Many beginner and even intermediate and advanced dancers have a difficult time moving gracefully while dancing Samba. They have an even harder time trying to lead it. I believe that the timing of Samba as well as the basic dance concept that "every foot step is a complete weight change" has a great deal to do with it.
Samba has a 2/4 music time signature (two beats to a measure) and the dance step timing is "1, ah, 2". It is NOT "1, and, 2"!!! An "and" is 1/2 of a beat and an "ah" is 1/4th of a beat. This is very important to understand because it is very different dancing an "and" than trying to dance an "ah". There are three steps in a Samba measure or dance element. From a duration standpoint, the first step is 3/4th of a beat, the second step is 1/4th of a beat and the third step is 1 whole beat. The 1st step is almost a whole beat, the 2nd step is just a fraction of a beat and the 3rd step is 1 whole beat. The basic footwork is "Ball/Flat, Ball, Ball/Flat". The key is: "How do I execute the fraction of a beat ("ah") step?"
Remember that the supporting leg is always the boss. Movement originates from the supporting leg. This is the only leg that your partner can feel. Samba has a "Down, Up, Down" (1, ah, 2) feeling. Again, the footwork is "Ball/Flat, Ball, Ball/Flat". The slight "down" feeling in the knee of the SUPPORTING leg allows it to power the FIRST step and it has a Ball/Flat (Down) footwork. The SECOND step footwork (the "ah") is always a "Ball" only ("Up") step. In Samba, the body weight is never balanced over the "ah" step. The second step (the "ah") feels like it is beside and slightly outside of the body because the leg is a little longer (because of the "ball" only footwork). This longer leg creates a slight pendulum action in the body. The THIRD step is an in-place "Ball/Flat" (Down) step, getting ready to take the next step.
Samba employs Latin/Cuban motion, meaning that the legs start at the bottom of the rib cage and extend to the floor. Above the bottom of the rib cage (the body) remains relatively still. The Latin/Cuban Motion is a little different than what is considered normal Latin/Cuban Motion. There is not a complete hip switch on the "ah" step since the "ah" is a "Ball" only step and is only 1/4th of beat. The body weight remains over the 3/4 beat step or the whole beat step and is never directly over the 1/4th beat ("ah") step. This creates a slight side-to-side action when moving from element to element. The stillness of the upper body creates a slight pendulum action from front-to-back and side-to-side.
Let's look at a Samba "Forward and Backward" basic pattern starting forward with the left foot. There is a slight prep action before the first step. The supporting leg (in this case the right leg) is slightly bent. This bent leg along with pushing off slightly with the supporting ankle, moves the body forward to the left foot. As the weight moves forward to the 1st step ("Ball/Flat"), the leg bends slightly ("Down"). The body weight remains over the left (supporting leg) as the together 2nd step ("Up") is executed as a "Ball" only step. The weight returns to the left foot ("Ball/Flat") on the in-place 3rd step with a slight bending of the leg in preparation for the next step. There is not enough time to have a complete weight change to the 2nd step ("ah") because it is only 1/4th of a beat. All of the other patterns are executed in a similar manner.
One of the more challenging patterns to lead and dance gracefully is the "Volta". A "Volta" is simply a front crossing step action. The timing of the pattern to be discussed is "1, ah, 2; ah, 3; ah, 4" (moving right) then "1, ah, 2, ah, 3, ah, 4" (moving left). First, how does the dancer transition from moving forward and backward (as in the forward & backward basic) to moving sideways? In the Forward and Backward basic, the dancer pushes off from the supporting leg to move forward then pushes off from the supporting leg to move backwards. After the forward element of the basic, simply push to the side from the supporting leg (from the "Down" action of the supporting leg) instead of pushing backwards.
Now that we know how to start to move to the side, how does the "Volta" element work? The footwork is critical in executing a "Volta". In this example the footwork is 1:"Ball/Flat"(Down), "ah":"Ball"(Up), 2:"Ball/Flat"(Down), "ah":"Ball"(Up), 3:"Ball/Flat"(Down), "ah":"Ball"(Up), 4:"Ball/Flat"(Down), moving to the right. The same is true when moving to the left except that the other foot is crossing in front. The crossing foot is always on the whole beat (the 1, 2, 3 or 4). The lifting action of the "ah": (Up) step makes room for the whole beat step to move across in front. The slight lowering action (Down) on the "Ball/Flat" allows the supporting leg to power the weight change. The use of Contra Body Movement (CBM) allows for a more graceful and controlled "Volta" action.
Think of the "ah" step as having a tack stuck in the ball of the foot. You can feel the tack in the ball of your foot but it doesn't hurt much. You know it will really hurt if you put any amount of pressure on it. This forces the dancer to keep most of the weight over the whole beat step during the movement. This action is true for all Samba patterns. In the "Volta" pattern described above, notice that there are two whole beats (4 & 1) together in the middle of the pattern. This is where the transition from traveling right to traveling left is made.
Moving from the supporting leg, the correct footwork, the Down, Up, Down, action, the pendulum action of the body, the tack in the foot and CBM, all are elements involved in creating a powerful, controlled and graceful Samba.