When does the one praying say the takbir when he begins the sujud?

The questioner : How is it in the ruku'? Does he say the takbir when his knees reach the ground?

The Shaykh : No, no, ruku' is not sujud.

The questioner : For the ruku', O Shaykh. For the ruku'? For the sujud. For the sujud, yes.

The Shaykh : In the sujud, when he begins to lower himself, he says the takbir. If, for example, he fears that the takbir will end before he reaches the sujud, let him delay the beginning of the takbir until he knows that he will finish the takbir when he reaches the sujud, so that the ma'mum does not precede him.

The questioner : In the middle of the movement now.

The Shaykh : This is in the middle of the transition. If his transition becomes slow and he fears that if he says the takbir when he begins to move, he will finish the takbir before reaching the sujud, may Allah have mercy on you, we tell him: wait until the amount of the takbir remains for you, then say the takbir.