Double weightedness is good for pushing and pulling, such as pushing a car, lifting weights, or a tug-of-war. Fighting is much more dynamic and requires the transfer of the power base-stance; to accommodate the best focused wave. Would anyone have a fixed double weighted stance when they surfed, or snow boarded?
“If your weight is back-weighted, basic bio-mechanics will show that you will be prevented from delivering all of your force into the target. “
The Xingyi Quan of the Chinese Army, by Dennis Rovere, page 18.
Having your stance back-weighted also leads to another problem, namely, a tendency to straighten the front leg. Any low kick, such as a Xingyi horse kick targeting the straightened knee, would easily cause it to hyperflex, severely damaging it.”
There are two universal defense against kicks to the knee:
1) angling the knee forward, so the kick gets hit by the front striking area of the knee,
rather than the more flexible joint;
2) when in a Cat Stance, T-Stance or San-Ti; the lesser weight of the front foot is shifted backward toward rear leg, and
a) the front leg evades the kick by repositioning or
b) the front leg’s knee is repositioned to hit attacker with knee or shin strike.
An external kick is limited by biomechanics, an internally generated kick is not.
When one is seasoned by sparring and/or combat; they always keep the front leg slightly bent; one who spends all of their time on forms/Katas only; does not. When you advance, your training prevents this.
A major foundation of Traditional Internal Chinese Martial Arts is the stance concept of having either leg being empty or full. This is not weight, although sometimes they are the same. This is fullness of Qi, stance rooting and a centering of the driving energy.
This is the generator of the wave flow force, using the whole body weight being directed into the strike. Kinematics deals with this somewhat, not biomechanics.
“Sung Shi-Jung
…Therefore, in Hsing-I never equally share the weight on your two feet.”
Hsing-I, Chinese Mind-Body Boxing, by Robert W. Smith, page 98.