Narrated Ahmar ibn Jaz: When the Messenger of Allah ﷺ prostrated himself, he kept his arms far away from his sides so much so that we took pity on him.
Hadith Referenceسنن ابي داود / أبواب تفريع استفتاح الصلاة / 900
Hadith Gradingالألبانی:حسن صحيح | زبیر علی زئی:إسناده حسن, أخرجه ابن ماجه (886 وسنده حسن)
Hadith Takhrij« سنن ابن ماجہ/إقامة الصلاة 19 (880)، (تحفة الأشراف: 80)، وقد أخرجہ: مسند احمد (5/30، 4/342، 5/31) (حسن صحیح) »
900. Commentary: That is, he (sallallahu alayhi wa sallam) would keep his arms well away from his sides, to such an extent that those who saw him would feel compassion, thinking that he was enduring great hardship. However, this posture is not possible in congregation or in the prayer row. Nevertheless, if due to old age or illness someone is unable to do so, then there is concession for him to perform prostration (sujud) in whatever manner he is able.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 900