Striking Of The Breast At The Beginning Of Mass.

[LinaSt.Cecilia2772]

Okay so i have been in like this thing with recording the daily masses that come on EWTN and watching them as i go to bed, and i noticed that at the beginning of mass when the recite the act of contrition that they like hit themselves on their chests after they say "And i have sinned through my own fault." I was a little confused cause i had never seen that done before, and i was wondering why it's significant to the prayer and the mass. Does it mean anything in particular??

[cappie]

In the revised English translation of the Roman Missal to be implemented and the end of the year, the first half of the Confiteor ends with an admission of personal guilt for our sins. As we say these words, we strike our breast three times in a sign of penitence:

mea culpa, mea culpa, mea máxima culpa.
through my fault, through my fault, { Sir. 20:2b }
through my most grievous fault;

The repetition of this admission of guilt adds to its severity. We do not say “The devil made me do it, the devil made me do it, you can bet the devil made me do it,” but accuse only ourselves for our sins. We beat upon our breast with a closed fist, like the tax collector who prayed from his heart, “God, be merciful to me a sinner!” (Luke 18:13) Cardinal Ratzinger addressed the gravity of these words and this gesture:

We point not at someone else but at ourselves as the guilty party, remains a meaningful gesture of prayer. … When we say mea culpa (through my fault), we turn, so to speak, to ourselves, to our own front door, and thus we are able rightly to ask forgiveness of God, the saints, and the people gathered around us, whom we have wronged. (The Spirit of the Liturgy, p. 207)

Rev. Romano Guardini explained that the meaning of this gesture of contrition depends upon it being done properly:

To brush one’s clothes with the tips of one’s fingers is not to strike the breast. We should beat upon our breasts with our closed fists. … It is an honest blow, not an elegant gesture. To strike the breast is to beat against the gates of our inner world in order to shatter them. This is its significance. … “Repent, do penance.” It is the voice of God. Striking the breast is the visible sign that we hear that summons. … Let it wake us up, and make us see, and turn to God. (Sacred Signs)

The Douay Catechism (from 1649), a question-and-answer catechism on the doctrines of the Church, included a chapter expounding the essence and ceremonies of the Mass. It explains that the reason for striking the heart is “to teach the people to return into the heart” because it “signifies that all sin is from the heart, and ought to be discharged from the heart, with hearty sorrow.” (p. 125)
Praying the Mass: The Prayers of the People, pp. 37-38