‘Abdallah b. ‘Umar told that God’s Messenger held race between the horses which had been made lean by training from al-Hafya’ to Thaniyat al-Wada’, a distance of six miles, and he held a race between the horses which had not undergone such training from the thaniya* to the mosque of the B. Zuraiq, a distance of a mile.
* Thaniya is a mountain pass. Thaniyat al-Wada' is a pass overlooking Medina by which people went on the road to Mecca.
(Bukhari and Muslim)