Re: Why Humans Walk On Two Legs?

July 22, 2007

My reaction to this is " they are wasting time and money studying this? "

I cannot see that this has true bearing on the locomotion of modern man.

Knuckle dragging in men now being merely a fashion statement or an attitude, not

a literal thing? And if they had come about with a conclusion that traveling

bent forward on knuckles was far more efficient in humans, would we start to see

this in competitions?

There's so many things to study in the world, why this one.

The Phantom

aka Schaefer, CMT, CSCS, competing powerlifter

Denver, Colorado, USA

======================================

-------------- Original message --------------

The below may be of interest:

Why Humans Walk On Two Legs

http://www.sciencedaily.com/releases/2007/07/070720111226.htm

Science Daily — A team of anthropologists that studied chimpanzees

trained to use treadmills has gathered new evidence suggesting that

our earliest apelike ancestors started walking on two legs because it

required less energy than getting around on all fours.

" When our earliest ancestors started walking on two legs, they took

the first steps toward becoming human, " said lead researcher

Sockol of UC . " Our findings help answer why. "

" This is the first time anyone has succeeded in studying energetics

and biomechanics in adult chimps, " said Sockol, who worked for two

years to find an animal trainer willing to coax adult chimps to walk

on two legs and to " knucklewalk " on all fours on the sort of

treadmill found in most gyms. The five chimps also wore face masks

used to help the researchers measure oxygen consumption.

While the chimps worked out, the scientists collected metabolic,

kinematic and kinetic data that allowed them to calculate which

method of locomotion used less energy and why. The team gathered the

same information for four adult humans walking on a treadmill.

The researchers found that human walking used about 75 percent less

energy and burned 75 percent fewer calories than quadrupedal and

bipedal walking in chimpanzees. They also found that for some but not

all of the chimps, walking on two legs was no more costly than

knucklewalking.

" We were prepared to find that all of the chimps used more energy

walking on two legs -- but that finding wouldn't have been as

interesting, " Sockol said. " What we found was much more telling. For

three chimps, bipedalism was more expensive, but for the other two

chimps, this wasn't the case. One expended about the same energy

walking on two legs as on four. The other used less energy walking

upright. "

These two chimps had different gaits and anatomy than their

knucklewalking peers. And when the researchers examined the early

hominid fossil record, they found evidence of these traits – skeletal

characteristics of the hip and hind limb that allow for greater

extension of the hind limb -- in some early bipeds.

Taken together, the findings provide support for the hypothesis that

anatomical differences affecting gait existed among our earliest

apelike ancestors, and that these differences provided the genetic

variation natural selection could act on when changes in the

environment gave bipeds an advantage over quadrupeds.

Fossil and molecular evidence suggests the earliest ancestors of the

human family lived in forested areas in equatorial Africa in the late

Miocene era some 8 to 10 million years ago, when changes in climate

may have increased the distance between food patches. That would have

forced early hominids to travel longer distances on the ground and

favored those who could cover more ground using less energy.

" This isn't the complete answer, " Sockol said. " But it's a good piece

of a puzzle humans have always wondered about: How and why did we

become human? And why do we alone walk on two legs? "

Sockol, a doctoral candidate in anthropology, has been pursuing his

research for four years as part of his dissertation. He conducted the

research at UC and at a private animal refuge and training

facility in Northern California with colleagues Herman Pontzer of

Washington University in St. Louis and Raichlen of the

University of Arizona.

His work was featured in the July 2006 issue of National Geographic.

A video of the chimpanzees walking and knucklewalking on the

treadmill can be seen at

http://www7.nationalgeographic.com/ngm/0607/feature5/multimedia.html

The research appears in the online early edition of the Proceedings

of the National Academy of Sciences and in the July 24 print edition.

========================

July 23, 2007

Hi !

There are many studies that, at least on the surface, seem far more bizarre

than the recent bipedal research with " Jack. " I recall shaking my head when

I first saw a photo of researchers walking alongside an elephant who was

fitted with a large bag-like structure for measuring oxygen consumption.

