Though many theories concerning life-long sport have been proposed, the question of the conceptual structure and theory of life-long sport have still been remained open. In the discipline of philosophy of sport, Ohashi presents a structural clarification of the concept of life-long sport. However, the question remains as to what is a life-long sport. The purpose of this study is, therefore, to show the concept of life-long sport and propose a model for discussion. The procedure of this study is as follows: 1. The author examines the meaning of life-long sport in terms of both political and social points. 2. The author examines critically a life-span developmental theory from the viewpoint of the body and its life cycles. 3. The author considers the concept of life-long sport and a theory for life-long sport that discusses a life-long sport itself. The consequences of discussion are summarized as below:
1. Even if, one says, that life-long sport is socially important, the question of what the values are among individuals still remains.
2. E. Erikson's life-span developmental theory lacks the body as a factor.
3. Life-span developmental theory is seen as the idea of life-long sport. Such a hypothesis makes possible that one can interpret a structure of life-long sport threefold, idea, principle and practice. The principle of life-long sport should not be constituted by the life-span developmental theory, but by the results of physical education or sport science because the body is a very important factor to be considered.