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    Fighting may have shaped the evolution of the human hand, according to a new study by a US team

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    genetic judoka

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    Fighting may have shaped the evolution of the human hand, according to a new study by a US team

    Post by genetic judoka on Sat May 25, 2013 4:56 am

    Fighting may have shaped the evolution of the human hand, according to a new study by a US team.

    Fighting may have shaped the evolution of the human hand, according to a new study by a US team.

    The University of Utah researchers used instruments to measure the forces and acceleration when martial artists hit a punch bag.

    They found that the structure of the fist provides support that increases the ability of the knuckles to transmit “punching” force.

    Details have been published in the Journal of Experimental Biology.

    “We asked the question: ‘can you strike harder with a fist than with an open palm?’,” co-author David Carrier told BBC News.

    “We were surprised because the fist strikes were not more forceful than the strikes with the palm. In terms of the work on the bag there is really no difference.”

    Of course, the surface that strikes the target with a fist is smaller, so there is more stress from a fist strike.

    “The force per area is higher in a fist strike and that is what causes localised tissue damage,” said Prof Carrier.

    “There is a performance advantage in that regard. But the real focus of the study was whether the proportions of the human hand allow buttressing (support).”

    The team found that making a clenched fist did indeed provide protective buttressing for the delicate bones of the hand. Making a fist increased the stiffness of the second meta-carpo-phalangeal, or MCP, joint (these joints are the knuckles visible when the hand is clenched as a fist) by a factor of four.

    It also doubled the ability of the proximal phalanges (the bones of the fingers that articulate with the MCP joints) to transmit a punching force.
    Dual use

    In their paper, Prof Carrier and Michael H Morgan from the University of Utah’s school of medicine, point out that the human hand has also been shaped by the need for manual dexterity. But they say that a number of different hand proportions are compatible with an enhanced ability to manipulate objects.
    The bones of the hand line up into a strong, buttressed structure in a fist

    “There may, however, be only one set of skeletal proportions that allows the hand to function both as a mechanism for precise manipulation and as a club for striking,” the researchers write.

    “Ultimately, the evolutionary significance of the human hand may lie in its remarkable ability to serve two seemingly incompatible, but intrinsically human, functions.”

    Our closest relatives, chimpanzees and bonobos do not generally form fists, and the researchers think they are unable to: when a chimp curls up its fingers it forms a doughnut shape.

    Prof Carrier commented: “The question for me is ‘why wasn’t this discussed 30, 40 years ago.’ As far as I know it isn’t in the literature.”

    Asked whether the idea that aggression may have played a key role in shaping the human body might previously have been unpalatable to researchers, Prof Carrier explained: “I think we’re more in that situation now than we were in the past.

    “I think there is a lot of resistance, maybe more so among academics than people in general – resistance to the idea that, at some level humans are by nature aggressive animals. I actually think that attitude, and the people who have tried to make the case that we don’t have a nature – those people have not served us well.

    “I think we would be better off if we faced the reality that we have these strong emotions and sometimes they prime us to behave in violent ways. I think if we acknowledged that we’d be better able to prevent violence in future.”


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    Cichorei Kano

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    Re: Fighting may have shaped the evolution of the human hand, according to a new study by a US team

    Post by Cichorei Kano on Sat May 25, 2013 7:46 am

    There's lots of stuff one can research. The Korean researchers Seo et al in 2010 published a study in the Korean Journal of Urology wondering if the ration of your index finger to ring finger would be a reliable predictor of your semen quality ...

    Don't believe me ? The reference is: Seo H, Kim KY, Rho J. Is the Index Finger and Ring Finger Ratio (2D:4D) Reliable Predictor of Semen Quality? Korean J Urol. 2010; 51(3): 208-211.

    Their conclusion was ... it wasn't. That conclusion wasn't reached though before the necessary grant money was spent ...


    At least the Dutch do some more practical applicable work and showed that women who have higher finger sensitivity are more active in sexual encounters with partners ... Yup: Brody S, Fischer AH, Hess U. Women's finger sensitivity correlates with partnered sexual behavior but not solitary masturbation frequencies. J Sex Marital Ther. 2008; 34(4): 343-352.

    As to the new study, I went to find it. The full reference is: Morgan MH, Carrier DR. Protective buttressing of the human fist and the evolution of hominin hands. J Exp Biol. 2013 Jan 15;216(Pt 2): 236-44.

    Here's the abstract:

    The derived proportions of the human hand may provide supportive buttressing that protects the hand from injury when striking with a fist. Flexion of digits 2-5 results in buttressing of the pads of the distal phalanges against the central palm and the palmar pads of the proximal phalanges. Additionally, adduction of the thenar eminence to abut the dorsal surface of the distal phalanges of digits 2 and 3 locks these digits into a solid configuration that may allow a transfer of energy through the thenar eminence to the wrist. To test the hypothesis of a performance advantage, we measured: (1) the forces and rate of change of acceleration (jerk) from maximum effort strikes of subjects striking with a fist and an open hand; (2) the static stiffness of the second metacarpo-phalangeal (MCP) joint in buttressed and unbuttressed fist postures; and (3) static force transfer from digits 2 and 3 to digit 1 also in buttressed and unbuttressed fist postures. We found that peak forces, force impulses and peak jerk did not differ between the closed fist and open palm strikes. However, the structure of the human fist provides buttressing that increases the stiffness of the second MCP joint by fourfold and, as a result of force transfer through the thenar eminence, more than doubles the ability of the proximal phalanges to transmit 'punching' force. Thus, the proportions of the human hand provide a performance advantage when striking with a fist. We propose that the derived proportions of hominin hands reflect, in part, sexual selection to improve fighting performance.

