-throwing game(投壺), hiking, horse riding etc. and methods to cultivate mind and body like Beobin Jeongjwa(sitting right with silence), Doinbeob(導引法) which follows nature, similar to Yoga of Hwalinsimbang(活人心方), exercise strengthening internal organs, finger pressure etc. To reach Sincerity which is base for true and honest mind, Yi I developed cultivation method of strong resolution, stay in respect, investigation and great endeavor which overcomes limitation of temper and implements by oneself. And he put importance on physical activity as base of such cultivation. Physical activities of Yi I are interpreted largely in two ways. One is that he pursued harmony between mind and body by doing Korean chess, paduk, stick-throwing game, Enjoying nature(遊娛山水), swimming etc. to purify spirit. The other is that he recognized value of physical activity in the purpose of strengthening national defence power-based on spirit of great endeavor, excellent soldiers are cultivated through physical activity of male adults at 16~0 years old with duty of military service. According to thoughts of Yi Hwang and Yi I, thus, body and spirit are in mutual supplementary relationship. So, physical activity was recognized as important base in realizing Respect and Sincerity. Especially, physical training aims to cultivate whole-person with knowledge, virtue, and healthy body by letting desirable social value grow through physical activity. And Physical education should be a ground for important education where desirable values such as mind for cooperation and selflessness as well as sociality can be learned because Physical education has more opportunity of interaction compared to other subjects. But now Physical education is being neglected due to education focused on entrance examination, which led to gradual reduction of opportunity for students to learn such valuable values in school field. As shown in above, Yi Hwang and Yi I recognized that physical activity is base in realizing Respect and Sincerity. At this time, it seems that such recognition of Yi Hwang and Yi I makes reconsider importance and value of Physical education. Accordingly, it is judged that Physical education should play a central role in education for cultivating virtue.