Twenty20 cricket is played over 20 overs according to normal limited-over rules, the one exception being the rule for "timed out", where the time by which an incoming batsman must be at the crease ready to receive his first ball is reduced to 90 seconds after the outgoing batsman has been dismissed. This amendment to the rules helps speed up the game. Additionally, boundary ropes tend to be shorter in Twenty20 cricket than for normal limited over games.