Post by th0mas on Jul 12, 2012 11:31:52 GMT
I use the term kinetic in the purely scientific sense of the word as a description of the transfer of energy
I don't mean to be pedantic (and just for the record, in all of these comments I don't claim to be completely correct or "know it all" per se), but 'transfer of energy' is not what kinetic energy is. Kinetic Energy is simply the energy which something has because it is moving. Transfer is something totally different and dependent on all sorts of things (which I think the articles previously linked to explain fairly well as far as "snapping" goes).
Sorry i was just being polite before... Let me be more blunt, I believe you misunderstand how to apply the F=Ma formula and the term kinetic and potential in describing the energy states of different bodies in relation to each other.
Okay, so here's my A Level Physics answer.
F = m * a (where F is force, m is mass, and a is acceleration)
a = dv/dt (where d indicates a change, v is velocity, and t is time)
Therefore F = m* (dv/dt)
This effectively tells us that the acceleration can be thought of as the rate of change of speed. Applying this to our karate situation, the "snap" provides a mechanism to greatly reduce (as compared to letting the target slow down your fist) the time over which the acceleration occurs (in the +/- direction, it does not matter which), therefore greatly increasing the acceleration and therefore the force as per the formula.
I think.
Read more: ourshotokanstudies.proboards.com/index.cgi?board=tech&action=post&thread=925"e=7604&page=1#ixzz20P8QE7hl
F = m * a (where F is force, m is mass, and a is acceleration)
a = dv/dt (where d indicates a change, v is velocity, and t is time)
Therefore F = m* (dv/dt)
This effectively tells us that the acceleration can be thought of as the rate of change of speed. Applying this to our karate situation, the "snap" provides a mechanism to greatly reduce (as compared to letting the target slow down your fist) the time over which the acceleration occurs (in the +/- direction, it does not matter which), therefore greatly increasing the acceleration and therefore the force as per the formula.
I think.
Read more: ourshotokanstudies.proboards.com/index.cgi?board=tech&action=post&thread=925"e=7604&page=1#ixzz20P8QE7hl
ok, firstly your statement is only true if the delivery of the snap (i.e. the outward punching motion prior to connecting with the target) is increasing the final velocity of the punch compared with a different style of punch.
If when you hit the target you have not reach your maximum velocity, because you have struck too early etc, it is not an optimal strike anyway, and practicing good punching techique should ensure this irrespective of kime.
Now it is the action of the body pushing against the fist that should be applied to the F=Ma forumla. Any "braking" action to reduce the velocity of the punch will actually reduce the force that hits the target. The returning motion does not add anything to the force equation.
So you actually want the target to slow down the punch (that is how damage is applied).
I don't believe we can easily influence the dt part of the equation, this has a lot more to do with the material properties of the target you are hitting. Also some of the "macro" properties are also important (does it sit on a flexable neck structure or surrounded by wobbly fat) and what effect you wish to achieve above and beyond pure trauma damage(and this is were the Kinetic and potential energy states rear their ugly heads).
There is also an argument that you actually want to move the target if you are trying to force a knockout punch to the head. (as a result of acceleration of the brain)...but that is a whole different area.
The use of the idea of kinetic energy (KE) or momentum is wrong to be applied here I think, in that we are not trying to "move" the person in front of us with a push (i.e. give them KE/momentum) when we punch, which is what undoubtedly happens at least to some degree if you don't kime.
Read more: ourshotokanstudies.proboards.com/index.cgi?board=tech&action=post&thread=925"e=7604&page=1#ixzz20P8QE7hl
Read more: ourshotokanstudies.proboards.com/index.cgi?board=tech&action=post&thread=925"e=7604&page=1#ixzz20P8QE7hl
Ok kinetic energy (in the context in which I was using it) refers to the energy of the punch in motion, rather than the effect we force on the target. My kick whether it is a snap or a push kick has kinetic energy, the faster it is moving the higher proportion of kinetic to potentical energy it will have. As the kick transitions over time from initiation to striking, the proportion of potential to kinetic will change. In fact a snap kick wants to maximise the kinetic energy at the point of contact whilst a push kick wants to keep a degree of potential energy in reserve to push the target after the inital contact. In practical terms, for Maegeri, this is usually achieved through the timing the engagement of the hip.
Finally let me be absolutely clear...I am enjoying the debate and appreciate that you have bothered to put in the time.. but I think you are wrong! ... game on