At the most basic level, elite swing mechanics focus on the body’s loading and unloading of energy in an efficient, ground-up sequence. The ground-up swing sequence takes force generated by the feet pressing into the ground and, because of the tension and stretch created during the load phase, efficiently transfers the force up the body’s kinetic chain — legs, hips, torso, and shoulders.  As the body unloads, the force flows up the kinetic chain, with each link in the chain serving as a force multiplier, increasing the force (rotational velocity) as it passes through each segment until the force is transferred at maximum speed out through the hands and barrel at contact.  As a result, when the lower and upper body load and unload in the correct ground-up order, hitters get massive amounts of bat speed without massive effort.