BIPEDALISM: ARE WE HUMANS MEANT TO WALK?

A study of our evolutionary journey to bipedalism and the

consequences

Research Project Author: Beni Trainor

Tutor: Núria Batlle Class: 2n.1

Institut Montserrat de Barcelona

Abstract

Back pain is one of the principal ailments in our modern urban societies, which has

huge economic costs. The aim of this project is to consider the possible relationship

between back pain issues and the way we move. The project analyses, in a very basic

way, the evolution of movement and then focuses on bipedalism, which is the form of

locomotion of the human race. As a result of the study of fossils, hypothesis and a

professional opinion of paleoanthropology this project concludes where, why and how

our ancestors adopted bipedalism as their principal form of locomotion. Bipedalism

offered a great advantage for many reasons; however, there are also negative

consequences for walking as we do. With this said, the project analyses the various

anatomical changes that the body needed to adopt in order to support this form of

movement and, with the help of two professionals from the healthcare world, the work

concludes that back problems are strictly related to lifestyle and longevity. Humans

aren’t supposed to walk upright, or at least, not at the moment. Nevertheless, bipedalism

has provided humans with great evolutionary advantages, which have made us the way

we are today.

Resum

El mal d’esquena és un dels principals problemes de salut a la nostra societat actual que

provoca grans gastos econòmics. En aquest treball em proposo demostrar la possible

relació que existeix entre els mals d’esquena i la nostra manera de caminar. El treball

analitza, de forma bàsica, la evolució del moviment i seguidament es centra en el

bipedisme que és la principal forma de locomoció de l’ésser humà. El treball tracte de

demostrar quan, com i per què es va adoptar la posició bípeda amb l’ajuda d’estudis

fòssils, algunes hipòtesis i la opinió d’un expert en paleoantropologia. El pas al

bipedisme, tot i que ofería molts avantatges, també comportava algunes conseqüències

negatives. El treball analitza, tantmateix, els diferents cambis anatòmics que el cos va

haver d’incorporar per desenvolupar aquesta forma de locomoció. Aquesta part del

treball està recolzada en l’ajuda de dos professionals que treballen en el món de la salut.

La conclusió d’aquest treball és que els problemes d’esquena estan directament

relacionats a l’estil de vida y a la longevitat. L’ésser humà no està disenyat per a

caminar en posició erecta, almenys, no fins al moment. No obstant, no hi ha cap dubte

de que el bipedisme ha proporcionat als humans grans avantatges evolutius sense els

quals no seriem com som a l’actualitat.

Resumen

El dolor de espalda es uno de los principales problemas de salud de la sociedad actual,

que acarrea un gran gasto económico. En este proyecto, me propongo demostrar la

posible relación que existe entre los problemas de espalda y nuestra manera de caminar.

El proyecto analiza, de forma básica, la evolución del movimiento y luego se centra en

el bipedismo que es la principal forma de locomoción del ser humano. El trabajo trata

de demostrar cuándo, cómo y por qué se adoptó la posición bípeda con la ayuda de

estudios fósiles, algunas hipótesis y la opinión de un experto en paleoantropología. El

paso al bipedismo, aunque ofrecía muchas ventajas, también conllevaba algunas

consecuencias negativas. El proyecto analiza, así mismo, los diferentes cambios

anatómicos que el cuerpo tuvo que incorporar para desarrollar esta nueva forma de

locomoción. Esta fase del trabajo se apoya en la ayuda de dos profesionales que

trabajan en el campo de la salud. La conclusión de este trabajo es que los problemas de

espalda están directamente asociados al estilo de vida y a la longevidad. El ser humano

no está diseñado para andar en posición erecta, al menos, no hasta el momento. No

obstante, no cabe duda de que el bipedismo ha proporcionado a los humanos grandes

ventajas evolutivas sin los cuales no seríamos como somos en la actualidad.

Acknowledgments

In this section I wish to express my sincere gratitude to the people who have helped and

supported me while I was working on the project.

I want to give a special thanks to my parents who have helped me day and night since I

started the project until it was finished. I really appreciate all their comments, input and

support.

I also want to thanks to my tutor Núria Batlle for all her patience and support that she

has given me during the entire project and her help in correcting the work.

I want to offer my sincere gratitude and appreciation to Ester Sánchez González, to my

uncle Dr. Erich Koller and Alfonso Par for all their time and effort in answering my

questions and resolving my doubts.

Finally I want thank all the other people that have supported me and helped me to

complete this project and whom I haven’t mentioned specifically.

Table of contents

Introduction……………………………………………………………………………1

1. What is animal locomotion?………………………………………………………..2

2. What is terrestrial locomotion?……………………………………………………3

2.1. Limbless locomotion………………………….………….……………….4

2.2. Rolling locomotion……………………………….……………………….4

2.3. Legged locomotion……………………………….……………………….4

2.3.1. Types of posture…………………….…….………….…………5

2.3.2. Number of legs involved in locomotion…………….………….6

2.3.3. The function and structure of the leg and foot……….……….7

2.3.4. The order in which the limbs move……….….…….……….…8

3. Bipedalism………………………………………………………………..………..10

3.1. The Laetoli Footprints……………………………………………….…10

3.2. Lucy, the Australopithecus afarensis………………….…...……….….11

3.3. Ardi, the Ardipithecus ramidus……………………….……….……….12

3.4. Bone fragments from the Orrorin tugenensis…………………………13

4. Hypotheses……………………………………………………………………..…14

4.1. The Postural Feeding Hypothesis……………………………….....…16

4.2. The Squat Feeding Hypothesis……………………………………….16

4.3. The Savannah Hypothesis…………………………………………….17

4.4. The Energetic Efficiency Hypothesis…………………………………17

4.5. The Meat-eating Hypothesis………………………………………….18

4.6. The Carrying Hypothesis…………………….………………………18

4.7. The Heat Hypothesis………………………………………………….19

4.8. The Threat Display Hypothesis……………………………………..20

4.9. The Aquatic Ape Hypothesis……………………………………..21

4.10. Professional opinion…………………………………………..…22

5. Anatomical changes due to Bipedalism……………………………………24

5.1. The skull…………………………………………………………...25

5.2. The spinal column………………………………………………...25

5.3. The arms…………………………………………………………..27

5.4. The pelvis………………………………………………………….27

5.5. The Legs…………………………………………………………...29

5.5.1. The hip joint………………………………………..…...29

5.5.2. The femur……………………………………………….30

5.5.3. The knee joint…………………………………………..31

5.6. The feet……………………………………………………………32

5.7. Muscular changes………………………………………………..33

6. The consequences of upright posture…………………….……………....34

6.1. Facts and Statistics………………………….…………………..34

6.2. Healthcare professional’s opinions…………………………….36

6.2.1. Postural re-education specialist……………………...37

6.2.2. Orthopaedic doctor…………………………………..39

7. Conclusions……………………………………………………………….41

8. Annexes…………………………………………………………………...43

8.1. Annex 1…………………………………………………………43

8.2. Annex 2……………………………………………………….…47

9. Bibliography………………………………………………………………50

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Introduction

Have you ever wondered why we have so many back problems? Has it ever occurred to

you that they may be related to evolution? I was watching a documentary recently

when, at some point in the program, someone said: “Back problems are caused because

we aren’t really supposed to walk upright”. That statement kept me thinking for a while,

as it had never really occurred to me before.

With this in mind I considered that this would be an interesting topic for my research

project. The objective of this work is to establish a relationship between back pain

ailments and the way we walk. However, the purpose of this project is not to find a

solution but to identify the problem and offer some practical recommendations.

I began by studying the basic mechanisms of how animals started to move and little by

little I have come to understand how our ancestors managed to stand up and walk on

two legs. The truth is there are no definitive answers as to where, when and why this

happened. However, Palaeoanthropologists agree that bipedalism started in Africa 5 to

6, or even 7 million years ago and that it was almost certainly as a consequence of

climatic change. There are several hypotheses trying to solve this puzzle, but to date

nothing is conclusive. Scientific researchers have all come to the same conclusion

which is that walking on two legs is known to have developed much earlier among our

ancestors than our other important attributes which make us the humans we are today.

When our ancestors adopted bipedalism as the principal form of locomotion a set of

skeletal and muscular changes needed to adapt the body to support this new form of

movement. I have studied what theses changes were and how they affected the body.

Finally I compared current facts and statistics related to back pain issues. In considering

the United States, Europe and Catalunya the figures are astounding. Experts in the field

have concluded that back pain, especially lumbar pain, will effect half the adult

population, cause major suffering and will result in huge economic costs to society.

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1. What is animal locomotion?

Animal locomotion is the way living organisms self-propel themselves for survival. It is

the vital factor that makes the difference between living and dying. It is crucial to be

able to move for other reasons, such as finding food, a suitable habitat and to escape

from predators.

Energy efficiency is a very important factor that has to be considered in the movement

of a living organism. For example migratory animals that need to travel vast distances

using repetitive movement need a more efficient body structure to save energy. Other

animals that don’t migrate also need energy to produce bursts of speed and power.

Therefore efficiency is one of the most important factors that determines an animal’s

muscular and skeletal structure. Throughout centuries animals have evolved and

perfected their bodies to make them more efficient and we human beings are no

exception.

Animals have adapted themselves to move in almost all environments, from water and

air to underground caves. Since energy is the vital source for life it is important not to

waste it. Moving in an environment can present contradictions. If the environment in

which an animal is moving is fluid, air or water, energy will be used in maintaining its

balance. In terrestrial environments gravity presents a difficulty that may have to be

overcome.

Eadweard Muybridge

Animal Locomotion, Plate 700, 1887

Collotype

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2. What is terrestrial locomotion? What types are there?

Terrestrial locomotion is the ability to move in a terrestrial environment, in other words,

movement on land. Scientific studies have proved that life began in the sea. The ability

to move in water made the effect of gravity irrelevant, but other problems arose from

the fact that swimming in water creates friction and therefore wastes energy.

When living creatures began to move from the sea to the land the friction produced by

water disappeared but the effect of gravity became more important. This originated in

the need to develop a propulsive mechanism for movement on land.

For this mechanism to be efficient and effective there are a few common requirements

that need to be present. The body of an animal would have to be sized and shaped

properly in order to provide for proper weight distribution throughout. These limbs

make up the supporting structure, which provides stability for the animal, and also

needs to be strong enough to exert sufficient force to make the animal move in reaction.

