Sayyiduna Wa'il bin Hujr (may Allah be pleased with him) said: I prayed with the Prophet (peace and blessings be upon him). When he (peace and blessings be upon him) prostrated, he spread out the left foot and kept the right one upright.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18312