Muhammad bin Amr bin Ata said: I heard Sayyiduna Abu Humayd al-Sa'idi (may Allah be pleased with him) speaking among a group of ten of the Companions, among whom was Sayyiduna Abu Qatadah (may Allah be pleased with him). He mentioned the complete hadith about the manner of the prayer of the Messenger of Allah (peace and blessings be upon him), and in it, it is also mentioned that he (peace and blessings be upon him) then returned to prostration, then rose from prostration saying "Allahu akbar" (Allah is the Greatest), then folded his leg and sat on it upright, until every bone returned, or (he said) settled, in its place, upright.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2758