Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:2720[Chain 1] Muḥammad b. ʿAbdullāh al-Ḥāfiẓ And ʾAbū Saʿīd b. Abū ʿAmr > Abū al-ʿAbbās Muḥammad b. Yaʿqūb > al-Rabīʿ b. Sulaymān > Shuʿayb b. al-Layth b. Saʿd from my father [Chain 2] Abū ʿAlī al-Rūdhbārī > Abū Bakr b. Dāsah > Abū Dāwud > Qutaybah > al-Layth > Muḥammad b. ʿAjlān > Sumay a freed slave of Abū Bakr > Abū Ṣāliḥ > Abū Hurayrah ؓ

[Machine] The companions of the Prophet complained to the Prophet about the difficulty of prostrating when they spread apart. He said, "Seek help through cushions." Shu'aib added in his narration, "Ibn 'Ajlan said, that is to place his elbows on his knees when prostrating for a long time and becoming tired."  

البيهقي:٢٧٢٠أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللهِ الْحَافِظُ وَأَبُو سَعِيدِ بْنُ أَبِي عَمْرٍو قَالَا ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ ثنا الرَّبِيعُ بْنُ سُلَيْمَانَ ثنا شُعَيْبُ بْنُ اللَّيْثِ بْنِ سَعْدٍ حَدَّثَنَا أَبِي ح وَأَخْبَرَنَا أَبُو عَلِيٍّ الرُّوذْبَارِيُّ أنبأ أَبُو بَكْرِ بْنُ دَاسَةَ ثنا أَبُو دَاوُدَ ثنا قُتَيْبَةُ ثنا اللَّيْثُ عَنْ مُحَمَّدِ بْنِ عَجْلَانَ عَنْ سُمَيٍّ مَوْلَى أَبِي بَكْرٍ عَنْ أَبِي صَالِحٍ عَنْ أَبِي هُرَيْرَةَ ؓ قَالَ

شَكَا أَصْحَابُ رَسُولِ اللهِ ﷺ إِلَى النَّبِيِّ ﷺ مَشَقَّةَ السُّجُودِ عَلَيْهِمْ إِذَا انْفَرَجُوا فَقَالَ اسْتَعِينُوا بِالرُّكَبِ زَادَ شُعَيْبٌ فِي رِوَايَتِهِ قَالَ ابْنُ عَجْلَانَ وَذَلِكَ أَنْ يَضَعَ مِرْفَقَيْهِ عَلَى رُكْبَتَيْهِ إِذَا طَالَ السُّجُودُ وَأَعْيَا  


See similar narrations below:

Collected by Abū Dāwūd
abudawud:902Qutaybah b. Saʿīd > al-Layth > Ibn ʿAjlān > Suma > Abū Ṣāliḥ > Abū Hurayrah

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).  

أبو داود:٩٠٢حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ حَدَّثَنَا اللَّيْثُ عَنِ ابْنِ عَجْلاَنَ عَنْ سُمَىٍّ عَنْ أَبِي صَالِحٍ عَنْ أَبِي هُرَيْرَةَ قَالَ

اشْتَكَى أَصْحَابُ النَّبِيِّ ﷺ إِلَى النَّبِيِّ ﷺ مَشَقَّةَ السُّجُودِ عَلَيْهِمْ إِذَا انْفَرَجُوا فَقَالَ اسْتَعِينُوا بِالرُّكَبِ