Issue 15 | January 2012

Growing bone

Exercise, Energy and Movement

***Articles reviewed and updated in August 2016***

All living things move. Whether it’s a plant growing towards the sun, bacteria swimming away from a toxin or you walking home, anything alive must move to survive. For humans though, movement is more than just survival – we move for fun, to compete and to be healthy. In this issue we look at the biological systems that keep us moving and consider some of the psychological, social and ethical aspects of exercise and sport.

Browse through the individual articles and check out our discussion questions and lesson ideas. We’ve also picked out content from other issues that we think is especially relevant. This issue was first published in 2012; in 2016, all of the individual resources were reviewed and updated for accuracy and currency. Please do note, however, that the PDFs of the original 2012 issue, infographic and poster have not been updated.

Made to move

From four legs to two

Why did humans evolve to be bipedal?

Adjusting to life on two legs

What changed when we began to walk on two legs?

Out of this world

Long-term low gravity can seriously affect the human body

Walk like a man

What steps are involved in walking?

Moving figures infographic

A numerical look at exercise, energy and movement

Muscles and movement

Types of muscle

Our bodies contain three main types of muscle

A closer look at skeletal muscles: muscle fibres

Skeletal muscles are made up of two groups of muscle fibres, adapted for different functions

How do muscles contract?

What causes muscle contractions?

Wasting away

Why diet, injury or a lack of use can all affect your muscles

Involuntary movement

Why do we sometimes move without meaning to?

Making muscles

How to build muscle

Exercise and the heart

The heart is a muscle, which can grow with exercise

Feeling sore

Why might exercise leave us sore?

Animation: Sliding filament theory

Watch or download our animation showing muscle contraction and the sliding filament theory

Bones and the skeleton

Bare bones

A look at what our skeletons do

Video: Bone biomechanics

Watch or download our video of biomechanics expert Dr Sandra Shefelbine as she uses elaborate models and her own body to explain arm movement

Factors affecting bone strength

How can our diet and exercise regimes affect the strength of our bones?

Thinning bones

Age, diet and exercise can contribute to thinning bones

Breaking bones

Even healthy bones can break if exposed to great enough forces


Learn to breathe

A look at how breathing is controlled

Take a deep breath

How do we measure how much oxygen we can use?

Step in time

Why feeling the rhythm can help you keep running

Something to say?

Is our move to two legs linked to our ability to speak?

Respiration and energy

Cellular respiration poster

Download a copy of our poster on respiration


Explore the structure and function of our intracellular energy factories


Take a look at the opening stages of cellular respiration

Aerobic respiration

A closer look at the reactions following glycolysis, should oxygen be available

Anaerobic respiration

The processes of anaerobic respiration differ between animals and plants

Energy is money

This illustrated analogy uses money to show how bodies store different forms of energy

Fit in mind and body?

Everything in moderation?

What do we need to do to be healthy?

Wearing out

Is the future of bone and cartilage replacement to grow your own?

Under strain

Why extreme exercise can be harmful

Psychology in sport

How your thinking can affect performance

Mental health and exercise

How exercise can change our mental state

Location, location, location

Does it matter where you exercise?

Fitness tests

This video by Tom Warrender of Classroom Medics examines body fat and VO2 max tests

Ethical questions

Performance-enhancing drugs

Explore current and future scenarios around controlled substances in sport


Exploring current and future scenarios around artificial body parts in sport

Physiological limits

Can we predict an ultimate limit to human performance?

Diet in sport

Exploring a current and future scenario around diet in sport

The placebo in performance

A look at the placebo effect in performance

Fitness fads

A look at different exercises that have become the latest craze in keeping us healthy

Video: Exercise mythbusting

How much should we exercise? Why do muscles get sore? Are fitness drinks worth it? Find out the answers to these questions and more in this short video

Real Voices interviews

Real Voices interview: Dr Jennifer Morgan

Meet Jennifer, a cell biologist at University College London

Real Voices interview: Ellie Simmonds

An interview with Ellie Simmonds – Paralympic swimmer and five-time gold medallist

Real Voices interview: Mark Bawden

Meet Mark, a sports psychologist who has worked with the England cricket team

Activities and lesson ideas

Further resources and activities on exercise

The Wellcome Trust has funded many organisations to produce activities and resources to engage and educate young people about the science of exercise

Fast Facts

Each issue of 'Big Picture' comes with a sprinkling of Fast Facts, fascinating snippets of information on the topic covered.

Browse through all of our Fast Facts indexed by topic