Punch, kicks, collisions in athletic contests

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Discussion Overview

The discussion centers on the measurement of collisions in athletic contests, specifically regarding the use of force units (pounds or kilograms) versus energy or impulse units. Participants explore the implications of these different measurement approaches in the context of sports like boxing, MMA, and football.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question why force is used to measure collisions instead of energy or impulse, suggesting that energy might be a more appropriate metric.
  • One participant argues that energy does not necessarily correlate with damage, emphasizing the importance of the time over which energy is applied, as seen in the difference between a punch and a gentle push.
  • Another participant acknowledges the role of time in collisions, proposing that even without exact values, the brief duration of impacts is significant in understanding their effects.
  • A participant with a background in electrical engineering expresses uncertainty about the topic but shares their interest in martial arts.
  • One participant notes that while energy is a good measure for impacts, it should be specified that it pertains to very short interactions, referencing how bone breakage can be modeled similarly to material testing methods.
  • Some participants suggest that the use of force in sports media may be due to its familiarity to the general public, as opposed to the more technical terms of energy or impulse.
  • Another participant clarifies that the term "force" in sports contexts refers to the impulsive force delivered, which is presented in common units for better public understanding.

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of using force versus energy or impulse as measures of collision impacts. There is no consensus on which measurement is superior, and the discussion remains unresolved.

Contextual Notes

Participants highlight the complexity of measuring impacts, noting that assumptions about time and the nature of energy transfer are critical but not fully resolved in the discussion.

corochena
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Why when a boxer, mma artist, football player, or any other athlete makes a collision such as a punch, kick or tackle we measure that using Force units (pounds or kilograms)?

Would not make more sense use Energy units or Impulse units?

I was just watching espn and they say a football player tackles with 1 ton force, what do they mean?
 
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Energy don't necessary cause damage, pain. You can spend the same amount of energy over long period of time and do no damage...eg. pushing you with my hand continuously and move you back two step or a punch that transfer the same amount of energy in 1/100 of a second. The energy is the same, but the impact is a different world. In case one, you just laugh, and the second case, you might drop!

It is the time it dicipate the same energy that make the major difference.
 
yungman, you are right, but implicitly there is a time in the punch, kick or tackle, just we don't know exactly its value, but you can imagine or estimate it

I will know that if I get punched by a 4 kg mass at 10 m/s speed I will receive 20 J energy in about 0.1 second, so even if I don't know exactly what is the time involved I know we are talking about split seconds

... but Force? maybe even pressure it is better to give an idea for a collision damage
 
I am an electrical person, not mechanical oriented. I just join in because I am into Martial Arts. I think I should quit while I am ahead and let others that are expert in this to talk to you.

Happy New Year.
 
yungman said:
Energy don't necessary cause damage, pain. You can spend the same amount of energy over long period of time and do no damage...eg. pushing you with my hand continuously and move you back two step or a punch that transfer the same amount of energy in 1/100 of a second. The energy is the same, but the impact is a different world. In case one, you just laugh, and the second case, you might drop!

It is the time it dicipate the same energy that make the major difference. [emphasis added]
...which is why the OP also said impulse.
 
corochena said:
Why when a boxer, mma artist, football player, or any other athlete makes a collision such as a punch, kick or tackle we measure that using Force units (pounds or kilograms)?

Would not make more sense use Energy units or Impulse units?

I was just watching espn and they say a football player tackles with 1 ton force, what do they mean?
Yes, when people come here, they often ask about force of an impact, but we generally try to steer them away. Energy is actually a pretty good measure as long as it is stipulated that the energy exchange is in an impact (a very short interaction). Bone breakage can be modeled very similar to how a metal bar breaks from an impact, which is measured with a Charpy tester: http://www.google.com/search?source...z=1T4ADBF_enUS311US311&q=charpy+impact+tester

Using a pendulum striking an object, you can very easily measure the energy required to break that object.

For a car crash, energy is also a good measure: the kinetic energy of the car goes into the impact.
 
So I guess the sport tv channels use Force instead of Energy or Impulse just because Force (Pounds, ton, kg) is more common term, less people would understand if they used Joules or Kg.m/s
 
they mean the amount of impulsive force delivered and in normal units so that people can understand .
 

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