A man sitting for an extended period changes positions both consciously and subconsciously. This study, premised on the transactive relation between man and his environment, analyzed through observation the sitting behaviour of theater audience and train passengers, with the aim of understanding the dynamics of sitting posture. The findings show that the number of times a change of posture took place is affected by attire, condition of neighboring seats, and the differences of spacial features and its location. Moreover, they point out to the existence of multiple basic postures such as those determined by the design standard of the seats, as well as seat types. The result of the analysis with Marcov Chain Model indicates irreducible, non periodic pattern of posture transition. The existence of multiple basic postures was confirmed using the stationary distribution method, while the computation of average time intervals shows short interval for the postural change. This analysis of postural transition provides a fundamental understanding that can be utilized as index for the evaluation of seats.
