How to Measure the Speed of Cricket Delivery

Since the mayhem Harold Larwood caused in the 1934 England versus Australia "Bodyline" series, cricket fans have been fascinated by how fast a fast bowler can bowl. A bowler bowls to a batsman facing him 22 yards away. At the point of release, the ball travels from the height of the bowler's arm to the ground where it bounces. Aerodynamic drag slows it down and when it bounces it slows down some more. By the time it reaches the batsman, ball speed has dropped by 10 percent. Measurements can be taken for average speed and for actual speed.

Instructions

    • 1

      Take a stop watch and stand in the position referred to as "behind the bowler's arm," at the bowling end. This means at a point directly in line with the bowler and the batsman. If you stand sideways on to the wicket for a fast bowler's delivery, you will not see the ball. When the bowler releases the ball, start your stopwatch. When the batsman hits the ball, stop the stopwatch. Again, due to the speed of a fast bowler, you will stop the stopwatch on hearing the sound of the ball striking the bat.

    • 2
      The ball reaches the batsman.

      Do this for several balls in a row to even out the variable of your own reaction time in starting and stopping the stopwatch. Calculate the average time of the delivery by dividing the total time on your stopwatch by the number of deliveries bowled. Divide 45 by your answer to get your average delivery time in miles per hour. The 100 mph mark, allegedly reached by Australia's Jeff Thomson and Pakistan's Shaoib Akhtar, takes 0.45 seconds. That is why it is important to rule out the variable of your own reaction time.

    • 3

      Give the bowler one of the new "speedometer" balls. These are the official size, shape and weight of a standard cricket ball but have a small electronic chip in them. The chip measures speed by measuring the time the ball is released from the bowler's hand to when it hits something, normally the batsman's bat. The speed is then shown on an LCD readout on the ball. This should show the average speed of the cricket delivery.

    • 4
      A standard cricket ball with a seam

      Set up a Sports speed radar gun on a tripod behind the bowler's arm. These guns use the Doppler effect to detect the ball speed going directly toward the speed gun at the point the ball leaves the bowler's hand. This is the fastest point in a delivery. Re-set the speed gun to measure ball speed when it reaches the batsman's bat. This is the slowest point. By summing both speeds and dividing by two you will be able to determine the average ball speed for the delivery.

    • 5

      Compare the result using the Sports speed gun with that of the speedometer ball and your own calculations for speed using the stopwatch. Each ball will be unique. The exact speed of a cricket delivery makes no difference on how a game of cricket is played. What is important for cricketing reasons, is whether the ball bowled is slower or faster than the normal pace of the bowler or the delivery that came before it.