It is also important that animals can control the magnitude and direction of these

locomotive forces in order to accelerate, turn and stop without sacrificing excessive

stability. There are three main forms of locomotion common to terrestrial animals:

Legged, Limbless and Rolling.

This project will focus entirely on legged locomotion. I will present briefly what the

limbless and rolling forms of locomotion are and why they are important. Then, I will

concentrate on legged locomotion and bipedalism in particular.

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2.1. Limbless locomotion

There are many terrestrial limbless vertebrate and invertebrate animals. These animals

may seem immobile due to their lack of legs, but they can achieve movement with the

underside of their bodies. All limbless animals have evolved from cold-blooded

relatives.

In the case of these animals the limbs are replaced by the underside of the body, in some

cases it can be dry and smooth like a snake or in others the body itself creates mucus

that helps move the animal. Other limbless species, such as worms and leeches, employ

different techniques to transport themselves through the environment they live in. For

example, leeches that anchor themselves with suction cups to move and snakes that

move the body sideways.

2.2. Rolling locomotion

A small number of animals use rolling as a means of movement

and sometimes use other forms as well.

Rolling animals can be divided into those that roll under the

force of gravity or wind and those that roll using their own power.

The animals that roll by the force of gravity normally use their own

bodies to form a ball, which they then roll when under threat. Other rolling animals not

only use this method for escaping from danger but also as a means of propulsion.

2.3. Legged locomotion

Moving with the help of limbs is the most common form of terrestrial locomotion. It is

the basic locomotion system for vertebrate animals and arthropods (insects). Not all

legged animals are the same. There are some differences. Important factors, which

differentiate animals with limbs, are their posture or way their body is supported by

their limbs, the number of limbs, and the functional structure of their legs and feet.

There are also differences in how animals move their legs when they are in motion, such

as walking, running or jumping. These forms of movement are called gaits and they are

energy efficient.

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2.3.1. Types of posture

Terrestrial animals also need a solid structure to be able to support their body weight. In

order to achieve movement it is important that their limbs are well fitted to the body.

There are three ways these animals support their bodies, they are known as postures: the

sprawling posture, the semi erect posture and the fully erect posture.

Occasionally, depending on the circumstances, animals may use different postures to

give them an advantage. Take for example the situation where rabbits stop hopping

around and stand up, this allows them to increase their visual field.

It is important and interesting to know that, so far, no detectable waste of energy has

been discovered when there is a transition from one posture to another.

A) The sprawling posture

This posture is the first limb posture to have evolved and it

is from this one that the other erect postures originated. In

this posture normally the lower limb is held vertical and the

upper limb horizontal. If the animal is too large the upper

limbs may increase their angle allowing the body to move

without touching the ground but normally the body is

dragged along the ground. Examples of this case are

salamanders and lizards.

B) The semi-erect posture

This posture is interpreted as an extremely elevated

sprawling posture. Since sprawling was the first posture

to appear, the semi-erect posture very likely evolved from

it. Large lizards and giant turtles use this form of posture

to move.

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C) The fully erect posture

This last posture is a typical characteristic found in

warm-blooded creatures such as birds and mammals. In

each case, however, the posture developed

independently. In this case the limbs support the body

weight vertically.

This posture is normally related to the fact that these types of animals, that is to say

warm-blooded, produce and maintain their own heat internally through the consumption

of calories (endothermy) and not externally by absorbing heat from the sun’s rays, as is

the case for cold-blooded creatures. This endothermic process results from a number of

metabolic functions. It allows the body to breathe and move simultaneously and,

therefore, extends the duration of activity, whereas in the case of clod-blooded animals

they require “warming up” between bursts of action.

The fully erect posture is understood to be the most recent one to have evolved, but that

does not mean that it is the best developed adapted to its environment. An example that

makes this evident is the evolution of the posture of the crocodile. This animal evolved

from a giant reptile that used the fully erect posture to move, but nowadays crocodiles

move with a sprawling posture. It seems that evolution has gone backwards instead of

forwards, but in fact evolution has adapted the crocodile efficiently to survive. Evidence

of their adaptability is that they are to be found in all the continents in the world (except

Europe).

2.3.2. Number of legs involved in locomotion

The number of legs involved in locomotion varies

greatly among animals. This ranges from animals

that use one leg to move to millipedes that use

hundreds.

Animals that employ unipedal movement are very

rare. One clear example of this is an insect called a

Springtail. Although it has six legs, it uses one special leg when it feels threatened to

jump away and avoid danger, and also, to jump to other leaves close by.

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Animals that move with the help of two legs are called bipedal. Birds are a group that

are exclusively bipedal but there are a number of mammals that also use two legs to

move, most of those hop like kangaroos and jerboas. There are

also a few bipedal mammals that use combined ways of moving,

sometimes they can run others times they walk. Other species of

vertebrate and invertebrate animals are rarely seen walking on

two legs, but there are some exceptions: cockroaches and some

lizards can run on their two hind legs only when escaping from

danger.

With the exception of birds, all terrestrial vertebrate groups with

legs are mostly quadrupedal. Some insects are also quadrupeds but most of them are

hexapods. Having 6 legs or more is very helpful to maintain stability, as they are able to

maintain a triangle of support by using just 3 legs.

Starting with 8 legs, in the case of spiders, the

number increases considerably. The animals

that have the greatest number of legs are,

without doubt, the invertebrates, which range

from 14, in the case of crustaceans to

centipedes and millipedes that have hundreds.

2.3.3. The function and structure of the leg and foot

The legs of tetrapod animals, which walk on four legs, consist of an internal bone

attached to muscle and ligaments

forming the essential joints of the body.

These are: the hip and shoulder joints,

the knee and elbow joints, and the ankle

joints, where the foot is attached to the

leg.

In adapting to different environments the

limbs of animals vary greatly in size and

form. However, limbs of terrestrial

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animals normally consist of the same bones and muscles. Even some primitive aquatic

animals share a similar limb structure to our own.

The basic form of the vertebrate foot has five toes, however some animals have

developed more or less than this standard. Feet have evolved in many different ways

depending primarily on the animal's needs. Important differences of foot structure result

from weight placement. Most vertebrates, such as amphibians, reptiles, and some

mammals walk on the underside of the foot; other mammals distribute their weight to

the toes, which allows them to move with a bigger stride and more speed. In some other

cases, animals such as horses walk on the tips of their toes. This further increases their

stride length and, therefore, their speed. A few mammals are also known to walk on

their knuckles; apes are an example of this.

The form of limbs among terrestrial invertebrates varies greatly. Arthropod legs are

jointed and supported by hard external armour, with muscle attached to the internal

surface. The other group of terrestrial invertebrates, velvet worms, have soft stumpy

legs supported by a hydrostatic skeleton, which is a structure consisting of a muscle

cavity filled with fluid.

2.3.4. The order in which the limbs move

Animals have a great number of ways of moving, which are used for different purposes

such as running away from predators. Those, which have four legs, employ three

different forms of motion: walking, running and leaping. Walking is the principal form

of motion, and is common to almost all legged animals. An animal is considered to be

running when, at some point, it reaches a “moment of suspension”, when no feet are

touching the ground. These moments of suspension are not only reached when running

but also when leaping.

There are many different kinds of gaits. Animals will use one or another to suit their

own purpose such as reaching a certain speed because of the terrain.

Humans have two important gaits, which they use to move: walking and running. But

under rare circumstances they may crawl to fit through tight spaces.

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When walking or running animals normally alternate the legs of the two sides of the

body. In other cases animals alternate their front and back legs to move. Another gait,

which is different to the previous ones, is hopping, where the hind legs are together

when jumping.

Most animals position their heads in the

direction in which they are moving.

However there are exceptions. Crabs, for

example, can move sideways. Other animals

can move forwards and backwards with

equal facility and some only backwards. Examples of these are rats, when moving

through tight tunnels, and crayfish that move better and faster going backwards than

forwards.

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3. Bipedalism

Bipedalism means walking with two limbs or legs. Humans nowadays move using a

bipedal stride but this has not always been the case. As a result of the discovery of

fossils in Africa, Palaeoanthropologists (experts in the study of anthropology related to

primitive man) have concluded that our ancestors walked on two legs.

Bipedalism has a number of adaptive advantages, such as energy efficiency. This form

of movement was developed independently among different animals. From very

primitive lizards that used their hind legs to run, to dinosaurs, birds, and mammals. We

modern humans are probably one of the last species to develop an upright stance but we

are unique in how we move; no other animal walks on two legs for its entire life as we

do.

For millions of years, the earliest hominids were a lot like other apes. They were short,

had tiny brains compared with modern humans, and could not speak or make tools. But

there was a profound difference that set them apart. They could stand up and walk for

long periods of time. Bipedalism was the first great transformation of our ancestors,

coming long before the evolution of all the other attributes that make us human.

We know all this thanks to the discovery of fossils. From the over 500 discoveries to

date, this project will concentrate on the most important of these, especially those that

are crucial to understanding how our ancient ancestors moved.

3.1. The Laetoli Footprints

At Laetoli in Tanzania (Africa), a set of two individual

Australopithecus afarensis footprint’s walking along

side by side have been dated to 3.6 million years ago.

As a result of the remarkable conditions of the terrain,

the footprints were preserved all this time. Ashes from

a volcano near by and rain created a wet material

similar to cement in which these two individuals left

their unique signature.

The footprints are identified as not fully human due to

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the fact the feet had ape-like features, such as a slightly diverging big toe, but it proves

beyond doubt that millions of years ago our ancestors were already walking on two legs.

By analysing the volcanic ash researchers were able to conclude that the footprints were

around 3.6 million years old. During this time there could be two possible owners: the

Kenyanthropus platyops or the Australopithecus afarensis. It is very probable that the

Australopithecus afarensis were the ones to leave the footprints because of the

discovery of bones of these creatures nearby.

The discovery of the footprints and skeletal structures excavated at Laetoli showed clear

evidence that bipedalism preceded enlarged brains in hominids.

3.2. Lucy, the Australopithecus afarensis

Lucy is the common name of a fossil found in Ethiopia

(Africa) in 1974. It is of great importance because it is one

of the oldest ancestors and early hominids, the

Australopithecus afarensis, dating from over 3 million

years ago.

