What is the ruling on a ma'mum who lags far behind his imam?

The questioner: What is your view regarding... He was asked about a man who delays or lags behind his imam, lagging behind his imam significantly... he is affected in his state of bowing; he bows and continues to recite, he prostrates and remains standing making du'a' until the end... The ma'mum has four states: first, following his imam; or lagging behind; or matching; or preceding. Preceding is not permissible according to one opinion; matching is disliked; excessive lagging, they said, invalidates the prayer, except for following. There is no following; when the imam finishes saying: Allahu Akbar while prostrating, he begins prostrating... or while bowing; is this correct?

The Shaykh: This is entirely correct, with a distinction between bowing and prostrating. If the imam says Allahu Akbar while bowing, the follower follows him by saying Allahu Akbar and bows with him. However, if the imam says Allahu Akbar while prostrating, he does not follow him, but rather lags behind him until he sees that he has placed his forehead on the ground.