Usama was asked about the pace at which the Messenger of Allah ﷺ travelled during the Farewell Pilgrimage, and I was present. He said, "His pace was a steady trot, and whenever he found an open stretch he would quicken to a faster pace, which is above the steady trot, and I was riding behind him."
حدثنا يحيى بن سعيد حدثنا
سئل أسامة عن سير رسول الله ﷺ في حجة الوداع وأنا شاهد قال كان سيره العنق فإذا وجد فجوة نص والنص فوق العنق وأنا رديفه
Its isnad is sahih. It is found in Bukhari 3/518, no. 1666 (Fath), in the book of Hajj, chapter on traveling when setting off, Muslim 2/936, no. 1286m, Abu Dawud 2/197, no. 1923, Nasai 5/258, and Ibn Majah 2/1004, no. 3017.