In fact, the Church has recognized eight positions of prayer and worship: standing upright, sitting, inclining of the head and neck (what is called a “bow”), bowing at the waist (”deep bow”), touching our forehead to the floor (”bow to the earth” popularly known as a “prostration”), bending one’s knees (”kneeling”), standing on one’s knees (also, improperly, called “kneeling”), and holding a bow to the earth (”full prostration”).
There is a ninth action that is seen in many churches today a bow with the addition of touching one’s hand to the floor. That is either a pietistic addition to a deep bow or a replacement of a prostration. In the latter case, I believe it was begun by people who could no longer make a prostration because of their health, but has been taken over as a “replacement” prostration.
The eight actions are performed by both the clergy and the laity at various times in the services. Though most eliminate as many as five of the actions, replacing them with just three standing upright, bowing the head, and sitting whether appropriately or inappropriately. Appropriate sitting is when it is called for, such as during the Kathisma, while inappropriate sitting is done by custom, such as when the Royal Doors are closed or during all litanies.
Each of these eight positions has its own distinct term in Greek (and in Slavonic). Only in English have we not established appropriate terminology as yet. Thus, we speak of “kneeling” which should mean bending a knee to the ground and manage to confuse all activities in which a knee touches the ground. We speak of “prostration” despite the fact that lying on the ground (being prostrate) is not one of the eight actions.
As a result, there is a lot of confusion, especially when reading the fathers or the Canons of the Church in translation. The same confusion often exists because the words for “prayer” and “worship” are also often confused and assumed to mean the same thing when they, also, are quite distinct in Greek and Slavonic.
So, when the Fathers speak of “standing,” we need to be very careful to know which term they are using because they can be referring to “standing on one’s knees” as well as “standing upright.”
At the same time, when they speak of not “kneeling during prayer,” we need to be very careful not to assume that they are categorically saying that no knee should touch the ground. Such things are simplifications due to the limitations of English terminology and not their intent at all.
From here...
http://www.dneoca.org/articles/responsekneel0795.html
Beware the OCA and its usually self serving opinions, netmilsmom.
BTW, the Greek Church kneels on Sundays (except between Pascha and Pentecost), the Canon notwithstanding. It drives most of the Slavs crazy!
I was surprised that the list did not include a genuflection.