But something significant for humans always emerges from such studies For

example, the findings from the " Jack " research provided support for the

hypothesis that " anatomical differences affecting gait existed among our

earliers

apelike ancestors, and that these differences provided the genetic variation

natural selection could act on when changes in the environment gave bipeds an

advantage over quadrupeds. "

Why is this important ? When some apes reveal that they actually reduce

metabolic cost through bipedal locomotion, this further challenges the

assumption, surprisingly held by many, that we all have the same genetically

coded

'structural symmetry,' and that we can easily determine what are the most

cost-efficient movement patterns in any species. From my perspective, a

penguin's movements appear highly inefficient. Thank goodness, I can't

'change' a

penguins waddle to fit my view of good movment, but I used to do that all the

time with the athletes I coached.

And this explains, in part, why those working in the field of human

locomotion have noted that making corrrections to what we perceive as

mechanics

errors might not always be a good idea. Trying to fit all athletes to a

specific style or technique ignores that fact that a particular athlete's

movements

may be the way he or she needs to translate the skill of the sport based

upon unique asymmetries, attachments points, etc. that we don't even know

exist. In this regard, the perceived 'aberrant movements' may be corrections

in

themselves. Mel often alluded to this same point.

We took my daughter's chihuahua to the vet recently. The vet had a new

X-ray machine that he wanted to try it out. The x-rays revealed that Cody's

left

hip does not rest in the socket like the right one. It looked like an injury

to me.

I asked the vet: " Is it something he might have done jumping from a couch

or chair? "

The vet's response: " No, I think we'll blame his grandmother for this. "

In other words, it's a genetic issue that means Cody needs to 'translate'

running a little differently.

Ken Jakalski

Lisle HS

Lisle, Illinois

July 23, 2007

Krista's recent post gives us a good insight on the value of what at first

strikes many of us frivolous research with little real world application.

The discussion reminds me of the flap over Tom McMahon's research on

" Groucho Running. " Some felt that any study relating human locomotion to the

movements of comedian proved just how riduculous much of research really is..

However, McMahon saw the technique of running with enhanced knee flexion being

similar to the famous 'Groucho walk,' and it proved to be an insightful

analogy.

McMahon's work determined that Groucho running reduces the amount of shock

transmitted through the body during footstrike by as much as 80 per cent.

However, there was a trade-off with this shock reduction: the oxygen cost

(economy) of running at a particular speed shoots up by about 50% during the

Groucho gait.

The Groucho concept is used quite frequently in locomotion now, and more

recently in relation to research on how elephants 'run.'

The sad thing is that a whole generation of kids might grow up not knowing

who Groucho Marx was!

Ken Jakalski

Lisle HS

Lisle, Illinois

July 23, 2007

On the issue of apes and chimps:

This is certainly off-topic, but fun nevethleless.

Many years ago, one of my favorite undergrad professors liked to challenge

the efficacy of giving students multiple choice exams.

He mentioned something he referred to as the " Chimpanzee Principle. "

If you gave students a fifty point multiple choice test with at least three

foils (A-B-C-D), and had one student 'take' the exam again by simply filling

in the bubbles randomely (hence, the chimp) he believed at least one or

more of our students would score below the randomely filled out answer sheet.

In other words, the 'chimp' would earn a higher score.

We all laughed, but I actually tried it during my first ten years of

teaching--when I still believed in multiple choice tests. In non-honors

classes of

twenty-five or more students, I would have between one and three students

actually score lower on my exams than 'the chimp. "

Now, I'm sure there's probably some statistical explanation for why 'the

chimp' not reading any questions would score higher than those who actually

read

the questions, but I came to the conclusion that I was structuring

instruments that really weren't accurately assessing what kids learned.

Every aseessment response that I now expect from students is in complete

sentence, 'short-answer insight' form.

Ken Jakalski

Lisle HS

Lisle, Illinois

July 23, 2007

Often studies that do not appear to have immediate applications

nevertheless unveil particular principles that can then be used in

other research. So often, people want to rush to the applications and

the concrete. But it is often the principles of things that we use to

drive innovation, adaptation, and modification.

