The general rule of thumb for basic directional movements is to shift the hip and transfer the weight at approximately the same speed, such that they begin and end together, filling up whatever time is allotted to them (e.g. 1 beat for a quick, 2 beats for a slow).
There's actually no "right" or "wrong" in this matter, and there are certainly many examples of exceptions to the rule.
"W.E.S.T." (or "S.T.E.W.", as I like to call it) is the study of the various qualities one can attribute to any movement. The acronym stands for Space, Time, Energy and Weight. Each word describes a quality which spans from one extreme to another. The following is a summary of the qualities:
SPACE:
Direct <----------> Flexible
TIME:
Sudden <----------> Sustained
ENERGY:
Bound <----------> Free
WEIGHT:
Heavy <----------> Light
Any movement can be interpreted in almost unlimited ways, as a combination of different degrees of these four qualities. For example, one moment you could dance a Rumba Walk quite flexible, somewhat sustained, extremely free and slightly heavy. Then you might switch it up and do something more direct, sudden, bound and light.
When we're discussing the speed of the weight transfer over counts 4,1 of the Rumba Basic, we're mostly interested in the matter of Time, which is to say that we're making a decision of whether to dance more sudden, or more sustained. No matter what moment you transfer the weight, whether it be at the very beginning, the very end, or somewhere in the middle of the slow, if you do it all at once, we would describe it as sudden. Take your time and span the entire slow, and the movement is sustained.
The Rumba Basic, like all other movements, can be danced sudden, sustained, or anywhere in between. My theory is that most basic patterns involving simple, directional movement (e.g. the Rumba Basic), should in general be interpreted as sustained. You can make your slows occasionally sudden, but I would recommend making sudden the exception, not the rule. In the end, it's simply a matter of taste. But with too much sudden movement, you will find that your Rumba becomes jerky and restless, which is not a very good representation of the character of the dance. Also, you should consider that dancing is made more interesting through contrast. By using sustained movement as your default, the sudden becomes more exciting in contrast.
Regards,
Jonathan Atkinson
www.ballroomdancers.com
