Is it permissible for a worshiper to place one foot over the other during prostration (sujud) and sitting if he is unable to touch the tips of both feet to the ground due to pain?

Sujood (prostration) on one foot is sufficient according to the majority of scholars who do not consider it obligatory to prostrate on body parts other than the forehead from among the seven limbs. Even the Hanbalis, who consider it obligatory to prostrate on both feet, waive this obligation in cases of considerable difficulty. Similarly, sitting on one foot is sufficient.