Change in Human Center of Gravity Produced by Change in Direction of Acceleration

The two-dimensional location of the center of gravity of the seated human body was studied on 25 male subjects under conditions of experimentally controlled changes in the angle at which a 1-g acceleration acted upon the completely restrained body. It was found tha t varying the direction of the simulated acceleration vector from 15° through 80°, measured from the torso axis forward, produced: 1) a migration of the group average center of gravity along a curved path of 2.15-in. arc length; and 2) a consistent rotation of the axis of maximum individual variability (supposed optim u m thrust vector) from 10° 53' aft of the torso axis to a maximum forward angle of 90° 16'. Speculation concerning the practical applications of these findings to the design of rocket-powered systems (e.g., escape capsules) is presented.