This was an exploratory study on measuring body surface measurement change in motion using a motion capture system. The purpose was to test the reliability of a motion capture system as a new body measurement method, and to investigate body surface measurement changes in motion. Using an optical motion capture system, this study focused on the measurement changes on the back of the body while the subject performed an arm rotation test. The results of this study suggested that the motion capture system can be used as a body measurement method, especially for measuring the body in continuous movement. The results of the body surface measurement change in the arm rotation motion test showed that upper body measurements increased or decreased corresponding to the shoulder joint and scapula movement. The shoulder width (-38.45%), back width (16.08%), and back arc at the armpit (27.69%) exhibited the most change.