A Healthy, Active Lifestyle &
Your Muscular System
• 1.2.4 a
• Understand the role of
the muscular system
during physical
activity and how
major muscle groups
benefit from particular
types of activity
• 1.2.4b
• Understand the role of
muscles in movement
What are the main jobs of the
muscular system?
• The muscular system is the driving force behind
movement, which happens as a result of muscles
contracting and lengthening. Muscles also define
body shape and maintain posture.
What are ‘voluntary muscles’?
• Voluntary muscles bring about movement.
These are the muscles which can be consciously
controlled, and can be trained to be stronger.
These are the muscles used when exercising and
playing sport
How do muscles create
movement?
• Muscles are attached
to the bones of the
skeleton by tendons.
Each muscle is made
up of muscle fibres
and when these
contract, or pull
against the skeleton,
movement takes place.
What is meant by the term
‘antagonistic pairs’?
• Muscles are arranged
in antagonistic pairs,
so when one muscle
contracts and pulls
the other one relaxes
to allow the joint to
work.
What are the 11 muscles important to the
GCSE examination?
•
•
•
•
•
Deltoid - shoulder muscles (abducts the upper arm
from body)
Trapezius - upper back muscle (rotates the shoulder
blades backwards)
Latissimus dorsi - lower back muscle (rotates upper
arm at the shoulders)
Pectorals - front of chest muscles (adduction of the
arm)
Abdominals - stomach muscles (flexion and
rotation of the trunk)
•
•
•
•
•
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Biceps - top of arm muscles (flexion of arm
at the elbow)
Triceps - underneath of arm muscles
(extension of arm at the elbow)
Gluteals - bum muscles (extension of the
upper leg)
Quadriceps - front of leg muscles (extension
of the leg at the knee)
Hamstrings - back of leg muscles (flexion of
the leg at the knee)
Gastrocnemius - calf muscles (plantarflexion of the foot)
What are ‘isometric
contractions’?
• Isometric
contractions are
muscle contractions
which result in
increased tension but
the length of the
muscle stays the
same, for example
when pushing against
a wall.
•
What are ‘isotonic
contractions’?
• Isotonic contractions
are muscle
contractions which
result in limb
movement.
What are the long-term benefits of the
muscular system resulting from
regular exercise?
•
1.Muscle hypertrophy - when
using the principle progressive
overload, the muscle’s fibres
become torn causing trauma. The
muscle will rebuild itself, making it
slightly stronger. This increase in
muscle mass is muscle
hypertrophy.
•
•
2.Increase in muscular strength muscle hypertrophy will lead to
increased muscular strength. This
can also lead to an increase in
power (strength x speed
3. Increase in muscular
endurance - as with muscular
strength, muscles will be able to
withstand more and more and they
are progressively overloaded,
therefore muscular endurance will
increase.
What potential injuries are
there to the muscular system?
• Soft tissue injuries to muscles
- these include tears, pulls, and
strains. These occur when small
muscles fibres are torn from
their attachment to the tendon.
During exercise, muscle fibres
have to contract and relax very
quickly, this can cause
connective tissue and blood
vessels inside them to be torn.
• Muscle atrophy When strength training
is stopped, a loss of
muscle mass and
strength can occur,
this is called muscle
atrophy.
What is meant by the acronym
‘RICE’?
• Rest - a period of time to allow the injury to recover.
• Ice - this directs cold to the injured tissue and can relief pain and limit
swelling.
• Compression - helps limit and reduce swelling of the injury.
• Elevation - reduces swelling by elevating injured part of body above the
level of the heart.
The Muscular System
These are the major muscles of the body…
Deltoids
Pectorals
Biceps
Trapezius
Triceps
Latissimus Dorsi
Abdominals
Gluteals
Quadriceps
Hamstrings
Gastrocnemius
Skip to
labelled
diagram
Front View
Back View
Functions of the Body Muscles
Muscle
Gluteus
maximus
Hamstrings
A sporting example
Action produced
running
Extends the
upper leg.
sprinting
.
Flexes the legs at
the knees.
Gastrocnemius Running – pushing
onto toes.
Plantar flexes the
foot.
Muscle
Position in the
Body
Main Action
Trapezius
Rowing .
Hold and rotates
the shoulder
blades backwards
Latissimus
Dorsi
Swimming
butterfly.
Rotates upper
arm at the
shoulders.
Straightening the
arm to throw a
cricket ball.
Extends arm at
elbow.
Triceps
Muscle
Position in the
Body
Main Action
Deltoids
Serving in
tennis when arm
goes above the
head.
Abducts (takes
away ) the upper
arm from the
body.
Biceps
Bending the
arm to throw a
cricket ball.
Flexes the arms
at the elbows.
Kicking a
football.
Extends the legs
at the knees.
Quadriceps
Muscle
Pectorals
Abdominals
Position in the
body
Main Action
Swimming front
crawl.
Adducts the arm.
Rowing .
Flexes and rotates
the trunk.
1. Cardiac Muscle

