Bowling, in cricket, is the action of propelling the ball toward the wicket defended by a batter. A player skilled at bowling is called a bowler; a bowler who is also a competent batter is known as an all-rounder. Bowling the ball is distinguished from throwing the ball by a strictly specified biomechanical definition, which restricts the angle of extension of the elbow. A single act of bowling the ball towards the batsman is called a ball or a delivery. Bowlers bowl deliveries in sets of six, called an over. Once a bowler has bowled an over, a teammate will bowl an over from the other end of the pitch. The Laws of Cricket govern how a ball must be bowled. If a ball is bowled illegally, an umpire will rule it a no-ball. If a ball is bowled too wide of the striker for the batsman to be able