England star Kevin Pietersen believes the Hawk-Eye technology now used in cricket is causing concern for batsman all over the world.
Pietersen has endured several problems against left-arm spin in England's warm-up games ahead of the first Test in Chittagong, but after hitting 99 in first innings of the win, he bounced back to form.
However, he feels umpires are now more inclined to award leg before decisions since Hawk-Eye technology has been added to the game and his peers have to work hard to counter the threat.
He said: "If you look at some of the decisions, I think Hawk-Eye has definitely played a huge role in lbws being given off the front foot.
"So you've got to sort your technique out and make sure you use your bat as the first line of defence.
"Batting has changed. It's no surprise to see that three of the top ranked bowlers in one-day cricket are left-armers (Shakib Al Hasan, Daniel Vettori and Ray Price) and that tells you something - there is work to be done."