It seems as though the frame comes up in almost every article I write. It may be the most important physical part of Ballroom Dancing. The frame is involved in almost every aspect of the partnership, movement, feeling, etc. It is the primary source of the "partnership feeling". The frame is the fundamental starting point for everything "Two-headed Four-legged".
The "Partnership Feeling" is a feeling that can only be felt while in partnership. It is unique to the partnership. An individual dancer can't create the "Partnership Feeling" alone. The feeling you have when practicing a specific element by yourself is different than the feeling you have when you are dancing that element in partnership. The feeling is created by combining the two partners into a single entity, the infamous "Two-headed Four-legged Animal".
The frame establishes the two partners' physical relationship to each other. It maintains the partnership offset that is one of the keys to "Four-legged" movement. The frame adjusts for the difference in the size of the partners. It allows power to be supplied by either partner. The frame gives the leader the ability to lead the different "Dance Positions" ("Closed", "Promenade", "Outside Partner", Open", etc.) that are required for specific movements.
The frame is the primary communication link between the partners. It determines the center of the partnership and the shape of the partnership. Vertical movement, horizontal movement and rotational movements are all under the influence of the frame. The physical and communication properties of the frame allow many "Invisible (logical) Connections" to be developed by the leader.
Just because the partnership is physically connected through the frame, does not mean that the power goes through the frame connection. The power goes through the logical center of the partnership. Each partner has a center of gravity and the partnership has its' own center of gravity. The partnership center of gravity is not a physical connection, but a logical connection. The frame connection allows the dancers to be able to feel and use the logical center of the partnership. As in all four-legged movement, the power for movement comes from the supporting leg and goes through the logical center of the partnership.
The man's right arm in the frame does not hold the lady in position; it simply defines the partnership relationship so she can move around within the space as necessary. The frame connection has a forward feeling toward each partner. The follower provides a connection that is equal in strength of the leader. The connection is just strong enough to be able to feel the other partner and is flexible and pliable. The frame connection lives and breathes.
The frame communication also allows the follower to be able to feel weight changes from foot to foot, rise and fall through the body, the legs and the feet and body shape. The connection allows the leader to feel the followers' power in order to control the momentum of the movement.
No matter what position the dancers' arms are in (even in a solo turn), they are still a frame. As long as there is physical contact between the partners, there is a connection. There are dance elements that have just one connection ("Open Breaks", "Crossover Breaks", "Continuous Hovers", etc.). It is possible to logically feel the free hand of your partner. The free hand of one partner can be felt through the partnership connection to the free hand of the other partner. This doesn't work unless both partners are participating in the movement.
Understanding all of the nuances of the partnership, connection and "Four-legged" movement is the definition of a "Trained Dancer". Becoming a "Trained Dancer" should be every dancer's goal. This will take you from being a "Pattern Dancer" (dancers that just walk through patterns in front of each other) to being a single fluid entity on the dance floor. The purpose of the frame is to allow the two partners to combine to such an extent that the individual dancers disappear and the single "Two-headed Four-legged Animal" emerges.