Abu Salamah bin Abd al-Rahman said that Sayyidah Aishah (may Allah be pleased with her) informed him that she was with the Prophet (peace and blessings be upon him) on a journey while she was young. He (peace and blessings be upon him) said to his Companions: "Go ahead, go ahead." Then he said: "Come, let us race." So I outran him (peace and blessings be upon him) in the race, that is, I won. After that, once again I was with him (peace and blessings be upon him) on a journey, and he (peace and blessings be upon him) said to his Companions: "Go ahead." Then he said: "Come, I want to race with you." But I had forgotten the earlier race, and my body had become heavy. I said: "O Messenger of Allah, a race in this condition?" He (peace and blessings be upon him) said: "You will certainly do it." I raced him (peace and blessings be upon him), and he (peace and blessings be upon him) won. He (peace and blessings be upon him) said: "This is for that race."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السبق والرمي / 19758