[Tango-L] On Axis, Off Axis

[Mallpasso@aol.com]

Dear All:
 
According to the Oxford dictionary (gotta go back to the real source  of 
English, right?), axis is defined as:
 
"an imaginary line about which an body rotates"; or "line that divides  a 
regular figure symmetrically";  the former describes a body in motion the  latter 
describes a body physically with respect to it's shape but says nothing  
about movement or motion.  None of the above describes a body in static,  i.e., 
standing still as when a dancer pauses.  So it appears the usage of  the word is 
can be applied when a dancer is in rotational motion only.  A  better word 
would be "balance" for when a dancer is not in motion or just  standing still.
 
I'm guessing the first dance who used the word "axis" in application to  
dancing wasn't a physicist...  ;-)
 
My 2 cents.
 
El Bandido de Tango
 
 
 
In a message dated 5/6/2006 10:17:19 Pacific Daylight Time,  
jayrabe at hotmail.com writes:

Some  points of observation/analysis on Evan's thread of maintaining axis in  
close-embrace...

As always, the simple expression "on-axis" can be  interpreted in a lot of 
different ways.

If I stand flat-footed,  with my center of mass directly over the center of 
my foot. I am clearly  on-axis, in the most literal sense. If I lean forward, 
putting my center  of mass above the ball of my foot. I am still on my axis, 
in the sense of  fully supporting my own weight, but now my chest has moved 
about 4"  forward (a maximum of 1/2 the length of my foot, per Even's 
analysis of  center of mass not extending beyond the edge of the 
"foot-print").  Mechanically, moving my chest forward is equivalent to moving 
my feet  back. If my follower does the same, the consequence is that now 
there is  more space between our feet, and we can dance without knocking 
knees. Note  that, in this position (call this "position-1"), it is not 
necessary that  either dancer be exerting any forward pressure on their  
partner.

Teaching this concept (weight on balls of feet) can be  challenging. One 
device used by a lot of instructors is to have the  dancers apply forward 
pressure to their partner. Alex uses the expression  "2 pounds of force." In 
order to apply forward pressure, a person must  push with their feet, which 
has the consequence of putting their center of  mass/force over the balls of 
their feet. One note: It is highly important  that the force vector be in a 
direction parallel to the ground, that is,  directly forward into their 
partner, with no downward component. In this  position (call this 
"position-2"), let's say that the individual dancers  are still "on their 
axis" in the strictest sense of being able to maintain  their position 
without falling if their partner steps back.

Now  consider the extreme ("position-3"), in which the dancers put so much  
forward pressure on their partner that, if one were to step back, the  other 
would fall (I've heard the term "apilado" used to describe this type  of 
embrace). But even with this much force, per Even's analysis, the PAIR  is 
still "on axis" (but now it's a shared axis), because they can, as a  couple 
in an embrace, stand motionless without falling, because the leader  fully 
receives and returns (balances) the force back to the  follower.

Note there is a continuum of possibilities between positions  2 & 3 in the 
amount of force given & received. IMO it isn't so  important how much 
pressure is given. The important things are: no  downward force; weight on 
balls of feet (= space between the feet); and  energy directed into their 
partner for a good "tango  connection."

One interesting thing about position 3 is that the extra  force sent by one 
and fully balanced by the other seems to create a  coiled-spring-like effect, 
storing energy, so that when I do a lead, it is  possible to release that 
energy into very fast/large/dramatic  moves.

Finally, all of these principles apply to open embrace as well  as close 
embrace. In close embrace, the forward force is applied with the  chest, 
while in open embrace it is applied with the points of contact in  the 
hands/arms.

J
www.TangoMoments.com


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