able to do over a hundred kilometres an hour.
A racehorse can gallop at sixty kilometres an hour,
and even an ostrich can do fifty kilometres an hour.
A fast runner can hit thirty-five kilometres an hour.
And while man is not as fast as many other animals,
he is capable of movements which are unique in the animal world.
And that's the topic for today's program, How We Move.
Most animals are able to move,
and the most important reason for this movement is survival.
A fish is able to swim to escape the jaws of a bigger fish.
And our cheetah has to run in order to get his meals.
Among the birds and the butterflies,
there are a number who are able to escape cold winters
simply by flying away from them.
There was a time when man moved to survive as well.
To a certain extent he still does.
But to see how and why man moves, let's begin at the beginning.
A baby starts moving inside the womb long before he's even born.
On entering the world, babies have very soft skeletons
and a very limited ability to move.
But as they grow older, they become stronger.
They're able to sit up and they learn to reach out and to grab hold of things.
And eventually most babies learn to crawl.
And finally the time comes to get up and walk.
It takes time to develop a sense of balance.
It takes time to get all the muscles to work together.
But it comes.
Eventually most people are able to move very well indeed.
For somebody with the skill and training,
moving can almost be a work of art.
But to understand how the body moves, we need to know how it's built.
The skeleton is the basic framework supporting the entire body,
protecting vital organs like the heart and lungs and making movement possible.
It is suspended from the all-important spine,
the long vertical bone in the middle of the neck and back.
It allows us to walk upright, leaving our hands and arms free to do other things.
Every one of the 206 bones in the skeleton is light, strong, and has its own special job.
The bones in the hands and arms are very flexible, enabling fine movement.
The legs and feet aren't nearly as delicate.
They need to be sturdy to support the body's weight.
The S-shaped curve of the spine cushions bumps and jolts when the body moves.
So we have flexible bones, sturdy bones, and a shock-absorbing spine.
At those places where the bones come together, we have joints.
At each joint, the bones are bound together by very strong fibres called ligaments.
Underneath the ligaments, the ends of the bone are padded with a layer of cartilage,
which helps to make the bulge at each end.
Inside the bulge, a fluid is produced, which oils the joint, making it easier to move.
Some joints don't move at all, like the ones in the skull.
Other joints move forwards and backwards, like a hinge.
The shoulder joint is able to move freely in many directions.
All this means that the skeleton allows the body to move, but it doesn't do the actual moving.
That takes muscles.
The muscles are joined to the bones by tendons.
Any movement of the muscle is thus passed on to the bone.
Muscles move the bones by contracting, that is, growing shorter and then relaxing.
They work in pairs, as we can see with this model.
The rubber bands here are like the muscles.
The forearm rises because the band on the right contracts.
Its partner on the other side grows longer.
The arm goes back down because the band on the left contracts, while the band on the right grows longer.
So the muscle at the top contracts to bring the arm up.
And the muscle at the bottom contracts to bring the arm down.
Some of the body's 600 or so muscles can be very powerful.
Others are much smaller and much more sensitive.
In fact, the tiny little face muscles give us a lot of expression.
Our muscles move because we have a brain and a nervous system.
The brain is able to send a message, sort of like a series of tiny electrical shocks to the muscles, telling them to contract.
The message from the brain travels along the spinal cord and then along a system of nerves which goes to all parts of the body.
When the brain decides it's time for some muscles to move, the message is sent in a split second.
There are some movements which take place without our even thinking about them.
Our hearts beat, our chests make us breathe.
It's virtually impossible for a person to hold their arm out and keep it perfectly still.
There's a rather special movement which doesn't involve the brain, and that's the reflex action.
Oh, wow!
In this case, a nerve sends two messages.
One heads for the brain, which the brain feels as pain.
The other travels directly to the spinal cord and then to the muscles near the pin.
They contract without the brain having told them anything.
However, most movements do involve the brain.
For instance, turning a steering wheel seems like a very simple thing to do.
But let's have a look at what happens in this situation.
The sound of the car horn is passed through the ear to the brain.
The brain decides it would be a good idea to keep the car in its proper lane.
It sends a message to the muscles which turn the steering wheel.
All this in only a fraction of a second.
You might have noticed that a lot of our movements are related to our senses.
We move because we feel something or because we hear something or see something.
As we develop, one of the things that we have to learn is to coordinate our movements with our vision.
To get the ball over the plate, you must be able to see the plate.
What's more, you must be able to concentrate.
Most of all, though, you must have practice so that your muscles can get the feel of what's needed to throw the ball where you want it.
And it doesn't matter if it's softball, cricket, tennis, squash, or what.
If you don't keep your eye on the ball, you're going to be in trouble.
Strike three, out.
The brain has to coordinate all kinds of movement.
The simple act of walking, for instance, can use over a hundred muscles which have to be organized into a smooth, continuous flow.
Imagine then the part the brain must play for an Olympic athlete
and the practice it must have taken to get such fantastic muscular coordination.
There are some things you wouldn't want to try at all until you had learned the right way to do them.
Almost all movement is controlled by a special part of the brain called the motor cortex, found about here.
It's interesting that the area at the top controls the legs, the arms, and the trunk, which make up the greatest part of the body.
The area in the middle is devoted to only one thing, the hand.
Cubans are the only animals who have so much brain controlling what seems to be such a small part of the body.
But this is what helps give us such a sensitive, multipurpose tool.
The rest of the motor cortex is devoted to the face and for a good reason.
Humans talk a lot. They use their tongues, their lips, their mouths, not just to make noises,
but to speak, to communicate in languages that are extremely complex.
In fact, it's really impossible to say just how important this movement is to people.
Our ability to move is a miracle in a way and something that is well worth taking care of.
If the bones are to stay in good shape, they need the right foods, such as the calcium found in milk.
Muscles need energy foods, like the natural sugar found in fruit and protein found in meat, cheese, and nuts.
If it's going to move well, a body must be held well.
This is particularly important for young people whose bones are still hardening into the shape that they will take as an adult.
And speaking of adults, here's a bit of a warning.
A lot of adults don't get the exercise they need.
In fact, they even look at people who are doing nothing more than walking,
as if they were some sort of strange creature.
People need to walk. They need to move.
We already know that lots of vigorous exercise is good for the heart, lungs, and blood circulation.
And it's good for the bones and the muscles too.
The harder they work, the stronger they become.
The more they move, the easier it becomes to move them.
And the easier it is, the more fun life can be.
Music
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