It is my observation that few people had been observing the rubric to strike their breast during the “I confess” in the Penitential Rite at Mass.  With the new translation, now would be a good time to remind everyone that the rubric is still there during the Penitential Act (N.B. the new title of the Penitential Rite).  With the revised translation, which now fully translates the latin of the Confiteor (I confess), we say in English the threefold confession, “through my fault, through my fault, through my most grievous fault” (which had always been there in the Latin text, but which had been simplified in the former English translation).  The logical question arises: do we strike our breast once, or three times.  A useful answer to this question can be found on ZENIT, as printed below.

Source: http://www.zenit.org/article-33981?l=english

Q: In the new translation of Mass according to the English-language Roman Missal, I find myself wondering about a certain lack of specificity in the Confiteor. The missal indicates that those reciting the prayer are to strike their breast at the point where they say, “through my fault, through my fault, through my most grievous fault.” I am old enough to remember the threefold striking of the breast in pre-Conciliar days, but wonder if this practice has been maintained elsewhere in the Church by the other language groups that use the Roman Missal. Is there a generalized practice? Or is the perceived lack of specificity in the new missal merely an indication that one strike of the breast is expected? — A.L., Gallitzin, Pennsylvania

A: The perceived lack of specificity is in the original Latin rubric which says, “[P]ercutientes sibi pectus,” whereas the extraordinary form specifies that the breast should be struck three times.

There is, however, a slight but noticeable change in translating this rubric. The former translation, with only one admission of fault, said that the faithful should “strike their breast,” thus specifying a single strike. The current translation says, “[A]nd striking their breast, they say:” before the triple admission of fault.

This use of the gerund indicates a continuous action, and so I would say that even if a number is not specified in the rubric, the use of a dynamic expression implies that the number corresponds to the times one admits to personal faults. I think that this is also what would come naturally to most people in any case.

This would be confirmed by the practice in Spanish- and Italian-language countries, which have always maintained the triple form in the “I Confess.” The Spanish missal translates the rubric as “golpeándose el pecho, dicen:” which could mean either once or several times. In these countries it is also common practice for priest and faithful to strike the breast three times.

Although the Second Vatican Council requested the removal of “useless repetitions,” it must be said that not all repetition is useless. Some forms of communication necessarily use what is technically called redundancy, that is, reinforcing the signal carrying a message more than would be strictly necessary in order to overcome outside interference and stress its importance.

The triple repetition of words and gestures in the Confiteor could be considered such a case. With the former translation it was fairly easy to omit the gesture of striking the breast or pay scant attention to its meaning. The triple repetition underlines its importance and helps us to concentrate on the inner meaning of what we say and do.

It must be admitted, though, that the above argumentation is not watertight, and a single strike could also be a valid interpretation of the rubric.

Answered by Legionary of Christ Father Edward McNamara, professor of liturgy at the Regina Apostolorum university.