The Companions of the Prophet ﷺ complained to the Prophet ﷺ about the hardship when they kept their forearms far away from their sides while prostrating. He said: Take help with the elbows (by spreading them on the ground and sticking them to the sides). (Using translation from Abū Dāʾūd 902)
شَكَا أَصْحَابُ النَّبِيِّ ﷺ إِلَيْهِ مَشَقَّةَ السُّجُودِ عَلَيْهِمْ إِذَا تَفَرَّجُوا فَقَالَ اسْتَعِينُوا بِالرُّكَبِ