Although the recovery of the skeleton is not complete it

provides a clear image of what these ancestors were like.

Their dimensions were about the same size as one of

today’s adult chimpanzees and they had similar

musculature and brain sizes.

This evidence clearly reveals the discovery that the

Australopithecus afarensis had tiny brains in comparison to modern humans but they

were able to walk on two legs.

Lucy looked more or less like a chimpanzee. Her skull was

similar to a chimpanzee’s, but her pelvis and leg bones were very

similar to those of modern humans.

What makes this discovery so important is that it reveals that 3

million years ago these ape-like creatures were able to walk on

two legs rather than four. The valgus knee is one of the fossil

remains that reveal that the skeleton was in a process of

transformation: the arms were shortening and the legs were

beginning to grow longer.

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Another detail, which indicated that Lucy walked on two legs, was that of a lumbar

curve, which meant the spinal column was starting to transform from an arch typical in

primitive quadrupedal ancestors to an “s-like” shape similar to that found in modern

humans.

3.3. Ardi, the Ardipithecus ramidus

More skeletal fossilised remains have been found since the discovery

of Lucy. Ardi is the name of the remains of the skeleton of an

Ardipithecus ramidus, an even older hominid than Lucy, aged about

4.4 million years old. The importance of this discovery lies not only

in its age, but also in that the skeleton is in perfect conditions. Most

of the skull, teeth, hands and feet are still intact.

Again Ardi, a 4.4 million year old hominid, is found to be bipedal.

This time, the feet reveal that she did walk on her hind legs because

they were flatter and better suited for this purpose.

The observation of the pelvic structure of this creature reveals its

saddle-like structure capable of keeping the torso in

balance when walking and of giving birth.

The reconstruction of the pelvis reveals relevant

human-like features. It isn’t as long as that found in

chimpanzees and the ilium (which is the blade

located at the top of the pelvis) is starting to twist

providing support for this new form of bipedal

locomotion.

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3.4. Bone fragments from the Orrorin tugenensis

Even older fossils have been found in Africa. These

fragments found in Tugen (Kenya) are part of the lower

limbs of an Orrorin tugenesis, which lived around 6

million years ago. Only from these few fragments

recovered it was deduced that the legs were tilted

towards the centre of the body’s mass, typical of

hominids.

Several theories indicate that, indeed, this creature

walked on two legs but was also able to climb trees in

search of food and to escape from its predators.

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4. Hypotheses

There are several theories or hypotheses as to how and why humans developed

bipedalism as a means of movement. At this stage there is nothing conclusive, because

there is not sufficient reliable proof to confirm one theory or another so it is a still a

controversial issue open to debate. The discovery of hominid fossils has been the key

factor in supporting these different theories. These discoveries all point to the same

conclusion: in human beings bipedalism was present well before any of the other

important human features, such as brain enlargement.

The most common hypothesis suggests that some 7 million years ago our ancestors or

hominids began to adapt to a much warmer climate. Drier savannas and woodlands were

replacing the huge forests of Africa. These apes needed to survive, so they stopped

climbing trees and began to walk long distances out in to the savannah to find food to

survive.

This project will analyse the most important and current theories proposed and will try

to make a case for the most convincing and plausible one supported by a professional of

the subject matter.

An important differentiation has to be made clear; bipedalism like many other forms of

locomotion first needed to be introduced as a posture. The first two hypotheses expose

different arguments as to how and why this happened. The following hypotheses are

concerned with the origin of habitual bipedalism; the order in which they are presented

is of no specific importance.

On the following page there is a diagram presenting the basic characteristics of these

hypotheses.

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3. The Savannah Hypothesis

HYPOTHESIS OF THE ORIGIN

OF HABITUAL BIPEDALISM

PRINCIPAL OBJECTIVES

To free the hands allowing for the manufacture of tools and the

transportation of meat

4. The Energy Efficiency

Hypothesis

To develop an efficient form of locomotion for travelling long

distances

5. The Meat-eating

Hypothesis

To free the hands allowing for

the transportation of meat

6. The Carrying or Male

provisioning Hypothesis

To free the hands allowing male partners to provide and transport food for the family and to allow female partners a better way of carrying food

7. The Thermoregulatory or

Heat Hypothesis

By standing up and walking, hominids would avoid excessive heat on their bodies and improve

ventilation

8. The Threat Display

Hypothesis

To scare off predators by

appearing to be larger

9. The Aquatic Ape

Hypothesis

To develop an efficient form of movement in an aquatic

environment

1. The Postural Feeding

Hypothesis

HYPOTHESIS OF THE ORIGIN OF THE ERECT POSTURE

2. The Squat Feeding

Hypothesis

OBJECTIVE

To obtain food high up in the trees

To obtain food from the ground

METHOD

Standing up and placing the whole body weight on the hind limbs

Squatting down and gradually placing the body weight over the hind limbs

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4.1. The Postural Feeding Hypothesis

Author /s: Dr. Kevin D. Hunt (1994).

Theory: This theory suggests that bipedalism developed as a feeding posture first and

then evolved into a form of locomotion. As a result of the study of early hominids and

chimpanzees, which are close relatives to modern humans, Hunt argues that our

ancestors started to stand on their hind legs in order to reach food that was higher up in

trees and bushes. These bipedal stances presented an efficient and effective way of

obtaining food and, within time, they were applied to other activities eventually

evolving into a form of locomotion.

Lucy the Australopithecus afarensis appears to have attributes that clearly reveal that

she could walk upright but not as efficiently as today’s modern humans. Her upper

limbs however indicate that she was indeed used to hanging from trees as Hunt

proposes.

4.2. The Squat Feeding Hypothesis

Author/ s: Jonathan Kingdon (1997).

Theory: His hypothesis suggests that bipedalism was not fully developed over a short

period of time but gradually introduced by squatting down to feed in forests rich in food

found on the floor. This new posture began to adapt the body for walking upright in the

future. The pelvis and legs were going to support more weight so they needed to be

adjusted for balanced standing. In this evolutionary change the arms were beginning to

lose their capacity to support weight and hang from trees. This theory suggests that

quadrupedal locomotion gradually became less efficient and was discarded through

natural selection.

At this point, we can certainly conclude that the erect posture evolved from either one of

the previous hypotheses. From this point on, the analysis of the other possible

explanations for the origin of habitual bipedal movement will be dealt with.

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4.3. The Savanna Hypothesis

Author/ s: proposed by Charles Robert Darwin (1871) and then adopted by Elizabeth

Vrba.

Theory: This hypothesis suggests that a few million years ago hominids moved out of

the jungle on to the large savannas. This adaptation produced the need to develop an

efficient form of terrestrial movement, which also would allow for hominids to carry

food and, further on, to handle

weapons for hunting. As the savanna

became the habitat of these early

hominids longer legs were needed to

assist better movement.

Elizabeth Vrba’s theory suggests that

this change that transformed the

African ecosystem from jungles to savannas was due to a period global warming. With

the study and observation of African antelopes she explains that ecosystems periodically

experienced significant losses, which then resulted in massive extinctions. She claims

that this could have happened with the African ecosystem, which, as a result, led to the

destruction of trees, leading hominids to acquire upright efficient walking.

Contradictions: The finding of fossilized primitive tools does not appear to provide

sufficient evidence to support Darwin’s Savanna Hypothesis because early hominids are

considered to have walked much earlier than the age of these tools would suggest.

4.4. The Energetic Efficiency Hypothesis

Author/ s: Peter Rodman and Henry McHenry (1980).

Theory: This hypothesis asserts an alternative explanation to the Savannah Hypothesis.

The climatic change, which forced hominids to move from dense forests to large

savannas, also created the need to move for finding food and survival. In this case the

hypothesis suggests that quadrupedalism was not efficient enough for travel and within

time it was replaced by bipedalism, which offered greater efficiency over longer

distances.

It sounds very convincing that one of the principal reasons for adopting bipedalism was

to save energy. As seen in the evolution of locomotion, energy efficiency is the vital

factor to support life.

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When hominids abandoned quadrupedalism they sacrificed stability, easier child

bearing and most important of all speed. So, in conclusion, there had to be a good

reason for adopting bipedalism over quadrupedalism and energy efficiency is a very

plausible explanation.

Contradictions: This hypothesis has some contradictions because indeed for modern

humans walking long distances on two feet is much more efficient than using four

limbs. But this form of walking was not developed at this stage among early hominids.

The human fossil record provides sufficient knowledge to prove it. Bipedalism was

present but it was still not as efficient as in today’s human beings.

4.5. The Meat-eating Hypothesis

Author/ s: Craig Stanford (2003).

Theory: This hypothesis is very similar to the popular Savannah Hypothesis and the

Energetic Efficiency Hypothesis. The difference that distinguishes this theory from the

others is its emphasis on eating meat. Stanford also proposes that there was a climatic

change in Africa 5 to 6 million years ago that transformed the environment from large

dense forests to broad dry savannas. Hominids were forced to travel long distances to

find sources of food.

Craig Stanford presents this model as a result of the study of chimpanzees and gorillas.

His main concern focuses on feeding situations, specifically when eating meat. He

suggests that early hominids needed to develop an efficient form of locomotion to find

and transport meat. This diet was probably one of the factors that led to the

development of brain enlargement.

4.6. The Carrying or Male Provisioning Hypothesis

Author/ s: Claude Owen Lovejoy (1981).

Theory: Lovejoy saw in bipedalism a great advantage in the ability for hominids to

carry food. As the East Africa climate was drying out some 7 million years ago, food

sources were becoming scarce and were to be found further and further apart. At that

time, hominids would have had to walk long distances to gather food for survival and

for feeding their offspring. This became a problem for females trying to raise their

young so the solution, according to Lovejoy, was that every male partner would care for

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their own female partner and the newborn, which in technical terms is called

monogamy. Bipedalism arose as a handy form of moving, leaving the hands free to

gather and deliver food to the family. The male partners travelled very long distances,

the female and offspring were left behind but they also needed to develop their own

form of movement to find and carry food locally. So probably bipedalism also

developed among females, according to Lovejoy’s hypothesis.

Lovejoy supports his theory using the argument of the differences between male and

female canine teeth and body size to prove that the Australopithecus afarensis were

monogamous.

