Anyone can execute a block or a strike, but not everyone can do it with balance, power, flexibility, and style. The quality of the execution is what is most important. If you follow the young lady in the video closely, you can see that she has a very good block. Notice when Calasanz swings how she naturally drops back and moves her head to evade the strike. She then immediately returns a counterattack. At this point in her training, will she be able to hurt someone? No, but it is crucial to teach good technique first and then develop more strength and striking power. There is a difference between training in martial arts and boxing as a way of life and training for competition. Nobody is really ever ready for the streets because what goes on there is very unpredictable. If you want to produce a good street fighter, then you need to find someone who has no fear. Technique for this person is just icing on the cake.
Calasanz Self Defense and Sports Training information