Poyasny ("little bow", literally belt bow) and zemnoy poklon ("great bow", literally "ground bow") are different kinds of bows used in an Eastern Orthodox worship service.
The different kinds of bows one could encounter at an Eastern Orthodox service are shown in the picture on the right. Only types 2, 5 and 6 have their own independent meaning and rules of usage; the other types are either "lightened" or "weighted" versions of these three "basic" versions.
Strict rules exist as to which type of a bow should be used at any particular time. The rules are very complicated, and are not always carried out in most parishes. Old Believers are generally much more punctillious about bows in comparison with the official Orthodoxy.
It is also important to note that traditionally, the Eastern Orthodox service has no kneeling in the Western sense of standing on one's knees. While kneeling for prayer was customary in the primitive church, the Byzantine tradition did not maintain it, and the people stood traditionally. In the 20th century in some western countries, some Eastern Orthodox churches have begun to use pews and kneelers and so have begun kneeling in some parts of the service.
Orthodox tradition specifies that the faithful are to stand rather than kneel in prayer from Pascha (Easter) until Pentecost, and on all Sundays throughout the year, in honour of the Resurrection. That dates from the time when kneeling was more prevalent than it is today. There is some variation in interpretation, with some traditions, notably in the Greek church, extending this prohibition on kneeling to also preclude prostrations. Within the Slavic churches, there is regional variation in practice, with some places avoiding prostrations on Sundays and others making the usual prostrations regardless of the day of the week.
The Russian Old Rite, which reflects the praxis of the Russian church prior to the 17th-century reforms, which brought it in line with Greek practice as it stood at the time, itself the result of revision over the centuries, explicitly requires prostrations to be made at certain points during the services regardless of whether it is a Sunday, including at the end of Shine, Shine throughout the paschal season. That would seem to suggest that the canons forbidding kneeling on Sundays were not anciently understood to also prohibit prostrations. Indeed, the rubrics of the services require the faithful to prostrate before the Cross on the Third Sunday of Great Lent and also on the Feast of the Exaltation of the Cross, even if it falls on a Sunday.