In summary, Lovejoy argues that walking upright probably was developed for a number

of reasons. The factor that could have determined this change was most likely to do

with an alteration in the environment, which resulted in a change in food supplies.

When this change took place, bipedalism offered an advantage for those hominids to

survive.

Contradictions: Other evidence found in the two genders suggests a polygamous

mating system typical of chimpanzees prevailed at the time.

4.7. The Heat or Thermoregulatory Hypothesis

Author/ s: Dr. Peter Wheeler (1984).

Theory: He proposed a model in which bipedalism was developed in hominids because

of the heat of the savannah, which may have caused skin damage and dehydration.

Wheeler explained that by standing up cooler air could flow better allowing hominids to

feel more comfortable and to

eventually develop an efficient

evaporative cooling system, which

was simply sweating. This theory

also suggests that by standing up

less body surface was exposed to

the sun’s radiation, which was

intense near the equator, resulting in a reduction in heat absorbed. In the case of our

quadrupedal ancestors the whole back, head and even legs would have been exposed to

the sun, making it very hard for them to survive in high temperatures. Furthermore the

20

improvement of the thermoregulatory system for surviving in harsh conditions could

probably be the principal cause for fur loss.

4.8. The Threat Display Hypothesis

Author/ s: Joseph Jordania (2011).

Theory: This theory does not have much relation to other hypothesis presented.

Jordania suggests that bipedalism was developed as a form of defence strategy. Having

an upright position gave hominids an exaggerated appearance, which was used to scare

off predators and competitors. Jordania also thought that while standing up hominids

would try make loud sound signals to add to their threat defence strategy.

Jordania’s hypothesis interprets changes in body structure as a development to achieve a

better defence strategy. Longer and more adapted legs gave hominids the possibility to

stand up for a longer periods of time. Other morphological changes were acquired to

exaggerate their appearances even more. Furthermore rhythmic and synchronous sounds

were incorporated to their performances. Another important feature, which is also

present today in humans, was the development of body odour that could have been used

as a signal to ward off potential predators.

In summary, it seems odd but acceptable that our ancestors developed bipedalism

simply for warding off potential predators. When observing chimpanzees, our closest

relative, we can appreciate their form of lifestyle, which was probably similar to the one

of our ancestors. These creatures all live in large families as we do; they also eat,

reproduce themselves and even fight. When it was essential for these early hominids to

survive their main worries would probably have been to protect themselves and their

offspring. To achieve security for the family a well-planned defence strategy needed to

be developed. The idea of bipedalism being a defence strategy sounds hard to believe

but is understandable. Hard evidence substantiating this theory is scarce.

Contradictions: There are some contradictions to this hypothesis. Many animals use

warning signals when they feel threatened. Early hominids may have used these defence

strategies to alert of potential predators but there is little evidence to support this

argument.

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4.9. The Aquatic Ape Hypothesis

Author/ s: proposed by Alastair Hardy (1960) and championed by Elaine Morgan

(1982).

Theory: They both argued that there was a moment in human history when our

ancestors lived in an aquatic environment but then returned to land. During the time

they were in contact with the water, bipedalism and other typical modern attributes may

have developed. There is no solid evidence to support this theory but there are human

characteristics that Elaine Morgan suggests to have evolved during the possible

adaptation to water: high levels of subcutaneous fat probably were formed to help when

floating; the adaptation to breath during longer periods of time would have helped when

diving deep; and even the lack of hair would have assisted when swimming in water by

reducing drag.

This hypothesis provides a very doubtful explanation as to why we developed bipedal

movement and became efficient at it. The study and observation of evolution shows that

drastic developments can be developed as a response to changes in the environment.

Examples of this are terrestrial animals that began having aquatic lifestyles and

gradually developed limbs to move on land. If indeed human ancestors once lived close

to water and there developed bipedalism not as a form of land locomotion but as a form

of propulsion in water, why are we the only ones among primates to have lived there?

Why didn’t we stay in the jungle with the chimpanzees and gorillas? Given the

possibility that there was flooding, which obliged early hominids to develop certain

features to allow life on water, why only us and not all the terrestrial animals moved

into water? If flooding was not the cause that moved our ancestors to water, what was

the cause? It seems confusing the return to water after million of years of adaptation to

land for no reason.

In conclusion this hypothesis does not seem very feasible. It gives a reasonable

explanation for some of the human features that distinguishes us, but there is no solid

evidence to support that it was the only cause.

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4.10. Professional opinion: An interview with Alfonso Par, expert in

paleoanthropology

Alfonso has spent many years producing documentaries in the field of

palaeoanthropology. I discussed with him over a period of a few hours the hypotheses

regarding the development of bipedalism currently open to debate.

Initially he told me that bipedalism is neither a unique or new form of locomotion.

Many primates and small rodents are able to walk for short periods of time using their

hind limbs; this was also the case in hominids. When they started to develop an upright

stance it is very probable that is was not for the purpose of habitual movement. This is

supported by the fact that chimpanzees can move over short periods of time on two legs

and still move quadrupedally. So now we know that bipedalism was probably used for

other reasons before it became the principal form of locomotion for these creatures. I

am only concerned with the cause which made hominids adopt habitual bipedalism so I

won’t go into detail about the period before this happened.

Alfonso suggests that bipedalism did not develop as a result of one single cause; on the

contrary, he maintains that there were many causes that propelled these creatures to

adopt this form of locomotion. Therefore there are more than one hypotheses that are

valid and can be proven.

During the glacial ages, even though it seems surprising, seas sank causing droughts in

many of parts of the world. It is well documented that on at least two occasions in the

course of the history of the planet the Mediterranean Sea completely dried out.

Consequently the African ecosystem changed transforming the jungles into large

savannas, which were harsh and hostile. In order to survive, hominids needed to figure

out someway to obtain food, escape from predators and avoid excessive heat. The

solution was to adopt bipedalism as a habitual form of movement offering them a great

evolutionary advantage.

Alfonso suggests that the main cause for the development of bipedalism in hominids

was the need for them to free their hands in order to fabricate and manipulate tools used

to hunt and to transport food. The evidence that supports his opinion is the fact that

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chimpanzees on occasions fabricate tools in order to obtain food and that fossilized

tools were dated much later than bipedalism doesn’t necessarily mean hominids didn’t

fabricate tools. These arguments are to be found separately or together in the hypotheses

explaining the development of bipedalism.

As mentioned before, there were other reasons, found separately or together in several

hypotheses, which made hominids adopt habitual bipedalism. In the savannah the

climate was dry and extremely hot. Bipedalism offered a great advantage over

quadrupedal animals because it reduced the amount of sun radiation affecting the body.

Also, even though this form of locomotion was not well developed yet, the long

distances, which hominids needed to walk in order to obtain food, became easier to

achieve because it was more efficient. Additionally, when hominids stood up their

visual field increased and also their appearance was used to ward off potential predators.

Alfonso told me about another very interesting observation, which is included in one of

the hypothesis. When the dense forests started to dry out resulting in large savannas,

hominids adopted a new diet composed principally of meat because plants were scarce

and normally inedible. This diet was probably and very certainly one of the factors that

promoted brain enlargement because it provided a lot of proteins. Another factor, which

also probably affected brain enlargement, was the exercising of the brain in the tool

making process.

In conclusion, Alfonso suggests that bipedalism more than inconvenience is an

advantage for many reasons. He thinks many of the back pain issues are not related with

bipedalism itself but rather with our lifestyles. For example, fat people have a higher

probability of getting back pain than thinner people because their bodies have to support

a larger amount of weight, which they are not designed for. Additionally, Alfonso

argued that many of the back pain issues are directly related to longevity. People

nowadays live double and even triple the years compared to hominids, so it is common

sense to accept that the human machinery is way past its “sell by date” resulting in

many ailments, such as back pain, arthritis, cancer, etc.

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Morphological changes between chimpanzees and early hominids (Australopithecine).

5. Anatomical changes due to Bipedalism

Five to six millions years ago bipedalism as a new form of locomotion was adopted by

early hominids or Australopithecine, related to the Australopithecus. The reason as to

why bipedalism became a form of locomotion is proposed by several hypotheses but

with no definitive conclusion so far.

There are many anatomical differences between apes and modern humans. The first

hominids were very similar to today’s chimpanzees but as they started to stand up and

walk many morphological changes began to emerge. Bipedalism required a set of

anatomical changes to enable the support of the body weight and to maintain balance.

The most spectacular alterations are in the spinal column, the pelvis, the skull and the

feet. These changes were crucial to support and enable this new form of locomotion.

In the following sections the different anatomical changes humans have developed will

be considered.

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5.1. The skull

In order to walk upright and to increase the visual field the

skull needed to be attached to the spinal column in a better

balanced position. Now that the spine was straighter the

foramen magnum, which is the hole where the spinal cord

and vertebral column connect to the skull, was gradually

located more to the centre of the base of the cranium to

improve balance. In the diagram on the previous page there is

a clear difference between the connections of the spinal

column to the skull. In the case of the Australopithecine the connection is located in the

centre unlike in the case of the chimpanzees that have the spine connected at the back of

the cranium, holding the head at an angle. This transformation has helped to support the

weight of the cranium transferring much of it to behind the spine. It is a crucial

morphological improvement for the human lineage because it probably aided the

development of the brain and skull enlargement.

5.2. The spinal column

The spine changed from an arch-shape in chimpanzees to the shape of a “double s” in

humans. This change allows us to maintain balance in an upright position while moving

and keeping in sight surroundings. This transformation offers greater efficiency as it

requires less energy to maintain the spine in an

upright position.

It is important to keep in mind that as a result

of this development all the weight we would

probably be supporting on four legs we do

with only two. Another very interesting

observation that makes this change an

important in the evolution of bipedalism is the

fact that we can walk without transmitting too

much shock to the body. For every footstep we take the whole body weight is supported

by one of the limbs. The ground produces an equal and opposite reaction to the weight

bearing down with every step. Were the spinal column not to have evolved in this

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particular double-s way, the reactive force produced by the ground would create an

impact that would affect the entire skeleton.

