An arm ball is a variant of spin bowling that is used by bowler who specialize in off-spin bowling. Off-spin bowling is one where the ball upon pitching deviates to the right. The trajectory of an off-spin makes it predictable for the batters over a period of time. Thus, off-spinners opt for variations like an arm ball.
The pace of an arm ball is quicker than the conventional off-spin deliveries. Bowlers grip the ball wherein they inculcate a backspin on the ball. Upon releasing the ball, the bowler’s wrist movement is such that they might expect the ball to swing subtly. More often than not, an arm ball is pitched in line of the off stump. This is a line which poses a risk for the batters to be dismissed leg before wicket. The length of the ball is usually such that the ball pitches near the stumps. This is called a full length delivery.
An arm ball is used by the bowlers only after bowling a few off-spinners on consecutive deliveries. Since the arm ball spins minimally, when used against the batter at the right time, it keeps the batter guessing on how and where might the ball deviate upon pitching.
Owing to its minimal spin, the arm ball is named so. When left handed bowlers bowl the arm ball, the ball will deviate towards the batter. The ball will move away from the batter when a right arm bowler pitches the arm ball.
In modern cricket, the arm ball has been used effectively by bowlers like Daniel Vettori, Harbhajan Singh, Graeme Swann and Ranaga Herath.
