Nearly all batting mechanics, whether taught by coaches or described in books and videotapes, are based on "linear mechanics." By linear, I refer to the concept that bat speed is derived from the batters forward weight shift and extension of his hands. Batters are instructed to direct their energies in a fairly straight line back in the direction of the pitcher. Liner mechanics has promoted terms like: "Step into the ball," "Transfer your weight from back to front," "Keep your shoulder in there," "Pop your hips at contact," "Throw the hands or heel of the bat at the ball," and so on.