The human spine has four main curves. The ones

that support almost all the weight and keep the body

erect are the lumbar and thoracic curve, which are

both located in centre of the torso. The thoracic

curvature is situated in the upper region of the torso

forming a backward bend and the lumbar curvature

in the lower region forming a forward bend both

completing an inverted “s”. The lumbar curve is crucial in allowing us to maintain

balance and to walk. This forward curve helps to keep the centre of gravity directly over

the feet and therefore allows us to maintain balance. In the past early hominids, who

still did not walk, had spines with an arched form making bipedalism not as efficient

and useful as it is to modern humans.

When observed the structure of the spine of the previous curvatures mentioned a big

difference stands out. These two curvatures have the biggest and thickest vertebrae and

intervertebral discs. This difference can also become a problem due to the fact that

these areas are the ones that receive greater stress and support more body weight.

The other remaining curvatures are the cervical curvature,

located above the thoracic curve, and the sacral curvature,

located below the lumbar curve. The cervical curve is

extended in the neck area and, therefore, its main purpose is

to support the weight of the skull. The sacral curve, however,

does not support much body weight. The main function of

this curve is to connect to the lower limbs and pelvic area.

An interesting insight in relation to this area is the fact that in

other animals it has much use. The ending of this part of the

spine is formed by what seems an undeveloped tail. This last

segment of the column, in most terrestrial animals, stretches and even adds more

vertebrae to form a tail that helps to maintain balance. The length of this tail varies

depending on how well balanced the body is. In the case of humans the need of a tail is

of not much use because we are already sufficiently well balanced.

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5.3. The arms

The arm structure hasn’t undergone many changes since hominids began to walk. The

main difference between modern human’s arms and their early ancestors is the fact that

arms were now no longer needed for locomotion and were used only for manipulating

objects. As a result, other changes took place. The scapula changed from a lateral

position to a dorsal position and the clavicle was bent forward to allow for greater

mobility in the forelimbs.

5.4. The pelvis

As a result of the study of pelvic fossils and the

pelvis structure of modern chimpanzees and

other apes, scientists have discovered that before

our ancestors stood up their pelvic structure was

very different. Primitive apes had a similar

pelvic structure to modern chimpanzees. As

these apes evolved and eventually started to

develop a bipedal stride their pelvis was

transformed strikingly as a result of the need to support weight and maintain balance on

two legs.

The pelvis is an anatomical structure that consists of four parts: two coxal bones, which

are called hipbones, located on each side of the lower torso and joined with a cartilage

disc (called symphysis pubis) forming the pubic area. These hipbones are connected

near the back to the sacrum

and its tail ending called

coccyx.

Each hipbone is formed by

three fused bones: the ilium,

the ischium and the pubis. At

birth these bones are separated

and within a few years they

fuse together forming a single

bone.

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When early hominids walked on four legs they had a different pelvic structure allowing

them to support strong muscles for climbing. This primitive pelvis may still be very

similar to the one found in chimpanzees and other apes.

The most remarkable attribute of primitive pelvises are their long narrow iliac blades.

These extend along each side of the sacrum in line with the spine. The structure of their

pelvises improved their way of moving through trees by attaching powerful climbing

muscles to the long iliac blades. Another characteristic of these creatures is a straight

narrow sacrum and coccyx.

The main difference that

sets apart these primitive

human pelvises from

modern ones are the

changes in the iliac blades

(ilium), which are part of

the hipbone.

Nowadays modern humans

have developed a pelvic

structure capable of supporting all the weight of the upper body and also, in the case of

females, capable of giving birth to babies with big skulls. This pelvic structure has

permitted the development of strong muscles, which allow humans the unique ability to

walk on two legs during long periods of time without wasting too much energy.

The modern human pelvis is much shorter than the primitive one but is wider forming

an efficient supportive system for bipedal locomotion. In this case, the ilium, which is

well connected to the sacrum, has a broader flattened blade extension coming out from

each side of the sacrum. This improvement provides stability and the ability to support

greater amount of weight using only two legs.

The reorientation of the ilium required two other changes, which were not a direct cause

of bipedalism. When the ilium rotated to support a greater amount of weight, another

problem arose. This was the need to hold together muscles and lower vital organs. For

29

this reason the sacrum, which separates the ilium at the back of the pelvis, has grown

wider and the ilium has changed its shape.

Underneath the ilium, the ischium and pubis are fused forming the pelvic structure. In

the ischium there is a crucial socket, called acetabulum that allows the femur to connect

and transfer the whole weight of the body to the legs. In the past this connection was

made further up on the ilium but as the femur needed to be connected in such a way that

it could support the weight of the torso and at the same time move, it needed to be

lowered.

Another important change was the flattening of the ischium that provided the ability to

be able to sit.

5.5. The Legs

The legs or hind limbs of all terrestrial animals are composed of three main parts, each

of which provides a crucial function to allow movement.

These are the femur, which is the most important bone for walking upright, and its

connections with the pelvis and the knee called hip and knee joint.

The shinbone is also part of the leg structure but it hasn’t suffered any significant

evolutionary change.

5.5.1. The hip joint

The hip joint is the connection between the

acetabulum and femoral head.

The main difference between the modern

human’s hip joint and the ones in early

hominids, who still did not walk, is that

humans need a larger hip joint to support

more body weight and to cope better with the

stresses produced while walking.

Previously, in the pelvis section, I have

mentioned that the acetabulum needed to be lowered to improve the support of the

weight of the torso during bipedal locomotion, but this adaptation was not the only one.

30

When early hominids started to walk upright there was a need to place the vertebral

column closer to the hip joints in order to provide a stable base for the trunk when in

motion.

In the diagram at the beginning of the section there is a clear difference between how

the body weight is situated. In the chimpanzee the body weight is more or less

distributed equally among the shoulder joints and hip joints. In the case of the

Australopithecine the weight of the trunk is placed above the hip joints, transferring the

whole body weight to these relatively unstable balls (femur head) and sockets

(acetabulum).

To solve this radical change there was a need to enlarge the hip joint so it could absorb a

greater amount of stress and accommodate a larger femoral head.

5.5.2 The femur

As mentioned in the previous section, when early hominids started to stand and walk

there was a greater amount of stress on their hip joints and femur.

The femur is the upper bone of the leg limb. It has three main components: the femur

neck, which is the long straight part, the head of the femur, which connects to the hip

joint and the distal end of the femur that articulates with the tibia and the patella

forming the knee joint.

Since bipedalism was adopted millions of

years ago the femur has suffered some

changes. There are two principal differences

between a femur of an Australopithecine or

modern human and one of a chimpanzee’s.

Human beings have a longer femur angled to

the midline allowing better support of the

body’s weight and to walk more efficiently.

Bipedalism created the need to balance the weight on only two legs. To do so the centre

of gravity needs to balance over each leg when walking. The femur, typical of modern

31

humans and early hominids, angles inwards so that the knee joints come closer together

placing the feet directly underneath the centre of gravity.

In the diagram at the beginning of this section there is a clear difference in how the

weight is distributed. In chimpanzees the weight is distributed evenly over four legs and

therefore there is not so much pressure on the hind limbs resulting in a straight femur

typical of the fully erect posture of terrestrial animals. In some occasions, they do stand

up but not as long as Australopithecines or modern humans.

5.5.3 The knee joint

The human knee joint has undergone similar changes to those concerning the hip joint.

With an increase of weight distributed on only two legs, the knees required more

support so they needed to be enlarged. The difference

between this lower joint is that because it is situated

almost directly under torso there is a greater amount of

pressure, thus knee joints are larger than the hip joints.

This adaptation provided a set of changes that would

make bipedalism more efficient. Now when walking

upright, the degree of knee extension is less in

comparison to that found in four legged animals.

Humans walk with their knees almost straight and, as a result, their function for this

action is to provide weight support.

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5.6. The feet

The adaptation of the feet to bipedal motion changed drastically their function and

structure. The main difference between the foot of a chimpanzee and an

Australopithecine is the size and shape. These factors are determined by the function

they serve. In the case of chimpanzees they need four broad hands and feet to be able to

walk but at the same time climb or grab food. When early hominids started to walk

upright, their feet developed over time the unique and principal functions of supporting

and stabilizing the whole body leaving the hands free for other activities. To fulfill this

purpose, the feet needed to develop a wider and

flatter structure that could act as a supportive

platform.

A foot is an incredibly complex mechanism. It

is composed of three main groups of bones: the

tarsal bones, the metatarsal bones and the

phalanges. The most important bones to be

considered are the talus and calcaneus bones,

which connect to the lower region of the leg

forming the heel, and the hallux or great toe,

which is crucial for propulsion.

The human foot has developed very important

attributes as a result of bipedalism. Now that there

was no need for grasping or grabbing, the toes lost

this ability and decreased in size. The same happened

to the diverged big toe or hallux. It was gradually

centred in line with the other toes but it maintained a

larger size in comparison to the other toes.

Other very important features, which contribute to the

propulsive system of bipedalism, are the foot arches.

In modern humans, these arches are larger providing a

more stable platform for the body.

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5.7. Muscular changes

When hominids started to walk, not only did bones adapt but also muscles. To support

this new way of movement the muscular organization needed to be changed. Two

important muscles, which in the past which were used in leg movement, called Gluteus

Medius and Gluteus Minimus evolved to serve as abductor muscles. The purpose of

these muscles is to help stabilize the body.

Also, when the femur length increased, the leg muscles responsible for motion were

modified. Each footstep a human takes the leg muscles situated at the ankle have to

propel the whole body weight. When we are about to take the next footstep there is not

as much muscle activity due to the fact that a longer leg provides a natural swing.

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6. The consequences of upright posture

Over the last few millions years humans have benefited from all the advantages

resulting from walking upright. We have been able to walk and run without wasting too

much energy; we have been able to create and manipulate a diverse array of tools to

improve life; we have been able to give birth to babies with large brains; and maybe

even walking upright has been responsible for promoting brain enlargement! But not all

is good news; there is a price to pay for walking they way we do.

A great number of problems arise as a direct consequence of standing up and walking.

Even though we are able to stabilize our bodies correctly our feet will ache and we will

injure our knees during our lifetime. Back problems are another important source of

injuries. We can twist and bend our spines while keeping our balance but yet we all

suffer from back problems at some stage in our lives. These painful consequences are

almost unavoidable.

