Download How muscles work

AgesKnowledge
11–14 Card
Ages 14–16
In Experiment A you will investigate the relationship between
muscle size and the number of repetitions of various upper body
exercises that you can do. Experiment D focuses on the effects of
fatigue from exercise and whether fatigue is localised.
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How important are
muscles for sporting
success?
How muscles work
Muscles are attached to our bones by tendons. When muscles contract
they get shorter. When they do so they pull the bone they are
attached to which acts as a lever to create movement.
© Bertrand Guay/AFP/
Getty Images
© Patrik
Giardino/
Stone/Getty
Images
Is a sprinter born rather than made? We know that muscle
size and muscle type are very important for sporting
performance. The size and type of a muscle will determine
the amount of force that it can generate and for how long it can
contract before fatigue sets in.
Muscles work in ‘antagonistic muscle pairs’. This means that
one muscle pulls the bone to one position, such as the biceps
flexing the elbow to pull the forearm up. Then the other
muscle pulls on the bone to return it to the original position,
in this case the triceps extend the elbow
tendon tocontracted
straighten the arm.
biceps
tendon
The
strength of
your muscles
will affect
how well you
perform.
© Bob Thomas Sports
Photography/Getty Images
© Chris Hyde/
Getty Images
tendon
relaxed
triceps
Bent arm (contracted).
relaxed
biceps
contracted
triceps
tendon
contracted
triceps
Straight arm
(relaxed).
Muscles
work in
antagonistic
pairs.
Muscle fibre types are roughly split into two categories;
fast-twitch and slow-twitch. Fast-twitch muscle fibres
produce fast movements over short periods of time so
are ideal for events such as sprinting. Slow-twitch muscle
fibres produce slower contractions but can continue
to contract over long periods of time so are ideal for
endurance events, such as long–distance cycling or
running.
When our team of sport scientists are able to use
their understanding of the human body and how it
responds to exercise we can really help athletes go
faster, be stronger, go higher, and so push forward the
boundaries of human achievements. And that is what
makes my work so exciting.
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a.Which sorts
ell in if you had
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think you co
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large upper bo
te
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b
Straight arm
(relaxed).
Bent arm (contracted).
My name is Steve Ingham and I am the Head of
Physiology for the English Institute of Sport. I work with
our very best athletes who are training in the hope of
winning Olympic medals.
www.getinthezone.org.uk
relaxed
triceps
contracted
biceps
tendon
Tests on retired sprinters have shown that they have
very high percentages of fast-twitch muscle fibres. The
proportion of the different muscle fibres is determined
by removing and analysing a very small section of their
muscle fibre, called a muscle biopsy. Most sprinters
who are still competing won’t agree to undergo muscle
biopsies. So, at the moment, we can only estimate what
percentage of fast-twitch muscle fibres are in Usain Bolt’s
legs!
In Experiment B you will investigate the relationship
between upper and lower body strength whilst Experiment
C focuses the investigation on whether people who are
good at power sports are also good at endurance sports.
Ages 14–16
My name is Odette Hughes and I am Associate Director of
Wayne McGregor | Random Dance. I am responsible for
the everyday artistic supervision of McGregor’s Company,
overseeing all performances, and directing all rehearsals.
Getting
‘in the zone’
For muscle endurance training, wherever possible I
would lead a circuit lap, which is purely for stamina and
endurance. It normally consists of 20–25 minutes of fastpaced exercises.
The lap would have ten exercise posts. Each dancer would
have 1 minute on each post. The exercises at each post
would consist of squats, planks, press-ups, star jumps or
skipping. After a minute on a post, we would run two laps
around the studio clockwise stopping at the next post to the
left. This would continue until the dancers have completed all
posts. The session would finish with sprinting for a further five
laps.
© Ravi Deepres/Wayne
McGregor | Random
Dance
The experiments you will be carrying out are also used on a regular
basis as a conditioning tool for athletes. Press-ups, triceps dips,
and pull-ups are good for conditioning the trunk and arms. Vertical
jumps are good for conditioning the legs. They are also used regularly
in jumping sports like basketball and volleyball to assess the
improvement of an athlete in his or her jumping abilities.
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whether you
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b.How could
ndurance spo
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good a
c.How could
you investiga
te whether fa
in one set of
tigue
muscles will
affect the
performance
of another se
t of muscles?
© Phil Walter /
Getty Images
I’m Simon Drane, I’m a sports psychologist and spend the majority
of my time at the National Badminton Centre working with the GB
Olympic Badminton squad. My main role is to help athletes get
stronger mentally so that they can perform at their best when the
pressure is on.
The Olympic athletes that I work with spend a lot of time in the gym
training the muscles that are important for their sport. It is vital
that the exercises that they perform are completed with focus and
concentration because the wrong technique could either not work
the important muscles or even result in an injury.
Before doing a specific exercise physically, I encourage them to
rehearse it mentally, by imagining it in their head. They picture
themselves doing the exercise, using all their senses including
vision, hearing, and also feeling. They try to imagine which muscles
will be moving to complete the exercise and this helps get them
ready for when they do the exercise physically. Try it for yourself.
Hi, my name is Ian Gatt. I’m a sports physiotherapist and I work as the lead
for the GB Boxing programme. My role involves working with boxers, both
male and female, to monitor their health and fitness status predominantly
through injury management.
In physiotherapy we use these experiments as part of exercise
rehabilitation to improve the strength of an injured area. Depending on
which joint or muscle is involved we would select the appropriate exercise.
© Nathan Denette/The Canadian
Press/Press Association Images
Training muscles
Resistance
training
is done to
encourage muscle
tissue to grow and
get stronger.
For all types of muscle tissue to grow and get
stronger, they need to be used in strength training
exercises. These are exercises where the muscles
work to move some form of resistance, for example,
lifting dumbbells 1.
© DNF-Style Photography/shutterstock.com
My name is Andy Shaw and I am a personal trainer to both elite and recreational athletes. I
have worked with the English Rugby Football Union (RFU) and individual rugby players. More
recently I have trained triathletes and distance runners for major events.
Unless there is a specific injury, most resistance training is done using free weights and
designed to replicate the movement pattern required. As a strength trainer it is necessary to look
at the whole picture. It is not just bigger individual muscles that make the difference but the ability
to recruit more muscles in the body, for example, a boxer’s strength initiates from the legs not the
arms.
© Andy Shaw
It is important to gradually increase frequency and intensity so as not to place undue stress on
the athlete and therefore limit the risk of injury.
www.getinthezone.org.uk
1
. Baar, Training for endurance and strength: lessons from cell signalling,
K
Medicine and Science in Sports and Exercise, 2006, 38(11), pp 1939–44.