When you kick a soccer ball your leg puts kinetic energy in the ball. Also when you kick a soccer ball the ball deforms for an instant. The energy going into the collision is the energy of your foot plus some stored energy in the ball. The energy coming out of is the movement of the ball plus some minuscule heat energy. Due to the deformity in the ball as well as the conservation of energy, the ball actually travels faster than your foot. it is commonly thought in the world of soccer that are taller or larger soccer player will produce a faster shot, this is not the case and it turns out to be the opposite of this theory. The velocity of the ball equals the velocity of the leg multiplied by the fraction of the mass of the leg over the total mass of the leg and the ball, multiplied by (1 + e). e being the coefficient of restitution, which is a constant measure by the seed the ball bounces up compared to the speed it hits the ground with. By the logic of this equation, when a smaller mass is applied, a smaller kicker should be able to kick a soccer ball faster. The kicking of a soccer ball is very complex and may not be as simple as it seems.