When we started they were simply called the role of the man and the role of the woman, without this denoting something bad or negative, that was simply the way it was and that is how it was accepted. Over time other terms were used, mainly under the influence of the English speaking world as the role that guides or "leader" and the role that follows or "follower". Personally we are not bothered by any of the terms but since there are those who feel uncomfortable, misqualified and devalued with the term, it may be worthwhile to look at other options.
The easiest is to compare the roles of dance to what happens in music, when there is someone who composes a melody and then there are those who execute it with their instrument by reading a score and adding their interpretation.
To be able to write a melody, no matter how simple it is, you need to learn music...
To be able to dance with a partner, however simple the dance may be, you need to learn body codes (movements) to be able to express yourself and make this message be interpreted by another person.
So you could say that the leader is the one who has the ROLE of COMPOSER and the follower is the one who has the ROLE of INTERPRETER:
Through an acquired language, the composer combines ideas, movements and proposes them to the interpreter, who translates them into movement, contributing and complementing them with his/her musicality, sensitivity and all the possible nuances.
The better the composer's ability to compose, the better the interpreter's ability to translate his/her indications into movements. The better the interpreter's ability to understand, the greater her/his contribution will be in the richness of what she/he translates into movements.
That is to say that she not only does what she/he is told but also adds her/his creativity, such as musical and expressive richness (quality of movement and ornamentation for example).
Our body is our instrument, the technique exercises, body awareness, methodical and progressive practice, musicality in its entirety are fundamental key to the full development of these two roles of the dance. But this is another subject that requires more details.
I hope you enjoyed the reading and that this has contributed to expand your preception.
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