Musnad Ahmad 5:558

Aswad ibn Amir narrated to us, Sharik narrated to us, from Ibn Umayr. Sharik said: I said to him: "From whom, O Abu Umayr? From whom did he narrate it?" He said: "From Nafi ibn Jubayr, from his father, from Ali, who said: 'The Messenger of Allah, peace and blessings of Allah be upon him, had a large head, was tinged with redness, had thick palms and feet, a thick beard, and a long line of hair [running from the chest to the navel]. He had large joints. When he walked, he would walk as if descending a slope. He would lean forward in his walk. He was neither short nor tall. I have not seen anyone like him before him, nor after him, peace and blessings of Allah be upon him.'"