I can think of many future applications for understanding principles

of human locomotion. F'rinstance:

Deciding which elements of gait are fundamental and which can/should

be changed can be used in rehab and physical therapy. Understanding

how bodies conserve energy during movement can be used in athletic

training. The structural basis for locomotion in semi-quadrupeds and

bipeds can be applied to robotics.

The flight of dragonflies and maple seedlings applies to helicopters;

the structure of a bird's wing gives us the airplane; Velcro comes

from burr hooks. As Leonardo da Vinci proposed, all " technologies "

already exist in nature; all we need to do is carefully observe them

and figure out how to reconstruct them.

Best wishes,

Krista -Dixon

Toronto, ON

kristascottdixon@...

July 25, 2007

In a message dated 7/25/2007 8:20:10 AM Central Daylight Time,

Carruthersjam@... writes:

Human buttocks " are huge, " says Bramble. " Have you ever looked at

an ape? They have no buns. "

****

We used this research as an epigram for our Lisle Lions " Mane Event " cross

country invitational t-shirts two years ago:

â€œRunning seems to be the only reason that we have prominent buttocks.â€

-- Dr. Lieberman, Harvard University

Ken Jakalski

Lisle HS

Lisle, Illinois

July 25, 2007

Here are three alternative explanations for why primates decided to

walk on two instead of four legs. They all relate to a period in

primate/hominid evolution when primates descended from the jungle and

trees to the east African savannah, probably prior to about 5-6

million years ago. It's all based on standard evolutionary theory -

survival advantage etc.

1. The aquatic ape theory. Wading in swamps and river shallows to

catch/collect food obviously favored upright walking.

2. Standing on two legs provided an advantage in looking out for

predators and enemies - long grass etc.

3. Standing/walking upright allowed browsing on low-hanging fruit

without climbing.

Just a few ideas I've collected over the years.

As to whether early hominids/humans were sprinters or long distance

runners. . . I'd say both -- with endurance the bread and butter

activity and fast intervals a predator and tribal conflict survival

tool.

Gympie, Australia

>

> The below may be of interest:

>

> Why Humans Walk On Two Legs

> http://www.sciencedaily.com/releases/2007/07/070720111226.htm

>

> Science Daily — A team of anthropologists that studied chimpanzees

> trained to use treadmills has gathered new evidence suggesting that

> our earliest apelike ancestors started walking on two legs because

it

> required less energy than getting around on all fours.

>

> " When our earliest ancestors started walking on two legs, they took

> the first steps toward becoming human, " said lead researcher

> Sockol of UC . " Our findings help answer why. "

>

> " This is the first time anyone has succeeded in studying energetics

> and biomechanics in adult chimps, " said Sockol, who worked for two

> years to find an animal trainer willing to coax adult chimps to

walk

> on two legs and to " knucklewalk " on all fours on the sort of

> treadmill found in most gyms. The five chimps also wore face masks

> used to help the researchers measure oxygen consumption.

>

> While the chimps worked out, the scientists collected metabolic,

> kinematic and kinetic data that allowed them to calculate which

> method of locomotion used less energy and why. The team gathered

the

> same information for four adult humans walking on a treadmill.

> The researchers found that human walking used about 75 percent less

> energy and burned 75 percent fewer calories than quadrupedal and

> bipedal walking in chimpanzees. They also found that for some but

not

> all of the chimps, walking on two legs was no more costly than

> knucklewalking.

>

> " We were prepared to find that all of the chimps used more energy

> walking on two legs -- but that finding wouldn't have been as

> interesting, " Sockol said. " What we found was much more telling.

For

> three chimps, bipedalism was more expensive, but for the other two

> chimps, this wasn't the case. One expended about the same energy

> walking on two legs as on four. The other used less energy walking

> upright. "

>

> These two chimps had different gaits and anatomy than their

> knucklewalking peers. And when the researchers examined the early

> hominid fossil record, they found evidence of these traits –

skeletal

> characteristics of the hip and hind limb that allow for greater

> extension of the hind limb -- in some early bipeds.

