Spins
Spinning involves both dancers turning together as one unit. Dancers
often perform a spin by converting their linear motion into angular
motion and revolving around a vertical axis halfway between their
bodies.
Leading for spins is orchestrated by the Lead creating a turning
action with his body combined with light pressure of his right hand
on the Follow. The right hand should not be used to pull or push the
follow. The Lead's right hand is a solid part of the frame. When the lead creates a turning
action, or torque, the frame becomes a tension force between the
dancers. While spinning, this tension is the force that keeps the
couple from separating when inertial forces resist the change in
direction.
Viewed from above, a pair of dancers performing a simple spin looks
something like this:

The speed of the dancer's rotation will change depending the
distance between their bodies and the axis of rotation. In the image
above, the axis of rotation is a red speck halfway between the two
dancers. If the dancers were to expand their frame then their
rotational speed will slow down. Conversely, if the dancers were to
move closer together by tightening their frame, their rotational
speed will increase.
When dancers want to perform very rapid spins, they will form an
extremely small frame. This may take the form of one dancer standing
directly behind the other with both dancers holding on to each other
or by standing face to face with feet alternating (the Lead has one
foot between the both of the Follow's and vice versa) and holding
tightly. When the frame is small enough and the timing is right, the
Lead will create an external force and both dancers will spin while
sharing a center of gravity directly over the smallest base their
feet can create. Timing is critical for initiating the spin and for
each dancer moving their feet. Both dancers must lift and set down
their corresponding feet at the same exact time to prevent tripping
or loss of balance.
Bibliography