Motion in which all parts of a system move in the same direction at the same speed (e.g. a motorcyclist maintaining a motionless posture on a bike that moves in a straight line). Pure linear motion (also called translation) in which a body moves as a unit with different parts not moving relative to each other, is unusual in sport. Different limb movements are usually necessary to produce movement of the whole body. See also curvilinear motion; rectilinear motion.
Subjects: Sports and Exercise Medicine.