Re: Punching

RichD wrote: 
This question came up on a martial arts list.

You want to perform the standard right hand punch (with left foot
forward), as powerfully as possible.

First consider what you mean by "power". You posted to sci.physics, so let's get dimensionally analytical.

P=M/LT^3, which can be broken down into mass accelerating over a time period.

A punch is basically applying your fist moving at some velocity to some part of an opponent's anatomy which will absorb the kinetic energy by deforming, thus decelerating your fist. Generally you want to maximize contact velocity and minimize dwell time, no?

You pose two scenarios with one major difference; the relative velocity between you and your opponent. In the second, you have to deal with the attacker's momentum; after a successful strike you don't want him knocking you down. So you have some options; you can plan on ducking aside and letting him go past you, you can redirect him so he goes past you, or you can stop him WRT you. ISTM that what you do with your feet depends on your choice.

To stop him cold, you want to put your fist in front of his center of mass (in Aikido it's called the One Point, located about three fingers above the navel and two inches "inward") and brace yourself firmly enough to absorb all his momentum which seems to imply not lifting your rear foot at all. Then you have to deal with a body folded over your fist. ;>)

 We consider two different
stances: right foot flat (pushing off the heel), or rising onto the
ball of the right foot.

Now imagine two scenarios:
a) You are attacking the opponent.  The consensus is that rising is
superior, because it brings the calf muscles into play.  Also, the
posture offers greater leverage (and reach).

If I'm going to punch someone, I like to use Bruce Lee's Jeet Kune Do style; left foot flat, right foot semi-on-the-ball. OK, mainly because to opponent, it looks counterintuitive. But being lazy, I don't like to punch. If Uncle Al's solution isn't available I fall back on Aikido and wait for him hand me something to hurt him with.

b) Opponent is running toward you, probably to attempt a football
type tackle.  Now some argue that heel down is preferable, because you
get a sturdier base (in the asian styles, they call this 'drawing
power from the earth'), and you really want to impale him, rather
than strike in the usual sense.

Now I argue that (b) should have the same solution as (a), using a
relativity argument.  I.e. Force is force, momentum is momentum,
and the only that matters is relative motion; if (a) is stronger, it
should be stronger whether the opponent is standing still or in motion.

Thoughts?  Is this debate amenable to physics analysis, or only
empirically?

The fact that we aren't rigid bodies does complicate things a tad, but much of physics is about masses in motion.

  Mark L. Fergerson

.

Relevant Pages

  • Re: Punching
    ... >> You want to perform the standard right hand punch (with left foot ... > velocity between you and your opponent. ... > deal with the attacker's momentum; ... > imply not lifting your rear foot at all. ...
    (sci.physics)
  • Re: Punching
    ... >> You want to perform the standard right hand punch (with left foot ... > velocity between you and your opponent. ... > deal with the attacker's momentum; ... > imply not lifting your rear foot at all. ...
    (sci.physics)
  • Re: Punching
    ... >> You want to perform the standard right hand punch (with left foot ... > velocity between you and your opponent. ... > deal with the attacker's momentum; ... > foot at all. ...
    (sci.physics)
  • Re: Punching
    ... right foot flat, ... worried, for instance, that he'd take the punch and run into you. ... You can see the difference between force and power on the heavy bag. ... even if it doesn't swing very far. ...
    (sci.physics)
  • Re: From Black Belt
    ... Specifically, she writes that to get the punch off faster, ... suggested - the front foot comes off the floor, ... which means shifting one's COG backward. ... She said "to get the punch off faster, one should 'cheat' by shifting the weight forward, on the front foot". ...
    (rec.martial-arts)