Sunan an-Nasa'i, Hadith 2940 ⓘ
It was narrated from Nafi that: Abdulla bin Umar used to walk rapidly for three (rounds), and walk for four, and he said that the Messenger of Allah used to do that.
أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ عُبَيْدِ اللَّهِ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَرْمُلُ الثَّلاَثَ وَيَمْشِي الأَرْبَعَ وَيَزْعُمُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَفْعَلُ ذَلِكَ .
also referenced under: Book 24, Hadith 0 (In-Book) & Volume 3, Book 24, Hadith 2943 (DarusSalam)