Narrated 'Imran bin Husain (RA): I suffered from piles. So I asked the Prophet ( صلی اللہ علیہ وسلم ) about the prayers. He said: "Pray standing; and if you are unable, (pray) sitting; and if you are unable, (pray) lying on your side." [Reported by al-Bukhari] .

Narrated Jabir (RA): The Prophet ( صلی اللہ علیہ وسلم ) visited a sick man and saw him praying on a cushion, he threw it away and said, "Pray on the ground, if you can, or else pray by gestures and make your prostration lower than your bowing." [al-Baihaqi reported it and Abu Hatim graded it Sahih (authentic) in Mawquf form (as a saying of a companion, i.e. Jabir)] .

Narrated 'Aishah (RA): I saw the Prophet ( صلی اللہ علیہ وسلم ) praying while sitted in a cross-legged position. [Reported by an-Nasa'i; and al-Hakim graded it Sahih (authentic)] .