>

> Taken together, the findings provide support for the hypothesis

that

> anatomical differences affecting gait existed among our earliest

> apelike ancestors, and that these differences provided the genetic

> variation natural selection could act on when changes in the

> environment gave bipeds an advantage over quadrupeds.

>

> Fossil and molecular evidence suggests the earliest ancestors of

the

> human family lived in forested areas in equatorial Africa in the

late

> Miocene era some 8 to 10 million years ago, when changes in climate

> may have increased the distance between food patches. That would

have

> forced early hominids to travel longer distances on the ground and

> favored those who could cover more ground using less energy.

>

> " This isn't the complete answer, " Sockol said. " But it's a good

piece

> of a puzzle humans have always wondered about: How and why did we

> become human? And why do we alone walk on two legs? "

> Sockol, a doctoral candidate in anthropology, has been pursuing his

> research for four years as part of his dissertation. He conducted

the

> research at UC and at a private animal refuge and training

> facility in Northern California with colleagues Herman Pontzer of

> Washington University in St. Louis and Raichlen of the

> University of Arizona.

>

> His work was featured in the July 2006 issue of National

Geographic.

> A video of the chimpanzees walking and knucklewalking on the

> treadmill can be seen at

>

http://www7.nationalgeographic.com/ngm/0607/feature5/multimedia.html

> The research appears in the online early edition of the Proceedings

> of the National Academy of Sciences and in the July 24 print

edition.

>

> ========================

> Carruthers

> Wakefield, UK

>

July 25, 2007

>

> Here are three alternative explanations for why primates decided to

> walk on two instead of four legs. They all relate to a period in

> primate/hominid evolution when primates descended from the jungle

and

> trees to the east African savannah, probably prior to about 5-6

> million years ago. It's all based on standard evolutionary theory -

> survival advantage etc.

>

> 1. The aquatic ape theory. Wading in swamps and river shallows to

> catch/collect food obviously favored upright walking.

> 2. Standing on two legs provided an advantage in looking out for

> predators and enemies - long grass etc.

> 3. Standing/walking upright allowed browsing on low-hanging fruit

> without climbing.

>

> Just a few ideas I've collected over the years.

>

> As to whether early hominids/humans were sprinters or long distance

> runners. . . I'd say both -- with endurance the bread and butter

> activity and fast intervals a predator and tribal conflict survival

> tool.

***

Members may be interested in the following:

Taken from (www.bases.org.uk):

Molecular Exercise Physiology

Endurance training - Presentation 2

Henning Wackerhage

Bramble DM and Lieberman DE. Endurance running and the evolution of

Homo. Nature 432, 345-352, 2004. In this landmark paper, Bramble and

Lieberman argue that the anatomy of human beings has been selected

for endurance running. The compare human beings and argue that human

beings are actually very good at covering long distances when

compared to numerous other species. Many skeletal features are

advantageous for endurance running especially when compared to close

species. They hypothesize that endurance running helped hominids to

exploit protein-rich resources such as meat, marrow and brain.

If the evolutionary pressure was favouring an endurance running human

then our anatomy, biochemistry and muscle function may have all been

selected for endurance running.

================

How Running Made Us Human

http://www.biology.utah.edu/bionews2.php?story=bramble111704.txt

November 17, 2004 - Humans evolved from ape-like ancestors because

they needed to run long distances - perhaps to hunt animals or

scavenge carcasses on Africa's vast savannah - and the ability to run

shaped our anatomy, making us look like we do today.

That is the conclusion of a study published in the Nov. 18 issue of

the journal Nature by University of Utah biologist Dennis Bramble and

Harvard University anthropologist Lieberman. The study is

featured on Nature's cover.

Bramble and Lieberman argue that our genus, Homo, evolved from more

ape-like human ancestors, Australopithecus, 2 million or more years

ago because natural selection favored the survival of

australopithecines that could run and, over time, favored the

perpetuation of human anatomical features that made long-distance

running possible.