    I can't write much about it since as this isn't the right medium to do so, but there seems to be somewhat of a 'jump' between the results they found, and the conclusions they draw. More precisely, they show the biomechanical efficiency of the fist as compared to the open hand with regard to certain actions. Fair enough, but that does not say much about the reason. Did our hands evolve that way so we could better fight ? That is strange. Why did our mouths not evolve as in a tiger or alligator so we could better bite during fighting ? So the monkeys apparently do not have the same hand tactility ? OK, but is this evolutionary ? Why ? Because monkeys don't like to fight ? Or because they do, but not in the same way as humans ? There are so many questions and options, that it is quite a jump to go from one to the other. The use of fists in martial arts is documented way before the Japanese martial arts existed, such as notably in the classic Greek Olympics pankration and pale, etc. But that is still very young when compared with the whole evolution of man. Why did our feet not evolve in a way we could do as much with them like monkeys can ? That would be useful too for fighting. Again one could come with strange arguments and prove for example that it is possible to kick a ball better the way our feet are now, and that therefore the way our feet are, are an evolutionary result to enable us to better play soccer. I mean, what evidence is that the way we can make a fist is not rather the result than the origin of the problem ? I do not want to sound disrespectful. I know how much work there goes into doing research, but those are some of the basic and obvious questions which many martial artists might have when hearing about or reading the newspaper


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    seatea

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    Re: Fighting may have shaped the evolution of the human hand, according to a new study by a US team

    Post by seatea on Sat May 25, 2013 9:07 am

    Fighting may well of had an effect on our evolution but I believe it would shown itself in our ability to conceive and make weapons.

    Broken hand bones are some of the most common injuries in MMA despite having the added protection of wrapping and gloves. Fists are by and large poor weapons.
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    Quicksilver

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    Re: Fighting may have shaped the evolution of the human hand, according to a new study by a US team

    Post by Quicksilver on Sat May 25, 2013 11:08 am

    genetic judoka wrote:Fighting may have shaped the evolution of the human hand, according to a new study by a US team.

    Fighting may have shaped the evolution of the human hand, according to a new study by a US team.

    The University of Utah researchers used instruments to measure the forces and acceleration when martial artists hit a punch bag.

    They found that the structure of the fist provides support that increases the ability of the knuckles to transmit “punching” force.

    Details have been published in the Journal of Experimental Biology.

    “We asked the question: ‘can you strike harder with a fist than with an open palm?’,” co-author David Carrier told BBC News.

    “We were surprised because the fist strikes were not more forceful than the strikes with the palm. In terms of the work on the bag there is really no difference.”

    Of course, the surface that strikes the target with a fist is smaller, so there is more stress from a fist strike.

    “The force per area is higher in a fist strike and that is what causes localised tissue damage,” said Prof Carrier.

    “There is a performance advantage in that regard. But the real focus of the study was whether the proportions of the human hand allow buttressing (support).”

    The team found that making a clenched fist did indeed provide protective buttressing for the delicate bones of the hand. Making a fist increased the stiffness of the second meta-carpo-phalangeal, or MCP, joint (these joints are the knuckles visible when the hand is clenched as a fist) by a factor of four.

    It also doubled the ability of the proximal phalanges (the bones of the fingers that articulate with the MCP joints) to transmit a punching force.
    Dual use

    In their paper, Prof Carrier and Michael H Morgan from the University of Utah’s school of medicine, point out that the human hand has also been shaped by the need for manual dexterity. But they say that a number of different hand proportions are compatible with an enhanced ability to manipulate objects.
    The bones of the hand line up into a strong, buttressed structure in a fist

    “There may, however, be only one set of skeletal proportions that allows the hand to function both as a mechanism for precise manipulation and as a club for striking,” the researchers write.

    “Ultimately, the evolutionary significance of the human hand may lie in its remarkable ability to serve two seemingly incompatible, but intrinsically human, functions.”

    Our closest relatives, chimpanzees and bonobos do not generally form fists, and the researchers think they are unable to: when a chimp curls up its fingers it forms a doughnut shape.

    Prof Carrier commented: “The question for me is ‘why wasn’t this discussed 30, 40 years ago.’ As far as I know it isn’t in the literature.”

    Asked whether the idea that aggression may have played a key role in shaping the human body might previously have been unpalatable to researchers, Prof Carrier explained: “I think we’re more in that situation now than we were in the past.

    “I think there is a lot of resistance, maybe more so among academics than people in general – resistance to the idea that, at some level humans are by nature aggressive animals. I actually think that attitude, and the people who have tried to make the case that we don’t have a nature – those people have not served us well.

    “I think we would be better off if we faced the reality that we have these strong emotions and sometimes they prime us to behave in violent ways. I think if we acknowledged that we’d be better able to prevent violence in future.”

    Interesting, but I would say that supporting the argument that there are biomechanical advantages to striking with a closed fist (which this has done) and supporting the argument that the structure of the hand evolved specifically for this reason- whether by natural or sexual selection- are not quite the same thing, and I'm not convinced that it has adequately adressed the latter. Finding a relationship does not in and of itself confirm the nature of it.

    Also, as a comment, striking a solid object with the palm of the hand with force may be less effective than using a closed fist, but from personal experiemce it is also considerably less likely to be very uncomfortable.

    But like I said, interesting.

    EDIT- I saw the posted abstract, would still pose the same queries.


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