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If "3 pounds of pressure is sufficient to break an extended knee", then...

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    If "3 pounds of pressure is sufficient to break an extended knee", then...

    how do you explain this?!?!?:



    The quote was from some shitty krotty website on another thread. The whole "X lbs of pressure to break Y" is a fractally wrong martial arts phrase that I can't stand, for any number of reasons.
    -pressure isn't expressed in pounds

    -when "force" is used instead, that isn't measured in pounds either

    -they always say its like less than 10 lbs. I could balance a 10 lb weight pretty much anywhere (trachea, etc) and not have structural failure.

    -its often used in conjunction with explanations for why board breaking is somehow relevant to punching people, and that's apples and oranges

    -someone replied that it would've broken my knee if I lifted it up and dropped it, or used the 5lb weight to strike the joint. Neither of those describe 5 lbs of pressure or weight. I could just as easily say that I can kill you with seven grams of force if I shoot it out of a gun.

    #2
    Originally posted by Permalost View Post
    how do you explain this?!?!?:
    Your chi is strong.







    Also: https://magazine.fighttimes.com/the-knee/

    Comment


      #3
      Originally posted by Permalost View Post
      -when "force" is used instead, that isn't measured in pounds either
      Actually force can be measured as pounds (lb) in certain systems. A pound can measure mass OR force.

      Technically when using lbs to represent force, "pound" is really shorthand for "pound-force" or lbf.

      it's exactly what it sounds like, the gravitational force of a pound of something.

      The weight on your leg has 5 lbs of (pound-)mass , and 5 lbs of (pound-)force.

      Just for reference, 1 lbf = 4.448222 N (on Earth).
      Last edited by W. Rabbit; 9/17/2015 11:38am, .

      Comment


        #4
        Anyway, this "3 pounds of pressure is sufficient to break an extended knee" is bs. No nerd talk needed.

        Comment


          #5
          Originally posted by Permalost View Post
          how do you explain this?!?!?:



          The quote was from some shitty krotty website on another thread. The whole "X lbs of pressure to break Y" is a fractally wrong martial arts phrase that I can't stand, for any number of reasons.
          -pressure isn't expressed in pounds

          -when "force" is used instead, that isn't measured in pounds either

          -they always say its like less than 10 lbs. I could balance a 10 lb weight pretty much anywhere (trachea, etc) and not have structural failure.

          -its often used in conjunction with explanations for why board breaking is somehow relevant to punching people, and that's apples and oranges

          -someone replied that it would've broken my knee if I lifted it up and dropped it, or used the 5lb weight to strike the joint. Neither of those describe 5 lbs of pressure or weight. I could just as easily say that I can kill you with seven grams of force if I shoot it out of a gun.
          Goddamn! Such an amazing fucking knee in that picture! 5 pounds. Lawd! You must be like Wolverine or Spiderman or something.

          Comment


            #6
            Context:

            The added benefit of wood breaking is that it teaches you to “snap” the strikes because while bags are pushed by the strike, wood will not break unless the strike is delivered with speed and a “snap”. Finally, one’s ability to defend himself is generally preceded by confidence or belief that he/she can succeed. Wood breaking can help one to understand that he has the power to inflict damage on an attacker and thus an additional sense of confidence in his ability. Breaking one piece of wood requires the same force as breaking a rib or an attacker’s knee. In fact, 3 pounds of pressure is sufficient to break an extended knee.

            When one break’s a piece of wood he realizes that he can truly stand up and defend himself. Therefore, when a bully appears one no longer has to feel like an unprotected victim. He will have renewed confidence in his abilities, and that will be obvious in everything he does! Resistance to peer pressure will accompany improvement in self-esteem. Instead of simply following the crowd, he can follow his beliefs in what is right and what is wrong. Wood breaking provides a feeling of confidence, empowerment and accomplishment! One will be filled with excitement and the feeling he can accomplish and do just about anything!
            He is bullshitting about force and pressure while in the process of bullshitting about breaking wood.
            Last edited by W. Rabbit; 9/17/2015 11:52am, .