6.1. Facts and statistics

It is important to keep in mind that the dates, which these facts and statistics refer to, are

of no great importance. What really stands out is the sheer magnitude of the numbers

both in human and economic terms that are directly related to back pain.

In the following sections I will consider facts and statistics from the United States,

Europe and Catalunya.

United States

According to the American Chiropractic Association, the Agency for Healthcare

Research and Quality, the Oprah Magazine, and to the Journal of the American Medical

Association:

• Lower back pain is the principal cause of work disability worldwide.

• Back pain is one of the most common reasons for sick leave. In fact, back pain

is the second most common reason of visits to the doctor’s surgery.

• Most cases of back pain are mechanical in origin, meaning they are not caused

by serious ailments, such as inflammatory arthritis, infection, fracture or cancer.

• Back pain is one of the most costly health problems in society. In 2005 care

costs reached $85.9 billion (109). According to the AHRQ, in 2007 a total of

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$30.3 billion was paid to providers, such as doctors, physical therapists and

others, as well as to pharmacies. Americans spend at least $50 billion each year

dealing with back pain issues. In total, spine treatment is a part of the $2.2

trillion (1012) healthcare industry.

• Experts estimate that 60% to 80% of the population will experience back

problems at some time in their lives. In 2007 alone, about 27 million US

adults aged 18 or older (11% of the total adult population) reported having

back pain.

• The 2008 survey presented by the Journal of the American Medical Association

asked a sample of approximately 23,000 people with and without back problems

about how much their medical costs were. Individuals with back or neck

problems spent on average $6090 in 2005, whereas healthy people’s medical

cost averaged $3056 in the same year.

Europe

According to the European Commission and the University of Oslo:

• Every month around 50% of Europe’s population report some kind of

musculoskeletal pain.

• Population surveys show that back pain is the most common type of pain in

young and middle aged adults, whereas knee pain is more common in older

people.

• The most common cause of sick leave and long term work disability in

individuals of working age is back pain and widespread chronic pain. This is

clearly a serious problem for those affected individuals and the resulting

economic cost for society is enormous.

• Rheumatic disorders, related to pain or disability of the musculoskeletal system,

represent nearly 25% of the Europe’s public healthcare budget.

“Musculoskeletal Problems and Functional Limitation” European Commission; Oslo,

October 2003.

36

Catalunya

According to the Generalitat de Catalunya and to l’Enquesta de salut de Catalunya

(ESCA 2006/ 2012):

• Rheumatic disorders are the leading cause of chronic pain. The most prevalent

ones are back pain and osteoarthritis.

• In 2005 29,6% of the population were reported to have suffered from back

pain –lumbar or dorsal-, 27,6 % from neck pain and 22,6% from osteoarthritis,

arthritis or rheumatic disorders.

• In 2007, these disorders were the second leading cause of work disability, which

led to 238.356 cases of long term work disability. This represents 20% of the

total and the principal cause was lumbar pain.

• In 2012 76,7% of the population from 15 years old and onwards is suffering

or has suffered some chronic ailment. The principal ailments are related to

illnesses of the musculoskeletal system (lumbar and dorsal pain, osteoarthritis,

arthritis or rheumatic disorders) and illnesses of the circulatory system (High

blood pressure, cholesterol, Varicose veins in the legs or bad blood circulation).

A precise breakdown between the two families of chronic ailments is unknown,

however it is clear from the numbers that it is a significant problem regardless.

• Back problems, migraine and allergies are the most frequent ailments found in

the age group between 15 to 44 years old. From 45 years onward this tendency

changes to back problems, osteoarthritis, arthritis and rheumatic disorders.

“Dia Mundial contra el Dolor” Generalitat de Catalunya- Canal Salut. 17/10/2008

“Enquesta de salut de Catalunya 2012” -Generalitat de Catalunya- Maig 2013

6.2. Healthcare professional’s opinions

I have had the opportunity to interview two professionals related to the healthcare

world. From all the facts and data I have seen and from all the anatomical changes and

hypothesis that I have studied I prepared a few questions for them to answer.

37

6.2.1. Postural re-education specialist

The first expert I interviewed was Ester Sánchez González, a professional in postural re-

education. She answered a few questions that I had prepared for her in relation with

bipedalism and postural re-education. I was interested in having a professional’s point

of view on the development of the upright posture, which eventually would evolve into

bipedalism, and how this relates to back problems.

Ester believes the reason that made hominids adopt habitual bipedalism, although still

uncertain, was out of pure necessity, in other words, to survive. However she is

convinced that bipedalism requires much more effort than quadrupedalism and therefore

believes there had to be some selective pressure that made hominids adopt upright

walking.

When early hominids started to stand up and walk there was a set of anatomical changes

that needed to be acquired. Ester suggests that hominids little by little started to walk

and, in time, the muscles, which were responsible for maintaining the body upright and

permitting bipedal motion, became more adapted and therefore more efficient. Finally,

although these changes occurred over millions of years, the skeletal structure changed in

shape and position. During this period of time, Ester suggests that back problems were

not a big issue due to the fact that hominids alternated between walking upright and

walking using four legs so there wasn’t too much pressure on the back. This was also

because hominids still showed signs indicating that they had their knees flexed and their

pelvises still perpendicular, therefore the bodyweight wasn’t placed directly over the

back and legs but over a more forward position. She mentions that, in the beginning,

their backs were in kyphosis meaning they still conserved their curved spines and while

upright they walked similar to a hunchback.

As mentioned before, these ape-like characteristics changed with time. Nowadays when

modern human beings stand and walk upright the posterior muscle chain, which is a set

of muscles that, in spite of being separate, work as a whole, shortens, exaggerating the

physiologic curve of the spine. Therefore she agrees that we aren’t meant to walk.

As outlined in the section Facts and Statistics, the leading cause for work disability is

back pain and specially lumbar or lower back pain. This happens because if the pelvis is

38

not well positioned, the whole weight of the torso is placed on the lower part of the

spine, specifically between the L5-S1 vertebrae. The pelvis loses its ideal position

because the lumbar and dorsal muscles in charge of balancing the pelvis are being used

to hold the upright posture. Consequently the pelvis is moved backwards and the lumbar

column is curved resulting in the compression of the vertebrae and intervertebral disks

and an exaggerated lumbar curvature that will lead to future pain.

Ester agrees that most of these flaws in our design that lead to pain are related to our

modern lifestyle. Humans have adopted new habits in a relatively short period of time.

People nowadays are more sedentary and do not need to hunt or gather food and they

also have comfortable furniture. This “easy life” is responsible for shortening even more

the posterior muscle chain, which is in charge of holding the body up, and consequently

increasing the possibilities of having back pain.

When the human body is upright it will always need to shorten the posterior muscles

leaving the anterior muscles relaxed. This is not the only case, muscles work as

antagonists when executing an action, some muscles will extend while others will relax.

Ester proposes a solution based on some of these previous facts. She suggests that if

these shortening muscles were continually relaxed as a result of stretching the muscle

chain, the back wouldn’t suffer as much pain.

Ester makes a very interesting observation in relation to lifestyle. In the so-called

underdeveloped primitive societies back problems are not so prevalent because they

exercise much more their bodies. Ester suggests that if modern urban humans lived in a

more “natural” and active way they wouldn’t have so many back problems.

She told me an anecdote, which was very curious. The fact that human babies learn to

walk upright is strictly related to them copying the way their parents walk. Imagine the

case where a family of gorillas raises a baby, he will copy their way of moving,

although anatomically the baby would be prepared for bipedalism.

39

6.2.2. Orthopaedic doctor

During the time I spent in Munich working with my uncle, in a specialist medical

practice, I saw many people suffering from orthopaedic problems. Surprisingly, back

related problems in the spine and the surrounding muscles were the most common,

followed by injuries in the knee and shoulder joints. Another frequent problem was pain

related to the feet and degenerative processes in the hips.

All of these observations made me realize there had to be some link between some of

these "syndromes", pains and injuries and the fact that we are probably not supposed to

walk upright, or at least not finished evolving to do so adequately.

I prepared a few questions related to this matter for my uncle, Dr. med. Erich Koller,

orthopaedic specialist, to give his professional opinion.

Erich normally sees all kinds of injuries and pain-related syndromes. These are due to

traumas resulting from the practice of sports, daily life and domestic accidents. From his

experience, the most common pain syndrome is back pain. This is caused by all sorts of

injuries normally related to lifting weight incorrectly, bad walking habits, sitting for

long periods of time, bad postures during sleep, etc.

He suggests that walking upright may be the cause of back-related problems, however,

he highlights the effect of the modern lifestyle to the human body. He also agrees that

our bodies are meant to move and walk, so spending a lot time sitting without

exercising our bodies will eventually lead to problems in the skeleton, joints and

muscles. Erich also adds that excess weight is another big issue that causes many of the

problems, syndromes and pains mentioned previously.

Erich asserts that there is no quick solution to this problem; bipedalism has taken

millions of years millions to evolve and therefore to improve even more, millions more

years will have to pass. From his professional point of view he suggests that exercising

regularly, muscular training and stretching at least once a day will reduce most of these

pains. He also suggests that by walking with the right footwear these pains will be

reduced. Furthermore he recommends that preventing being overweight and obesity will

also reduce the number of people suffering back pain.

40

Erich proposes a possible modification to the body to improve its stability and reduce

back problems. He suggests that stabilizing the spine and knees, along with reinforcing

the muscles in the gluteal and hip area would be of great help when walking upright.

To sum up, Erich recommends that by being cautious and aware of the bad habits, such

as sitting all day long without moving, a lot of the problems regularly seen in his

medical practice would not occur.

41

7. Conclusions

Back pain is one of the most common ailments in modern societies. This results in a

great deal of pain for those who suffer it and has huge economic consequences.

As a result of the study of different aspects of the human evolutionary journey to

bipedalism and with the help of a professional of the subject matter I have come to the

following conclusion. The evolution of human locomotion experienced a drastic

divergence in relation to all the other members of our ape family. We managed to

develop an upright stance, walk and become efficient at it. Therefore, bipedalism more

than an inconvenience offered our human ancestors a great evolutionary advantage.

