One of the goals in partnership dancing is to move as "one" on the dance floor. "One" what??? The answer is "one" two-headed four-legged animal. The dance frame connects the two two-legged animals together to become a single entity. The frame alone, however, is not enough to synchronize the movements of the four legs. Two of the four legs (the leader) have prior knowledge of what is going to happen. There must be some kind of communication to the other two legs for synchronous movement to occur. In a nut shell, the leader must initiate all movements from the supporting leg in order for the follower to feel what to do.
A two-legged animal has several ways it can move. When moving on a level surface or going down hill, a person can reach out with their free foot and rock their body weight forward on it to move. However, when going up hill, the person must power from the supporting leg to move the body weight. There are other ways to move as well, but these two are the ones we need to understand.
Beginner dancers typically move their free leg first to take a step in partnership. The follower cannot feel the free leg moving, let alone figure out how to respond. The leader must power from the supporting leg as if he were dancing up hill all of the time. When the leader powers from the supporting leg, the follower will feel it and power from her supporting leg as well. It shouldn't feel like the follower is being pushed around the floor. The follower is adding to the power of the movement from her supporting leg. We now have two supporting legs providing the power for the movement.
We now need to define: What is a supporting leg? From previous articles, you know that a free leg still has about 2% of the body weight and the supporting leg has the other 98%. However, we have not talked about which leg is the supporting leg when you are on split weight. In this case, both legs are the supporting leg. When a forward step is taken, the body weight moves from the supporting leg towards the free leg. At some point, the body weight is equally on both legs. The back leg is pushing forward and the front leg is pulling forward. The power of the movement moves from the original supporting leg towards the free leg, and transitions through split weight to the new supporting leg. As you can see, both legs are working all of the time.
Try to envision this: You are going to jump sideways across a creek (full of piranha man/woman eating fish) about 3 feet wide. Your right foot is your supporting leg and you are going to reach across the creek with your left leg and hop across to the other side.
This method of powering the body movement is what makes Foxtrot dancers move so smoothly across the floor.
The concept of moving from the supporting leg and the power transfer to the new supporting leg is critical to developing an obvious lead. Moving from the supporting leg is hard to turn "on" just on the dance floor. You need to make this type of movement part of your daily life. Move like you are always walking up hill. Happy dancing.