Demonstration
View the clip to get an idea of what we're aiming for.

Pedalling, side view - merengue_lower_body_side.avi (5.2 Mb)

Nathan is on the left, presenting a side view of the lower body action. Shirin is on the right, presenting a front view. Notice how their hips swing with every step.

Preparation
Now, we'll begin by performing this exercise on the spot. I recommend that you try this exercise barefoot or in socks at first. It will help you develop pressure sensitivity through the soles of your feet, and use that to give you feedback about your performance.

Performing the exercise slowly develops your control; performing it faster increases your fluency. Always go slow at first.

Description
Stand with your feet together, toes pointing slightly outwards, weight completely on your left leg, ready to step onto your right.

1. Pick your right foot slightly off the floor and;
    
2. Place just the front half of your foot, specifically the ball, on the floor. You should sense the contact by feeling a slight increase in pressure on the ball of your sole. This begins the process of foot placement.
    
3. Lower your heel until it makes contact with the floor. Again you should try to sense the slight increase in pressure, now through the heel of your foot. Once the heel is down, your whole foot should now be in contact with the floor. This ends the process of foot placement.
    
4. Straighten your knee by easing it backwards until it is over your heel. You can feel it pulling your body weight to your right, and confirm it by sensing a further increase in pressure through the sole of your right foot. You can control how quickly (or slowly) your weight shifts by how quickly (or slowly) you ease your knee backwards. This begins the process of weight transfer.
    
5. Continue moving your hip to the right until you feel the toes (of your right foot) relax. If you feel the tips of your bigger toes start to peel off the floor, you've gone too far. Your ankle, knee and hip joints should now be stacked on top of each other. This ends the process of weight transfer.
    
6. Next, you'll need to relax the muscles at the top of your hip. To do so, take a deep breath: in through your nose and out slowly through your mouth. As you exhale, you should feel your rib cage drop, your muscles relax and your whole body sinking onto your hip. We call this process settling your weight.
    
7. Finally, with your weight still settled, pitch your body forward slightly so that your toes just start to grip the floor again. Your weight should be on the front part of your foot, ready for your next move.
    

Principles
The phases of movement are foot placement, weight transfer, relaxation, and preparation. It is achieved by positioning the ball of the foot, ankle, knee and hip joints in that order from the ground upward, in what we call an “upward joint cascade”.

Refer back to the video clip: merengue_lower_body_side.avi (5.3 Mb)

The side view is most useful for observing the action of the foot, ankle and knee. By moving the slider, observe joint cascade in the way Nathan takes his step. Not only do the joints move in the proper order, but the speeds at which the joints move relative to each other is even. This results in a smooth cascade. Compare his action with Shirin's who has faster ankles and slower knees, giving an action that stresses the beats and is lighter in between.

Next view:

Pedalling, front view - merengue_lower_body_front.avi (5.3 Mb)

Pausing the clip and using the slider, notice how after the knee is straightened, the top of the hip aligns above it. Relaxing (or reducing tension in) the muscles around the hip causes settling, which can be seen by: a slight increase in deflection of the hip outward from the perpendicular (to the floor); and a more prominent lateral roll of the hip backwards. This causes the hips to tilt into the direction of your next step, as is observed from the belt-lines of both Shirin and Nathan.

Goals
Continue with the practice until you're consciously proficient, and then try it stepping onto your left. Your aim is to pedal using each leg in alternation, just like in the clips.