The cardiac muscle works without you
thinking about it - there is no
Coronary
conscious control.
Artery

Even when asleep it is capable of constant,
automatic and rhythmical contractions.

It is only found in the walls of the heart, which has it’s own
blood supply provided by the coronary artery.

When it contracts, the heart pumps blood to the lungs and around
the rest of the body.
Question: What happens when the coronary arteries become blocked?
Answer: The person will suffer a heart attack, as the cardiac muscle
of the heart needs a constant supply of oxygen to keep contracting
(beating). If immediate medical attention is not given the person will die.
2. Involuntary Muscle

Involuntary muscle works without you thinking about it - there is
no conscious control.

Also know as smooth muscle.

Found in the walls of arteries, veins, stomach and intestine.
Artery
Vein
Small
Intestine
3. Voluntary Muscle

You have full conscious control over voluntary muscles.
However they can also be involved in involuntary reflexes.

They are also know as striated or skeletal muscle.

They are attached to bone and cause the skeleton to move.

Examples include the triceps and hamstrings.

They are the largest group of muscles in the body.
Antagonistic Muscles

Skeletal muscles work across a joint and are attached to the
bones by strong cords known as tendons.

They work in pairs, each contracting or relaxing in turn to create
movement.
Movement of the arm
at the elbow
Flexion (Bending) of the Arm

The muscle doing the work (contracting) and creating the
movement is called the agonist or prime mover.

The muscle which is relaxing and letting the movement take place
is called the antagonist.
Agonist or Prime Mover
(Biceps contract)

Antagonist
(Triceps relax)
Other muscles support the prime mover (agonist) in creating
movement and these are called synergists.
The Origin and Insertion

When a muscle contracts, only one bone moves leaving the other
stationary. The points at which the tendons are attached to the
bone are known as the origin and the insertion.

The origin is where the tendon of the muscle joins the stationary
bone(s).

The insertion is where the tendon of the muscle joins the moving
bone(s).
Origin
The arm is being flexed.
The radius and ulna are the moving bones.
The humerus and scapular are stationary bones.
Insertion
Extension (Straightening) of the Arm
Locate and name the following parts involved in the extension of the arm:



Agonist (prime mover)
Origin
Any Bones
Scapula


Antagonist
Insertion
Origin
Triceps: agonist
(prime mover)
contracting muscle
Biceps: antagonist
relaxing muscle
Carpals
Radius
Humerus
Insertion
Phalanges
Metacarpals
Ulna
What Makes a Muscle Contract?
We have conscious control over all our skeletal muscles and as a
result, these muscles will only contract when told to do so by the
Central Nervous System (CNS).
Types of Muscle Contraction
When a muscle contracts, it does so in 2 main ways…
Isometric Contraction or Isotonic Contraction.
1. Isometric Contraction

The muscle stays the same length as it works.

As a result there is no movement.

The muscles in the back are a good example - the trapezius
works in this way when maintaining our posture.

The hand push is another good example of isometric contraction.
Force
Force
There is no movement!
2. Isotonic Contraction

The muscle changes length as it works; either lengthening or
shortening.

Shortening is called a concentric contraction.

Lengthening is called an eccentric contraction.

The hamstrings and quadriceps in the legs work in this way when
performing squats.


The 'biceps curl' is a good example of isotonic contraction.
Isotonic = WITH MOVEMENT
The muscle contraction causes movement of the bones
and the body can be seen to physically move
To remember:
-Tonic water is fizzy the bubbles move
Immediate Effects of Exercise
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The Effects of Regular Training on the
muscular system
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Muscles and Injury
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Lifestyle , performance-enhancing drugs and the
muscular system
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