Fighting shaped human hands

December 19, 2012

The human hand is a finely tuned piece of equipment that is capable of remarkable dexterity: creating art, performing music and manipulating tools. Yet David Carrier from the University of Utah, USA, suggests that the human hand may have also evolved its distinctive proportions for a less enlightened reason: for use as a weapon. Carrier and colleague Michael Morgan publish their theory that human hands evolved their square palms and long thumb to stabilise the fist and produce a compact club for use in combat in The Journal of Experimental Biology at

Carrier recalls that the idea occurred to him during an impassioned discussion with fellow biomechanic Frank Fish about sperm whales. Explaining that he had published a paper suggesting that the whales might use their spermaceti organs as battering rams, Carrier says 'Frank didn't buy the argument and at one point he raised his fist and said, "I can hit you in the face with this, but that is not what it evolved for."' A light went on in Carrier's head. Sure, the human hand evolved for dexterity, but he adds, 'You could manipulate the proportions of a chimp hand in ways that would enhance manual dexterity, but they would not necessarily end up with the proportions that we have.' Maybe there was more to Fish's challenge than met the eye.

According to Carrier and Morgan, modern chimpanzees have long palms and fingers with a short thumb, while the human palm and fingers are much shorter and the thumb longer and stronger. Carrier explains that this squat arrangement allows us to clench our hand into a fist when we fold the thumb across the fingertips however, chimp fingers form an open doughnut shape when curled. Could the tightly packed human fist provide internal support - buttressing - to the digits to protect them from damage during combat? In addition, Carrier wondered whether curling the fingers into a fist could allow punching men to deliver a more powerful blow (increase the peak force of an impact) than slapping with the open hand. Carrier and Morgan decided to find out whether hands are more effective when balled into a fist or wielded in a slap.

'Fortunately, Michael had a lot of experience with martial arts and he knew people who were willing to serve as subjects', Carrier recalls. Asking the athletes to thump a punchbag with their hands in a range of shapes (from open-handed slaps to closed fists) using various delivery styles (over arm, sideways and head on), Morgan and Carrier measured the force of each impact. However, they were surprised to see that the punch did not deliver more force per blow. 'In terms of the peak forces or the impulse, it did not matter whether the subjects were hitting with a clenched fist or open palm', Carrier says.

Next the duo tested whether buttressing the hand by curling the fingers and thumb stiffens the structure. They asked the martial arts experts to roll their hands into variations of the fist shape - two with the thumb extended sideways - and then push the first joint of the index finger against a force transducer to measure the rigidity of the knuckle joint in the presence and absence of the buttressing thumb. Impressively, the knuckle joint was four times more rigid when supported by the thumb. And when the duo measured the amount of force that the athletes could deliver through the fist surface of the index and middle fingers, they found that the presence of the buttressing thumb doubled the delivered force by transmitting it to the wrist through the metacarpals (palm bones) of the thumb and the index finger.

So our short, square hands are perfectly proportioned to stiffen our fists for use as weapons and allow us - well, males predominantly - to deliver powerful punches without incurring injuries.

REFERENCE: Morgan, M. H. and Carrier, D. R. (2013). Protective buttressing of the human fist and the evolution of hominin hands. J. Exp. Biol. 216, 236-244.

This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT


The Company of Biologists

Related Martial Arts Articles from Brightsurf:

Which is more creative, the arts or the sciences?
International expert in creativity and innovation, UniSA's Professor David Cropley, is calling for Australian schools and universities to increase their emphasis on teaching creativity, as new research shows it is a core competency across all disciplines and critical for ensuring future job success.

Plagiarism and inclusivity shown in new study into the arts, humanities and social sciences
A new study looking at the issues arising in publication ethics that journal editors face within the arts, humanities and social sciences has highlighted that detecting plagiarism in papers submitted to a journal is the most serious issue they tackle, something which over half of editors reported encountering.

Arts and medicine: clarifying history, lessons for today from Peter Neubauer's twins study
This Arts and Medicine feature reviews 'Three Identical Strangers' and 'The Twinning Reaction,' two documentaries telling the story of identical twins and triplets adopted as infants into separate families who were unknowing participants in a two-decade nature vs. nurture study of child development beginning in 1960.

Arts education can provide creative counter narratives against hate speech
Hate, as an emotion, is not an efficient response to ideological hate speech.

Taking arts classes leads to better academic performance, Mason research shows
A new study from the George Mason University Arts Research Center and published in the journal Psychology of Aesthetics, Creativity, and the Arts found a link between arts elective courses in music, dance, visual art and drama, and better grades in middle school.

Singing for science: How the arts can help students who struggle most
Incorporating the arts -- rapping, dancing, drawing -- into science lessons can help low-achieving students retain more knowledge and possibly help students of all ability levels be more creative in their learning, finds a new study by Johns Hopkins University.

Arts and culture could help Finnish schools reach new heights of excellence
Finland has one of the best education systems in the world.

Arts and humanities in medical school promote empathy and inoculate against burnout
Medical students who spend more time engaging in the arts may also be bolstering the qualities that improve their bedside manner with patients, according to new research from Tulane and Thomas Jefferson universities.

Study: Rate and risk of head injury in mixed martial arts remain unknown
The rate and potential risk of traumatic brain injury in mixed martial arts remain unknown due to lack of regulation and protocols surrounding these injuries, according to a new study.

Call for arts to keep up with Asia
A James Cook University researcher says Australia lacks a proper strategy for developing the arts sector, as Asian nations pour money into developing their cultural power.

Read More: Martial Arts News and Martial Arts Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to