Leg lift is for stride, and stride is for better exertion of pitching kinetic energy and ball speed (ball speed is not only needed for fastball, but also for curveball, so you can't throw a curveball of 30mph). Each pitcher's pitching mechanism is different, and his pitching coherent action is also different, so the angle of leg lifting is also different.

Pitcher is a player who is responsible for throwing the ball for the attacker to hit in baseball or softball games, and is usually regarded as the soul figure who dominates the outcome of the game. As long as it doesn't violate the rules, the pitcher can pitch in any position. When recording game by game, the number 1 is usually used to indicate the pitcher's defensive position.