Musannaf Ibn Abi Shayba 3:1808

Abu Bakr narrated to us, he said: Hushaym narrated to us, from al-Mughirah, from Ibrahim; and Abu al-Ashhab, from al-Hasan, that they both said: When a man recites the prostration (verse), he should say the takbir when he raises his head and when he prostrates.