Topic 9
The Muscular System
Learning Objectives
To learn about the muscular system
Success Criteria
F-G
I can list the muscles and types of movement
D-E
I can identify different types of movement
and muscles from sporting pictures
B-C
I can answer multiple choice and short
answer describe questions
A*-A I can answer long response explaining
questions
The Muscles
Front of Body
Biceps
Pectorals
Abdominals
Quadriceps
The Muscles
Back of Body
Deltoid
Trapezius
Triceps
Lattisimus
Dorsi
Gluteus
maximus
Hamstrings
Gastrocnemius
Antagonistic Muscle Pairs
There are 2 groups of muscles that are arranged in
antagonistic muscle pairs
1. The Biceps & Triceps
As 1 muscle contracts, the
other one relaxes
When the biceps contract, the
triceps are relaxing!
When the triceps contract,
the Biceps are relaxing!
Antagonistic Muscle Pairs
There are 2 groups of muscles that are arranged in
antagonistic muscle pairs
2. Hamstrings & Quadriceps
As 1 muscle contracts, the
other one relaxes
When the quadriceps contract,
the hamstrings are relaxing!
When the hamstrings contract,
the quadriceps are relaxing!
Muscle Movement
There are 5 different types of muscle movement
that you must know about
1. Flexion
There are 5 different types of muscle movement
that you must know about
• Flexion is when joints
bend
• This example shows
flexion of the arm at the
elbow
• Flexion of the arm
happens when the
biceps contract
1. Flexion
There are 5 different types of muscle movement
that you must know about
• Flexion is when joints
bend
• This example shows
flexion of the leg at the
knee
• Flexion of the leg occurs
when the hamstrings
contract
2. Extension
There are 5 different types of muscle movement
that you must know about
• Extension is when joints
straighten
• This example shows
extension of the arm at
the elbow joint
• The triceps are
responsible for arm
extension
2. Extension
There are 5 different types of muscle movement
that you must know about
• Extension is when joints
straighten
• This example shows
extension of the leg at
the knee joint
• The quadriceps cause
leg extension
3. Rotation
There are 5 different types of muscle movement
that you must know about
• Rotation causes
movement in a circular
motion
• This example shows
rotation at the upper arm
around the shoulders
• Happens when Lattisimus
dorsi contracts
3. Rotation
There are 5 different types of muscle movement
that you must know about
• Rotation causes
movement in a circular
motion
• This example shows
rotation of the body trunk
• Body rotation is caused
by the abdominals
contracting
4. Abduction
There are 5 different types of muscle movement
that you must know about
Abduction causes arms and
legs to move away from the
body
This example shows
abduction of the arm caused
when the deltoid muscle
contracts
5. Adduction
There are 5 different types of muscle movement
that you must know about
• Adduction causes arms
and legs to move
towards from the body
• This example shows
adduction of the arm
caused the pectoral
muscles contracting
Muscle Contractions
There are 2 different types of muscle contraction
that you must know about
1. Isotonic Contractions
Isotonic contractions are
where 1 muscle contracts (&
shortens) while another
muscle relaxes (& lengthens)
95% of the contractions you
make in sport are Isotonic
Muscle Contractions
There are 2 different types of muscle contraction
that you must know about
2. Isometric Contractions
Isometric contractions
happen when the muscles
contract but remain in a fixed
position
There is no change in the
length of the muscle
Short Term Effects
There is only 1 immediate effect on the muscles
1. Lactic Acid
When you exercise
Anaerobically (without
oxygen) your muscles
produce a poison called
lactic acid
Lactic acid causes the
muscles to feel like they are
on fire
Long Term Effects
There is only 1 long term effect on the muscles
1. Hypertrophy
Hypertrophy is when muscles
grow and get larger
Strength training is the main
stimulus that causes muscle
hypertrophy
The opposite of this when
muscles shrink is called atrophy