It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him): "When the Prophet (peace and blessings be upon him) had offered the Fajr prayer during a journey, he would walk (for a while)."
No one narrated this hadith from Yahya bin Sa'id (may Allah have mercy on him) except Sulayman bin Bilal (may Allah have mercy on him), none from Sulayman (may Allah have mercy on him) except Ibn al-Mubarak (may Allah have mercy on him), and none from Ibn al-Mubarak (may Allah have mercy on him) except Muhammad bin A'yan (may Allah have mercy on him), while Muhammad bin Abdullah bin Quhzadh (may Allah have mercy on him) is alone in narrating it.
Hadith Referenceالمعجم الأوسط / باب الميم / 6951
Hadith Takhrij«أخرجه الضياء المقدسي فى «الأحاديث المختارة» برقم: 2724، 2725، والبيهقي فى «السنن الكبرى» برقم: 10447»