Are there any Internal Arts/Lineages that move on the balls of the feet instead of the heels? Particular I was wondering about Sun Taijiquan, but I am also interested in the rest of the arts.
feet have balls?
My understanding is that all martial arts tend to have the weight slightly forward on the foot 90% of the time (the 'ball' of the foot... in chinese is called the 'bubbling well')
There are a couple of moves where the artist 'spins' using the heel-(like the spinning locus kick in Thai Ji) when spining the heel is a safer option because if something impeds your spin (a snag) no big deal for the heel... if something snags a spin on the ball of one foot your ankle or knee may get twisted or torqued.
In fighting, phyisically or verbally, one is more agile on the balls of one's feet- hence, in boxing, debates and political interactions- when someone is being over-whelmed the idim is often " that exchange got to him- he's on his heels now" (being "on the heels" implies off balance and scrambling for footing)
The weight back, on the heels is not a balanced place to be in most circumstances.
Though one is more mobile on the balls of the feet, which is good for striking, throwing on the heels yields more power IMO. I'm talking about when two people are locked up. Turning on the heels, as opposed to the kd 1point(ball of foot), connects you directly into your ITB band(thick fibrous tissue on the outer thigh) which gives you a better connection to your hip. Turning on the kd 1 acupuncture point puts too much stress on the knee possibly resulting in an ACL tear.
Of course the best way to measure would be to have wrestlers from both camps, of equal skill, try to throw each other.