As dancers evolve through the various stages of Ballroom Dancing from "Individuals" to a "Duality" to a "Singularity", there is a lot of focus on footwork, dance position, partnership, patterns, etc. The body is generally ignored at this stage and may become rigid by default. Even though the body is strong, toned, erect, and balanced, it doesn't mean it is hard and inflexible. The flexible toned body gives the dancer more control of power, movement and feeling. The body should never be inactive or dead.
In the early stages of learning Ballroom Dancing, it is taught that the body remains quiet and passive. This is to allow for more concentration on footwork, partnership, patterns, etc. The dancer is basically built from the floor up. As the dancer's proficiency develops, the action of the body starts to come more into focus. Unfortunately, many times the dancer never develops far enough to include the body. It is also unfortunate that often the student dancer doesn't know that there is any more and settles for where he or she is in the evolutionary process.
The following descriptions are for Ballroom Dancing at the higher levels but I want to let the dancers that are in the evolution process know that these types of things exist and should be an eventual goal. In this article I am defining the body as everything except the legs (from the hip sockets down) and the arms (from the shoulder sockets out). The body is composed of two parts, the "trunk" and the "head".
The body's "trunk" should be alive and active but not animated. If the body is flailing, it is very distracting and often confusing for the other partner. The focused mental concentration of a dancer can literally freeze the "trunk". The mental process should be used for consciousness and awareness and not for intellect, thinking, planning, etc. It takes experience and training to be able to turn off the intellect and just be aware, be conscious. Be patient, it will come as long as you know that it exists. Physicality can turn off intellect and leave just awareness and consciousness. Try this: Use your "trunk" to physically squirm while you are dancing. You will notice that your focus has turned from thinking to feeling (awareness).
The other part of the body is the "head". In particular we are talking about: Head (physical position), Vision (sight), Audio (hearing), and Intellect (thought). The head is a complex appendage that takes some careful consideration.
The head position is a crucial part of the balance and movement of the Singularity. Unfortunately, many female dancers have perceived the idea that their head belongs in one specific spot on their left shoulder. The head should be free to move and be able to adjust balance and contribute to the power of movement. The man's head position a little more stable but is still free to move and adjust.
The head's Vision (sight) is used a little differently than you may think. Sight is used for spatial awareness not recognition. The dancers should not be mentally recognizing other dancers or objects through sight while dancing but just being aware of the dance space.
The heads Audio (hearing) is used a little differently as well. Use the music (hearing) for a physical feeling, not for the intellectual understanding of what you are hearing. Let your hearing be free and allow your consciousness of the music be felt by your body. This one is especially tough for men.
The heads Intellect (thought), as mentioned above, is to be used for consciousness and awareness, not for specific thought. If intellect is used for specifics like head position, visual recognition, conscious hearing, etc., the trunk may become frozen. Allowing only awareness/consciousness, frees the body. The focus is the feeling of the Singularity not outside distractions through intellect.
This all seems very complex, but most of it is enabled by experience, training, etc. The beginning, intermediate and even advanced dancers may struggle with these dance concepts but all dancers should know that they exist. If you are unaware, you will never have the high level achievement that we are all striving for. Bottom line; allow the body to be alive and free.