My initial objective was to establish a relationship between back-related ailments and

the way we walk. Thanks to the help of two professionals in the healthcare world and

after analysing the principal anatomical changes the human lineage suffered while

adopting bipedal locomotion I learned something very interesting. As mentioned before,

bipedalism served as an advantage during millions of years for our ancestors; but were

they or we properly adapted to support this form of locomotion? The truth is that we

aren’t meant to walk but it is to late to turn back, evolution made our decision for us

millions of years ago. However there is a bigger problem, which directly affects back

pain. Modern human lifestyles in conjunction with longevity exacerbate the underlying

design flaws of our bodies. Nowadays people live twice or even three times the years

compared to their ancestors. We also have no need to hunt or gather food so there is no

real pressure or need forcing us to move our bodies. Furthermore, comfortable furniture

and excess weight are factors responsible for increasing the number of sufferers of back

ailments.

Many of these problems are clearly and directly related to lifestyle. Modern urban

societies have great healthcare services, which permit us to live longer. Food

availability in nearly every corner of every town makes the task of hunting and

gathering food obsolete. Cars, motorbikes and public transport fulfil for most people the

necessity of transportation and so the general level of daily exercise of an individual is

minimal. In other words, people do not move anyway nearly enough to maintain a

healthy body and are becoming lazy.

42

Most aspects of the modern lifestyle are relatively beneficial for human beings but some

of our habits would need to change in order to reduce the great number of people

suffering from back pain. In order to improve this situation people should increase the

amount of exercise in a practical way that complements their daily routines. Simple

activities such as walking or cycling to work could make the difference between a

healthy and an unhealthy body.

The part of country’s healthcare budgets dealing with back pain costs billions of dollars

and euros. We visit regularly doctors, physiotherapists and chiropractors and spend a lot

of money on “repairing ourselves”. So this poses the question, what are governments

doing to resolve this problem? If only a fraction of the money spent on doctors and

pharmaceuticals were to be used in making people aware of the long-term consequences

of these bad habits, the number of sufferers would be reduced significantly. One

practical solution could be to educate children from an early age about being aware of

our design flaws and their direct long-term implications and promoting good lifestyle

habits to avoid future potential problems. This approach focuses specifically on back

problems but similar initiatives would also be very effective in dealing with, for

example, obesity. This could be achieved by teaching young children how to adopt and

maintain a proper and healthy diet.

I wonder if solving these problems is in the interest of everyone. Chronic diseases and

ailments provide drug companies and businesses related to the healthcare world with

huge incomes every year. So, are they really interested in solving the problem or are

they more interested in their profits? It is clear that the political will to implement long-

term beneficial preventative medical strategies through education is not evident and is

not a priority in our society for some reason!

43

8.1. Annex 1: Transcript of the interview with a Postural re-education

expert

I have prepared a few questions related to this subject for Ester Sánchez González,

professional in postural re-education, from the Centro de Colocación Postural Activa.

Although the interview was conducted in Spanish there is a section in which I explain

the most important observations and key ideas.

1. En relación al desarrollo de la bipedestación en los bebés, ¿Crees que los

primeros homínidos que llegaron a erguirse sufrieron los mismos problemas que

los seres humanos actuales? “La evolución hasta la posición erguida debió de pasar

por muchas fases y necesitar de muchísimo tiempo. No creo que fuese un cambio

brusco, sino paulatino y que estos primeros homínidos alternarían el ir avanzando en

dos patas con la marcha en cuadrupedia o casi cuadrupedia típica de los primates, que

se ayudan de los nudillos de sus manos para avanzar. Debió de ser un cambio muy lento

que por tanto, al no estar totalmente establecido, no produciría tanto acortamiento en sus

cadenas posteriores. Los primates descansan sobre sus patas posteriores pero se ayudan

con sus nudillos y sus piernas están flexionadas, por tanto los músculos de la cadena

posterior no están en tensión para aguantar la posición. Si las rodillas están flexionadas,

no podemos hablar de una contracción de la cadena posterior ni de músculos estáticos

como en el caso de los seres humanos actuales, que al tener que sostener el cuerpo en

dos piernas y mantener su equilibrio en ellas toda su cadena posterior está en tensión

para que se produzca el equilibrio. En el caso de los primeros homínidos, su peso se

desplazaba todavía demasiado hacia adelante, la cadera todavía no se había puesto

perpendicular y por tanto, su espalda estaba en cifosis, todavía no habían aparecido las

curvas fisiológicas, supongo, y por tanto, el eje estaba desplazado hacia adelante.”

2. Ya me contestaste a mi pregunta sobre si estábamos diseñados para caminar.

Me explicaste que el cuerpo humano, al erguirse debe acortar la musculatura

posterior exagerando la curvatura fisiológica de la columna. Entonces, si no

estamos diseñados para caminar, ¿Crees que este cambio tan radical fue un

cambio evolutivo (Darwin)? ¿O tuvieron que adoptar esta exageración muscular

para poder sobrevivir? (Teoría de la Savannah, Teoría del calor, etc.) “A esto no te

puedo contestar. Hay tantas teorías que te darían buenos argumentos para defender la

44

posición de Darwin como la Teoría de la Savannah. Yo creo que caminamos porque no

nos quedó más remedio. Lo que sí sé es que requiere mucho más esfuerzo caminar que

estar en cuadrupedia, como requiere mucho menor esfuerzo reptar que avanzar en

cuadrupedia. ¿Por qué dejamos de reptar y empezamos a avanzar en cuadrupedia?

Supongo que porque no quedó más remedio. Las especies, como sabemos, mutan por

pura necesidad y las que no mutan desaparecen. En cierto sentido, dejar de ir en

cuadrupedia y caminar en dos piernas fue una especie de mutación. ¿Por qué sucedió?

¿Por el calor? ¿Porque no había suficiente comida en los árboles para todos?”

3. Como dice Mèzierés: los músculos deforman los huesos y no al revés. ¿Estás de

acuerdo en que los primeros cambios anatómicos que los primeros homínidos

sufrieron fueron cambios en la musculatura (en concreto en la cadena posterior)?

“Creo que debió de suceder de esta forma: primero, cambiaron los hábitos de caminar,

moverse, etc.; después tuvo que adaptarse la musculatura a estos cambios y, finalmente,

los huesos tuvieron que cambiar su plano. Esto que parece tan increíble sucede

contínuamente en procesos naturales como por ejemplo el embarazo. Como sabemos, el

cuerpo de una embarazada sufre cambios posturales. El hecho de que el feto vaya

creciendo y ocupando espacio hace que el cuerpo de la mujer sufra cambios en su

pelvis. Además, estos cambios son necesarios para favorecer el canal del parto con lo

que la columna lumbar se deforma y se crea una hiperlordosis lumbar, un arco

exagerado en la columna lumbar. Pero la hiperlordosis es fruto de la necesidad de que el

feto debe salir por la pelvis, con lo que esta sufre un cambio, una anteversión.

Esto es una prueba más de que no estamos preparados para caminar erguidos. Las

hembras de otras especies mamíferas no tienen tanto problemas a la hora de parir a sus

crías. Además, la posición horizontal de su tronco favorece la protección del feto y su

expulsión. La piel en otras especies mamíferas está recubierta por pelo y una piel más

dura, mientras que en la parte anterior están los órganos vitales, y la piel es mucho más

suave y blanda. Pero resulta que en otros mamíferos el cuerpo al estar en cuadrupedia o

pseudocuadrupedia, como en el caso de los primates mayores, protege esos órganos

vitales, esa parte blanda queda protegida por el lomo de piel dura y por la posición,

mientras que en los humanos la parte anterior del cuerpo queda tan desprotegida como

la posterior, por tanto, tal vez todavía estamos en un proceso de mutación y falten

algunos cambios posturales por suceder.”

45

4. ¿Todos los problemas de espalda (en general) se deben al acortamiento de la

cadena posterior? ¿Crees que habría alguna forma de arreglar este problema,

aunque significara volver a caminar a cuatro patas? “Una vez adaptado un cambio

no se puede ir hacia atrás. El coste de ir erguidos ha significado dolor de espalda, pero

la ganancia ha sido importante: hemos sobrevivido como especie. Hay diferentes

cadenas musculares, la más importante en número de músculos es la posterior, pero el

acortamiento de otras cadenas musculares también afecta a la deformación del

esqueleto: por ejemplo, el acortamiento de la cadena lateral también provoca

alteraciones en la cadera. Además, los acortamientos en una cadena afectan

invariablemente a otras cadenas y favorecen su acortamiento.

Debido a mi trabajo, puedo decir que una solución es liberar contínuamente estos

acortamientos a base de estiramientos de las cadenas musculares, puesto que el cuerpo,

debido a su posición erguida, va a tender siempre a acortar los músculos de la parte

posterior y a dejar “fofos” los músculos de la parte anterior del cuerpo, porque así

funcionamos: los músculos funcionan como antagonistas y si un músculo de atrás se

tensa el de delante se pone “fofo”.”

5. Tuve la oportunidad de poder ver a varios pacientes en la consulta de mi tío,

especialista en ortopedia, que sufrían de dolores de espalda (donde más en la zona

lumbar) debido principalmente a malas posturas, esfuerzo físico, etc. Ocurre lo

mismo en tu área de trabajo? “Sí, es cierto, los dolores lumbares son los más

frencuentes debido a que todo el peso corporal recae entre las vérbrebras L5-S1 cuando

la pelvis no está bien alineada. Y la pelvis pierde su colocación “ideal” debido a su vez

a que nuestros músculos lumbares y dorsales necesiten estar en tensión para aguantar la

posición erguida. Esto provoca que la pelvis vaya hacia atrás y se curve la columna

lumbar, a que las vértebras se junten más y se curve de forma exagerada la columna

lumbar.”

6. Dejando a un lado los problemas de espalda. ¿Por qué hoy en día se sufren

tantos problemas musculares (relacionados con malas posturas)?¿Crees que la

gente en general debería mejorar su postura mientras caminan, están de pie y

hasta cuando duermen o se sientan? “Nuestros hábitos de vida y alimentación han

cambiado mucho en muy poco tiempo. Hacemos vidas más sendetarias, no necesitamos

46

ir a cazar para comer, hemos incorporado mobiliario que no hace sino favorecer aún

más el acortamiento de nuestros músculos. Hay sociedades, las mal denominadas menos

evolucionadas o primitivas, que no tienen tantos problemas de espalda: caminan

descalzos en suelos blandos que se adaptan a sus pies, se sientan en cuclillas para

charlar o comer, duermen en una especie de colchones a ras del suelo... Nuestros hábitos

han favorecido aún más si cabe nuestros acortamientos. Una vida más activa y más

“natural” haría que no tuviéramos tantos dolores de espalda, por no hablar de los

zapatos de tacón en las mujeres. Lo último que he escuchado es que un cirujano ha

tenido la brillante idea de amputar los dedos meñiques de los pies de las mujeres para

que éstas puedan calzar un zapato stiletto de un diseñador muy famoso de zapatos.

