Leg before wicket (LBW) is a form of cricket dismissal that the bowler executes on the batter. A brief summary of this form of dismissal would be that the batter’s legs came in the way of the ball that would have gone on to hit the wickets. But there are various factors before the batter is deemed out.
Historically, the leg before wicket has a topic of controversies and a measure of the umpire’s acumen in decision-making. Though technological advancements make it easier for the viewer to perceive the proceedings of a leg before wicket event, back in the day it was purely based on the umpire’s instincts. The hawk-eye technology, edge detector, and hotspot detector are regularly used to refine leg before wicket decisions.
Assume a bowler delivering a ball such that it has hit strike the batter’s pads. The bowler appeals to the umpire for a dismissal. To make a decision, the umpire considers some factors.
The first thing is to check where the ball pitched. The ball must pitch in line of the stumps or on the off-side (the side where the batter’s bat is pointed during his stance at the time of the bowler’s run-up) of the stumps. Secondly, the height at which the ball has bounced while going on to hit the pads is assessed.
Finally, it is checked whether or not the ball touched the bat first before going on to hit the pads. Let us hypothesize that in this case the umpire has given his decision in favor of the batter (not out). If the bowler is not convinced, he can go on to challenge or ask the umpire to review the decision.
It was only after the development of hawk-eye and edge detection technology that reviewing the umpire’s decision was introduced. The on-field umpire consults the third umpire who is present in a room with a monitor displaying the replay of the trajectory of the ball. The third umpire first checks if there is any hint of the ball edging the bat before hitting the pads. If yes, then the original decision stands. But if there is no bat is involved, the umpire proceeds for the hawk-eye.
Hawk-eye displays an animated trajectory of the ball from the bowler’s release till it hit the pads. But the trajectory doesn’t stop here. Hawk-eye further extends this trajectory based on the ball’s movement and makes a calculated prediction of where the ball might carry in case it travelled further towards the stumps. The umpire’s original decision is reverted if the extended trajectory hits the stumps. The batter survives. However, in case the pitch of the ball is outside the line of the leg stump, the decision stands and the batter remain not out.
Hawk-eye hasn’t eliminated the controversies of leg before wicket entirely. In some instances, the ball hits the bails and the inference displayed is ‘umpire’s decision’ which means that the original decision of the umpire stands. When even advanced science finds its own challenges, an avid cricketer head must be updated with the advances on LBW.
