"When the Prophet ﷺ bowed he was balanced, he did not make his head higher or lower than his back, and he put his hands on his knees." (Using translation from Nasāʾī 1039)  

«كَانَ النَّبِيُّ ﷺ إِذَا رَكَعَ اعْتَدَلَ فَلَمْ يَصُبَّ رَأْسَهُ وَلَمْ يُقْنِعْهُ وَوُضِعَ يَدَيْهِ عَلَى رُكْبَتَيْهِ»