Chris McKinley wrote:
What is the minimum amount of pressure one needs to inflict pain/damage with an empty hand?
Exactly how are you measuring that pain or that damage? Without a fairly precise answer to that question, it is impossible to answer you in any meaningful way.
Well that of course is a tricky one, I mean pain is pretty subjective unless your an experienced nurse. I was thinking along the lines of a strike that produces an involuntary and audible groan like "ORRR" or "URGHHH"
With a "push" one can be ridiculously light and send someone a fair distance at a fair speed.
This is simply factually untrue unless the person receiving the force is grossly unbalanced to begin with. Whatever the measure, it's important to note that in terms of the actual physics, the body doesn't know what is hitting it. The firehose analogy is not really optimal here since it's only applicable to a limited point. Momentum can be transferred through a stationary object (such as your hand) such that it appears that there is no movement. This applies to an extent and yet in situations in which a great deal of momentum force is transferred, the contact surface still produces a degree of force in exactly the same strength as the momentum minus that energy which is dispersed through entropy or is absorbed by the transmitting object. IOW, even though it appears not to move, it still hits really damn hard. There is physically no such thing as a situation in which a) the transmitting object appears not to move, b) the contact surface transmits only a small or negligible force, and
c) someone moves a fair distance at a fair rate of speed as a result. That is physically impossible and never occurs under any circumstances save for that the person being pushed were balancing their whole body on the head of an upright pin.[/quote]
Chris, although I would definitely agree that a person being off balance would most definitely help. It is not a deciding factor for this type of "push". The side effect of an inability to rotate/neutralize under pressure is however. It is really the stopping and lack of movement that would enable someone to perform a light pressured push. If a person is off balance and falling in a particular direction then it is necessary only to stick, adhere and follow in that direction them using an excellaration born of the maintaining the correct amount of pressure as they move away.
The same situation can happen when a person is fully balanced yet has become lifted off the ground. You lift them up, they begin to move away from you extend your joints while maintaining contact. The result is a placement of them by you to an out of range distance.
The fire hose analogy of course as you say is useful only to a point, however the point/concept I was attempting to convey was one of separating the force from the object of delivery. Even though I realize that water itself is also a substance, the differentiation of the carrier of the force and the force itself was my aim. I apologize if it came across as something else.
I also was not really speaking of the object of delivery as being stationary, just that it is making light contact with the target surface. Certainly the length of time the punch and the punched is in contact will influence the quality of force transmitted. If a very short time is executed then the shocking type force should have a strong and penetrative effect;but the question still remains (probably only in my mind
) how much or how little pressure is required to create enough of a connection for there to be an efficient transmission of force.
Chris McKinley wrote:
Now, it may feel like you're not hitting very hard if you've got the pearls lined up correctly, so to speak, but you still are if you're moving the person any significant amount and they aren't already completely unbalanced.
I once had a tap to the chest that did not move me back at all really, but did cause me to feel that my left lung was compromised. It bloody hurt too.
I have been playing with the angle of strikes and working on the optimal angle to have the strike penetrate. I have found the that 90 degrees Or perpendicular to the target just doesn't get the results that angled striking does. I am looking now to combine this with the "correct" amount of contact pressure for optimal force transference.
To true. I spent close to a week in bed with a scratched Cornia (moving the good eye caused so much pain in the bad eye) that left me blind as a result. Didn't take much pressure, effort or skill on behalf of my spar.