acceleration: increase in the rate of speed of something.

bi-lateral: having or relating to two sides; affecting both sides.

butt: the flat end of the bottom or base of the racket handle.

hitting zone: the distance the racket travels with the face of the racket facing the target.

impression: the measure of views of any piece of media performance; any interaction a viewer has with a piece of content.

one-sided-ness: 1. on having or involving only one side 2. larger or more developed on one side 3. favoring one side.

scissor kick: a kick in which the legs make a sharp snapping movement like the blades of a pair of scissors.unit-turn: upper-body rotation with both hands on the racquet.