" We are very confident that strong selection for running - which came

at the expense of the historical ability to live in trees - was

instrumental in the origin of the modern human body form, " says

Bramble, a professor of biology. " Running has substantially shaped

human evolution. Running made us human - at least in an anatomical

sense. We think running is one of the most transforming events in

human history. We are arguing the emergence of humans is tied to the

evolution of running. "

That conclusion is contrary to the conventional theory that running

simply was a byproduct of the human ability to walk. Bipedalism - the

ability to walk upright on two legs - evolved in the ape-like

Australopithecus at least 4.5 million years ago while they also

retained the ability to travel through the trees. Yet Homo with

its " radically transformed body " did not evolve for another 3 million

or more years - Homo habilis, Homo erectus and, finally, our species,

Homo sapiens - so the ability to walk cannot explain anatomy of the

modern human body, Bramble says.

" There were 2.5 million to 3 million years of bipedal walking [by

australopithecines] without ever looking like a human, so is walking

going to be what suddenly transforms the hominid body? " he

asks. " We're saying, no, walking won't do that, but running will. "

Walking cannot explain most of the changes in body form that

distinguish Homo from Australopithecus, which - when compared with

Homo - had short legs, long forearms, high permanently " shrugged "

shoulders, ankles that were not visibly apparent and more muscles

connecting the shoulders to the head and neck, Bramble says. If

natural selection had not favored running, " we would still look a lot

like apes, " he adds.

I Run, Therefore I Am

Bramble and Lieberman examined 26 traits of the human body - many

also seen in fossils of Homo erectus and some in Homo habilis - that

enhanced the ability to run. Only some of them were needed for

walking. Traits that aided running include leg and foot tendons and

ligaments that act like springs, foot and toe structure that allows

efficient use of the feet to push off, shoulders that rotate

independently of the head and neck to allow better balance, and

skeletal and muscle features that make the human body stronger, more

stable and able to run more efficiently without overheating.

" We explain the simultaneous emergence of a whole bunch of anatomical

features, literally from head to toe, " Bramble says. " We have a

hypothesis that gives a functional explanation for how these features

are linked to the unique mechanical demands of running, how they work

together and why they emerged at the same time. "

Humans are poor sprinters compared with other running animals, which

is partly why many scientists have dismissed running as a factor in

human evolution. Human endurance running ability has been

inadequately appreciated because of a failure to recognize that " high

speed is not always important, " Bramble says. " What is important is

combining reasonable speed with exceptional endurance. "

Another reason is that " scientists are in developed societies that

are highly dependent on technology and artificial means of

transport, " he adds. " But if those scientists had been embedded in a

hunter-gatherer society, they'd have a different view of human

locomotor abilities, including running. "

Why Did Humans Start Running?

The researchers do not know why natural selection favored human

ancestors who could run long distances. For one possibility, they

cite previous research by University of Utah biologist r,

who hypothesized that endurance running evolved in human ancestors so

they could pursue predators long before the development of bows,

arrows, nets and spear-throwers reduced the need to run long

distances.

Another possibility is that early humans and their immediate

ancestors ran to scavenge carcasses of dead animals - maybe so they

could beat hyenas or other scavengers to dinner, or maybe to " get to

the leftovers soon enough, " Bramble says.

Scavenging " is a more reliable source of food " than hunting, he

adds. " If you are out in the African savannah and see a column of

vultures on the horizon, the chance of there being a fresh carcass

underneath the vultures is about 100 percent. If you are going to

hunt down something in the heat, that's a lot more work and the

payoffs are less reliable " because the animal you are hunting often

is " faster than you are. "

Anatomical Features that Help Humans Run

Here are anatomical characteristics that are unique to humans and

that play a role in helping people run, according to the study:

-- Skull features that help prevent overheating during running. As

sweat evaporates from the scalp, forehead and face, the evaporation

cools blood draining from the head. Veins carrying that cooled blood

pass near the carotid arteries, thus helping cool blood flowing

through the carotids to the brain.

