The musical rhythm is the arrangement of the sounds with base in the distinction among those with impulse character, called ARSIS, and those that have character of rest, called THESIS.
This classification starts on the smallest groups of sounds and goes relating them in more and more wide contexts, through different stages of rhythmic synthesis, in a unifier process.
In Gregorian chant the synthesis is carried out by means of three stages:
- elementary rhythms,
- groups and
- great rhythm.
Chironomy is the way that conductor uses to move his hands in order to show the rhythmic elements of the musical work and their different shades; the purpose of Chironomy is to achieve the most perfect interpretation.
The two fundamental movements are those that describe the arsis and the thesis.