            Comment


              #7
              Originally posted by Devil View Post
              Goddamn! Such an amazing fucking knee in that picture! 5 pounds. Lawd! You must be like Wolverine or Spiderman or something.
              Someone on FB posted "I was taught it was 20 lbs", so I posted this mindblowing photo:

              Comment


                #8

                Comment


                  #9
                  The "breaking a board is the equivalent of breaking a rib" bullshit line was also featured in Martial Arts for Dummies.

                  http://www.amazon.com/Martial-Arts-D.../dp/0764553585

                  Comment


                    #10
                    My karate school said 14 pounds to break the collarbone. This was helpful because it was so plainly false, thereby giving me something concretely wrong to start from when I started questioning things. Watching Kyokushin tournament videos helped. Their collarbones are taking a beating. There was a clear line in my critical thinking from there to "why don't MMA fighters knees explode when they take leg kicks" to quitting and training judo and so on.

                    Comment


                      #11
                      Some good stats here: http://www.livescience.com/6040-brut...ans-punch.html

                      A cubic inch of bone can in principle bear a load of 19,000 lbs.
                      When it comes to unleashing force quickly, Bir and her colleagues investigated boxers and found they could generate up to 5,000 newtons of force with a punch, more than that exerted down by a half-ton on Earth's surface.

                      When it comes to kicks, "they can obviously generate more force, since there's more body mass behind it," Bir said. After looking at kicks from several different fighting styles, they found that experts could generate up to 9,000 newtons with them, equal to roughly a ton of force.

                      A quick, sharp blow that delivers some 3,300 newtons of force has a 25 percent chance of cracking an average person's rib, she said. It takes more force to fracture the femur, Bir noted — maybe some 4,000 newtons— since that long thighbone is meant to support the body.
                      So roughly using these numbers a 4kN - 5kN strike could produce about 900-1100 lbs (force). A 9kN kick would be about 2,000 lbs (force). Both might have enough force to fracture bone, but it would depend on the exact surface area, acceleration, timing etc.

                      Interesting article at Slate.com, mentions some real-world cases of breaks...couple orders of magnitude larger than single digits..makes sense. Of course that is 200+ lbs at zero velocity, and 200 lbs is not a lot.

                      The amount of force required to produce these injuries depends on a number of factors, including the location of the impact, the thickness of the soft tissue around the tibia, the condition of the bone, and the area across which the force is spread. As a rough estimate, it would take 218 pounds of pressure to produce a tibial fracture in a healthy adult using a hammer. You could decrease the force requirement by choosing a tool with less surface area, such as a hatchet—then again, you'd be increasing the risk of soft tissue damage and significant blood loss. In any case, it might be hard to generate that amount of force with your knee and ankle strapped down, so you may need the help of a friend.

                      There have been some reports of people breaking their own tibias without help. In 2008, an Australian kayaker who had become trapped in his boat by a fallen log leveraged his body weight (supported by the tremendous force of the current) to snap his tibia against the rim of the boat's cockpit. The break enabled his trapped leg to collapse so he could escape the boat.
                      http://www.slate.com/articles/news_a...eak_a_leg.html
                      Last edited by W. Rabbit; 9/17/2015 3:49pm, .

                      Comment


                        #12
                        Board breaking when it comes to Okinawan Arts like Karate and its Japanese and Korean offshoots (Shotokan & TKD) was always a parlor trick to impress during demonstration and was never an actual training method. All this bullshit was added by no sparring and point sparring schools to make themselves feel badass without have to prove it against an resisting human being.

                        Comment


                          #13
                          Originally posted by <plasma> View Post
                          Board breaking when it comes to Okinawan Arts like Karate and its Japanese and Korean offshoots (Shotokan & TKD) was always a parlor trick to impress during demonstration and was never an actual training method.
                          I think, based on very little actual research, that parlor tricks and physical feats were a big part of being a Chinese or Okinawan martial artist. Strongman and gymnastic feats are impressive and have some validity as part of training.

                          Comment


                            #14
                            Originally posted by W. Rabbit View Post
                            Context:



                            He is bullshitting about force and pressure while in the process of bullshitting about breaking wood.
                            All while proudly bragging about the false confidence he imparts to his students.

                            Comment


                              #15
                              Originally posted by BackFistMonkey View Post
                              All while proudly bragging about the false confidence he imparts to his students.
                              "Finally, one’s ability to defend himself is generally preceded by confidence or belief that he/she can succeed".
                              I think John DuPont/Steve Carell said something similar in Foxcatcher.

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