-- A more balanced head with a flatter face, smaller teeth and short

snout, compared with australopithecines. That " shifts the center of

mass back so it's easier to balance your head when you are bobbing up

and down running, " Bramble says.

-- A ligament that runs from the back of the skull and neck down to

the thoracic vertebrae, and acts as a shock absorber and helps the

arms and shoulders counterbalance the head during running.

-- Unlike apes and australopithecines, the shoulders in early humans

were " decoupled " from the head and neck, allowing the body to rotate

while the head aims forward during running.

-- The tall human body - with a narrow trunk, waist and pelvis -

creates more skin surface for our size, permitting greater cooling

during running. It also lets the upper and lower body move

independently, " which allows you to use your upper body to counteract

the twisting forces from your swinging legs, " Bramble says.

-- Shorter forearms in humans make it easier for the upper body to

counterbalance the lower body during running. They also reduce the

amount of muscle power needed to keep the arms flexed when running.

-- Human vertebrae and disks are larger in diameter relative to body

mass than are those in apes or australopithecines. " This is related

to shock absorption, " says Bramble. " It allows the back to take

bigger loads when human runners hit the ground. "

-- The connection between the pelvis and spine is stronger and larger

relative to body size in humans than in their ancestors, providing

more stability and shock absorption during running.

-- Human buttocks " are huge, " says Bramble. " Have you ever looked at

an ape? They have no buns. " He says human buttocks " are muscles

critical for stabilization in running " because they connect the

femur - the large bone in each upper leg - to the trunk. Because

people lean forward at the hip during running, the buttocks " keep you

from pitching over on your nose each time a foot hits the ground. "

-- Long legs, which chimps and australopithecines lack, let humans to

take huge strides when running, Bramble says. So do ligaments and

tendons - including the long Achilles tendon - which act like springs

that store and release mechanical energy during running. The tendons

and ligaments also mean human lower legs that are less muscular and

lighter, requiring less energy to move them during running.

-- Larger surface areas in the hip, knee and ankle joints, for

improved shock absorption during running by spreading out the forces.

-- The arrangement of bones in the human foot creates a stable or

stiff arch that makes the whole foot more rigid, so the human runner

can push off the ground more efficiently and utilize ligaments on the

bottom of the feet as springs.

-- Humans also evolved with an enlarged heel bone for better shock

absorption, as well as shorter toes and a big toe that is fully drawn

in toward the other toes for better pushing off during running.

The study by Bramble and Lieberman concludes: " Today, endurance

running is primarily a form of exercise and recreation, but its roots

may be as ancient as the origin of the human genus, and its demands a

major contributing factor to the human body form. "

-------------

Carruthers

Wakefield, UK

July 25, 2007

Wow. What a complete irony that the largest buttocks are those parked on sofas

consuming mass quantities of cheesy puffs....who have low expectations of even

slow self locomotion and happily park these prominent buttocks on mobile

scooters now rather than even try to move themselves in stores?

Perhaps nature's intent has been lost on the human race?

I don't run though, Ken. Caution learned by watching fellow PL get sidelined by

needless running lol.

the other reason for prominent buttocks (other than mating displays?) would be

buttock intensive operations such as the squat and deadlift...?

With tongue firmly in the FACIAL cheek here,

The Phantom

aka Schaefer, CMT, CSCS, competing powerlifter

Denver, Colorado, USA

-------------- Original message --------------

From: CoachJ1@...

In a message dated 7/25/2007 8:20:10 AM Central Daylight Time,

Carruthersjam@... writes:

Human buttocks " are huge, " says Bramble. " Have you ever looked at

an ape? They have no buns. "

****

We used this research as an epigram for our Lisle Lions " Mane Event " cross

country invitational t-shirts two years ago:

â€œRunning seems to be the only reason that we have prominent buttocks.â€

-- Dr. Lieberman, Harvard University

==============================

July 25, 2007

Well, yeah. Or, I should be a really, really good runner.