Según este “eminente” cirujano el dedo meñique de los pies no tiene ninguna función y

por tanto puede amputarse perfectamente. ¿Tal vez las próximas generaciones nazcan

sin ese dedo? No lo sé, pero tengo muchísima curiosidad por saber qué pasará con uno

de nuestros pilares básicos en la sustentanción del peso corporal, el metatarso del dedo

meñique con el dedo meñique incluido, por supuesto, y en cómo afectará este hecho a

nuestra colocación postural futura, de imponenerse el cambio tipo pandemia.”

7. Un poco por curiosidad. Dejando al lado la ley cefalocaudal. ¿Crees que un bebé

conseguiría una posición bípeda sin ninguna ayuda externa? ¿Si es así el caso, por

qué razón necesitaría desarrollar ese nueva forma de locomoción? “Sí que

conseguiría la posición erguida, tal vez con mucha más dificultad y tal vez con algunos

pequeños cambios al principio, pero como viviría en una sociedad donde todo el mundo

a su alrededor camina de forma erguida sólo por imitación podría erguirse. Ahora bien,

si un niño se criara con primates caminaría como ellos, aunque en potencia pudiera

caminar erguido.”

Otras preguntas

· Cómo se desarrolla la locomoción bípeda desde el nacimiento? “Siempre va desde

la cabeza hacia abajo: ley cefalocaudal. Lo primero que erguimos es la cabeza, el bebé

fortalece el cuello para poder erguir la cabeza, luego la musculatura dorsal, apoya los

brazos y los estira, después las piernas, debe fortalecerlas, debe gatear también para

aprender la marcha en cuadrupedia, finalmente se pondrá de pie.”

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· En un futuro: ¿la evolución muscular (o del esqueleto) mejorará el diseño

anatómico? “Yo creo que hablar de mejoras es mucho decir. Se ha hablado siempre de

un cráneo cada vez mayor y de que desaparece lo que no se usa o no se cree

imprescindible. Lo que sí percibo en las personas que acuden a mi Centro de

Colocación Postural Activa es que los dedos de los pies cada vez tienen una menor

movilidad debido a su poco uso. Puede que en un futuro no muy lejano los dedos dejen

de moverse y esto provoque cambios significativos en nuestras caderas.”

· Qué sería más beneficioso: ¿caminar o dejar de caminar? “En cuestión evolutiva

no siempre gana lo más beneficioso, gana lo que requiere un menor esfuerzo. Sólo que

si no hay opción: o morir o continuar erguidos, gana ir erguidos. De igual forma, si

nuestra supervivencia no está en juego, o no lo percibimos así, yo creo que ganaría no

caminar, porque nuestro cerebro no entiende que es más beneficioso caminar por la

salud, etc.”

8.2. Annex 2: Transcript of the interview with an Orthopaedic

specialist

Here below I have prepared a few questions related to this matter for my uncle to give

his professional opinion, Dr. med. Erich Koller, orthopaedic specialist.

1. From your experience, what is the most common injury or pain that people

suffer from? "We normally see all kinds of injuries and pain-related syndromes, due to

traumas in sports, daily life and because of accidents in the household. But the majority

of these are injuries in the knee/ankle area, followed by shoulder/hand accidents. The

most common pain syndrome would be the "back". All sorts of spine problems, due to

lifting incorrectly, bad walking habits, sitting for long periods of time, bad postures

during sleep, and so on. Then we have all kind of muscle stiffness from top to bottom.

Most in the hip and gluteal region, including hamstrings."

Do you think it is related to the fact that we haven’t successfully evolved for

bipedal motion? "Yes you could think so, I wonder if evolution still has not completed

the shaping of the human body concerning bipedal motion. We see way to many

48

problems with the back, spine, hip and knee joint, also trouble with feet and muscles.

But on the other side life and surroundings have changed so much over the last centuries

and decades that our body doesn't seem to fit into it appropriately enough.

Even if it doesn't look so at first sight our body is made for moving and walking! We

were designed to move around in nature at first hand."

"You see, we spend most of our time sitting: from home to work (bus/train/car), at work

(normally in front of the computer and/or at a desk), same on the way back, and finally

home - back to the chair or sofa again (PC, laptop, PlayStation, TV).

In general we do not move enough, that leads to a lot of problems in the skeleton, joints

and muscles.

Another issue is weight, better said overweight, causing many of the above mentioned

problems, syndromes and pains."

2. Could you suggest a solution to this problem? "Unfortunately there is no quick

solution to evolution (may take too long), but we (mankind) may develop further or

towards more sitting - who knows?

But from my point of view, the solution would be to move and exercise regularly,

people must do physical exercise, muscular training and stretching at least once a day.

This will also prevent or reduce cardiovascular risks, such as heart attacks, high blood

pressure or strokes.

All types of moving, using our body skills will help: walking, stretching, gymnastics,

swimming, biking, and so one. Not to talk about preventing overweight and obesity,

which are responsible for a lot of our daily problems in the practice too."

3. Should the appropriate musculature be improved or reshaped in such a way

that injuries resulting from walking are reduced? "Yes, as mentioned before, it is

important to move regularly to use your muscles and built up strong structures in order

to prevent damages and injuries. The use of the skeleton and the muscles (e.g. less

sitting) would improve many peoples back problems and avoid injuries."

Or should the skeleton be modified for the same purpose? "Well the problem is

rather that the skeleton has already changed over the last centuries. People in general are

growing taller, so the pivots and shifts on joints and the spine have definitively

increased, you can’t change that.

49

If possible, a better stabilisation of the spine and knees would help, along with

reinforcing the muscles in the gluteal and hip area. Walking is a good thing to do (avoid

using the escalator, lift and car) - if you do it right. Start slowly and - in order to do it

properly, walk with the right type of shoes."

4. Ultimately, if none of those suggestions proved to be successful, would you agree

that unless we change our form of locomotion these injuries are inevitable?

"In general injuries are unfortunately inevitable (sports, motion). You know, you walk -

even home, slip and fall or by doing so, just pull a muscle. There you go with an injury.

If we have more precaution and get people to be aware of their bad habits, e.g. get rid of

driving/sitting all day, then you avoid a lot of problems we see on a regular basis in the

orthopaedic daily life.

Or that our daily life changes to such an extent in the future that we drive and sit all day

anyway, being served by automats, just like in science fiction movies, then you would

avoid injuries!"

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9. Bibliography

Websites

· http://en.wikipedia.org/wiki/Animal_locomotion

· http://en.wikipedia.org/wiki/Terrestrial_locomotion

· http://www.geol.umd.edu/~jmerck/bsci392/lecture11/lecture11.html

· http://en.wikipedia.org/wiki/Bipedalism

· http://en.wikipedia.org/wiki/Laetoli

· http://en.wikipedia.org/wiki/Lucy_%28Australopithecus%29

· http://humanorigins.si.edu/human-characteristics/walking

· http://en.wikipedia.org/wiki/Ardi

· http://en.wikipedia.org/wiki/Orrorin

· http://emmagray.hubpages.com/hub/The-Many-Theories-Behind-Human-Bipedalism

· http://old.richarddawkins.net/articles/645378-study-reveals-why-our-ancestors-

switched-to-bipedal-power

· http://anthro.palomar.edu/hominid/australo_2.htm

· http://www.elucy.org/

· http://emmagray.hubpages.com/hub/How-Bipedalism-Has-Affected-The-Human-

Skeleton

· http://humanorigins.si.edu/research

· http://www.waterside-

hypotheses.com/UploadedFiles/Wading%20Paper/Supporting%20Files/model/s5_1_1.h

tml

· http://johnhawks.net/weblog/topics/bipedalism/why_be_bipedal.html

·http://www.maropeng.co.za/content/page/bipedalism_the_ability_to_walk_on_two_leg

s

·http://digitalcommons.iwu.edu/cgi/viewcontent.cgi?article=1013&context=socanth_ho

nproj

· https://en.wikipedia.org/wiki/Human_skeletal_changes_due_to_bipedalism

· http://en.wikipedia.org/wiki/Pelvis

· http://www.reasons.org/articles/the-leap-to-two-feet-the-sudden-appearance-of-

bipedalism

· http://anthropology.civilsprep.in/skeletal-changes-man/

51

Facts and Statistics

United States

· http://www.acatoday.org/level2_css.cfm?T1ID=13&T2ID=68

· http://backandneck.about.com/od/medication/a/Back-Pain-Prevalence-And-

Statistics.htm

· http://www.oprah.com/health/A-Cure-for-Back-Pain-The-Alexander-Technique

· http://meps.ahrq.gov/mepsweb/data_files/publications/st289/stat289.shtml

Europe

·http://ec.europa.eu/health/ph_projects/2000/monitoring/fp_monitoring_2000_frep_01_

en.pdf

Catalunya

·http://www20.gencat.cat/portal/site/canalsalut/menuitem.f039fb68a4311aec48af8968b0

c0e1a0/?vgnextoid=6daa590e7231d210VgnVCM1000008d0c1e0aRCRD&vgnextfmt=

detall&cod_noticia=94847&vgnextchannel=6daa590e7231d210VgnVCM1000008d0c1

e0aRCRD

·http://www20.gencat.cat/docs/canalsalut/Minisite/ObservatoriSalut/ossc_Dades_estadis

tiques/Estat_salut_estils_vida/Informacio_general_enquestes_salut/Enquestes_salut/Fitx

ers_estatics/Enquesta_salut_2012_edicio_maig.pdf

Books

· SLOAN, Christopher. La història de l’origen de l’home. 2004

· BOYD, Robert; SILK, Joan. B. Cómo evolucionaron los humanos. 1901

· CAMPBELL, Bernard. Human evolution. 1985, 1998