Among the items in Signs of the Times on Aug. 4 is a notice that the Vatican says flexibility allowed on posture after Communion, even though the General Instruction of the Roman Missal, No. 43, states that all are to remain standing until the end of Mass. The reason given for this statement by the Congregation for Divine Worship and the Discipline of the Sacraments is worth noting and should be observed as a principle regarding other postures at Mass, such as standing for the eucharistic prayer: The mind of the prescription of the General Instruction of the Roman Missal, No. 43, is intended, on the one hand, to ensure within broad limits a certain uniformity of posture with the congregation for the various parts of the celebration of Holy Mass, and on the other, to not regulate posture rigidly....
That explanation is in accord with the much-ignored principle of the Constitution on the Sacred Liturgy, No. 37, which insists that even in the sacred liturgy the Church does not wish to impose a rigid uniformity in matters which do not involve the faith or the good of the whole community.
Charles E. Miller, C.M.