'Abdullah ibn Shaqiq said

“I asked 'A’isha (may Allah be well pleased with her) about the voluntary ritual prayers of Allah’s Messenger (Allah bless him and give him peace), and she said: ‘He used to spend a long night performing the ritual prayer while standing, and a long night while sitting, so if he recited the Qur’an while standing, he would bow and prostrate from a standing position, and if he recited while sitting, he would bow and prostrate from a sitting position.”