If actual Ruku and Sujud cannot be performed:
• pray sitting and use head gestures;
• the Sujud gesture must be lower than the Ruku gesture.
Do not raise a cushion, board or other object merely to bring the forehead to it. If an object happens to be raised and the person's own head still bends sufficiently for the required gesture, the prayer is valid because the legal act is the head gesture itself.