Musannaf Ibn Abi Shayba 3:331

'Abbad ibn al-'Awwam narrated to us, from Khalid, who said: I saw Abu Qilabah, when he would prostrate, he would begin by placing his knees [on the ground]. And when he would stand, he would lean upon his hands. And I saw al-Hasan fall [into prostration], and he would begin with his hands, and he would lean [upon them] when he would stand.