Sports and leisure have been necessary to improve our quality of life. Moreover, sports and leisure will also be becoming more essential and important for our life in future. The latest sports have depended more on performance of the hardwares such as equiipments and facilities. Therefore, in order to achieve ever higher performance or improvement of safety and comfort of the hardwares, human dynamics must be taken into the design account. Besides, Human dynamics must be quite important for not only the design of the sports hardwares but also the industrial products requiring highly compatibility with humans. Therefore, Our purposes are to make our leisure or living life more safe and comfortable and to develop a new field of mechanical engineering.