The World Federation One Stop Fiqh

Ruling 1057

If a person’s forehead is raised involuntarily from the place of sajdah, in the event that it is possible to do so, he must not let it touch the place of sajdah again; this is considered to be one sajdah, whether he has said the dhikr of sajdah or not. If he cannot keep check of his head’s movements and his forehead involuntarily touches the place of sajdah again, this is still considered to be one sajdah. However, if he has not said the dhikr, the obligatory precaution is that he must say it but he must do so with a general intention of attaining proximity to Allah and not with a specific intention [i.e. not with the intention of it being an obligatory dhikr of the prayer].