TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 DEF

Acceleration of the body in the direction from back to the chest.  2, record 1, English, - back%2Dto%2Dchest%20acceleration

Record number: 1, Textual support number: 1 OBS

Several different terminologies have been used to describe physiological acceleration. Since the terminology may be based either on the action of the accelerating vehicle or the reaction of the passenger, the terms used are often confusing to a reader without prior knowledge of the system of terminology used. Probably the most easily understood system is the eyeballs in, eyeballs out, eyeballs down, eyeballs up, etc., terminology used by test pilots, which refers to the sensations experienced by the person being accelerated. Thus, the acceleration experienced in an aircraft pullout or inside loop is eyeballs down. Note that, in the NASA vehicle (center of gravity displacement) terminology, this is -az acceleration. Some physiological-acceleration terminologies designate accelerations in terms of the equivalent displacement acceleration of the subject as if he were starting from rest. In such terminologies a man standing up or sitting down on the surface of the earth is experiencing 1 g of headward acceleration because of gravity. Other descriptive terms used in this way are footward, forward (the acceleration experienced by a man pressed into the seat back by an accelerating vehicle), rearward, leftward, rightward, spineward, sternumward, and tailward. One terminology based on reaction uses the terms head-to-foot (the acceleration generated by a pullout in an aircraft), chest-to-back, foot-to-head, and back-to-chest.  3, record 1, English, - back%2Dto%2Dchest%20acceleration

Record 1,  Textual support,  French

Record 1,  Textual support,  Spanish