Shevuot (Oaths) 17 - Different Kinds of Bowing Down
If one became ritually impure while in the Temple and before leaving bowed down, or tarried long enough to bow down, he is liable to the "variable" offering.
There are three kinds of bowing down are mentioned in the Scripture. "Kidah" means bringing one's face down to the ground from a standing position, with no more than his thumbs to support him in front. Batsheva was able to do it , and the High Priest would attempt it on Yom Kippur in order to keep awake. "Keriah" is kneeling down, and "Hishtachavaah" means complete prostration on the ground, with arms and legs extended.
Rava asked, "If one, upon being contaminated, suspended himself in the air of the Courtyard, not touching the floor, is he liable for an offering?" Does "tarrying long enough to bow down" imply being able to actually bow down, or does it not? - No answer is given to that question.
Art: Sir David Wilkie - Woman with a Baby Kneeling