1. +
MUSCULAR SYSTEM
Skeletal Muscles and their classifications

2. +
KEY CONCEPTS

Skeletal muscles all have features that distinguish what
they can do; in particular, movements that they make and
force they can generate.

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KEY FUNCTIONS

Support and posture – muscles are in a continuous state of
‘tone’ that affects their ability to help our body maintain an
upright posture.
Poor posture can result in aches and pains
The trapezius, rhomboids and latissimus dorsi are crucial
postural muscles

Movement – voluntary control

Essential body functions – generally under involuntary
control (which have little or no conscious control)



Digestion
Respiration
Circulation

4. +
Common features of muscles

Nervous control – CNS stimulus controls muscle action

Contractility – when muscles contract they get shorter

Extensibility – muscles have the capacity to lengthen

Elasticity – muscles return to the original shape/size after
stretching

Atrophy – muscles can decrease in size as a result of injury
or lack of exercise

Hypertrophy – muscle can increase in size (grow) with
increased exercise/training

5. +
MUSCLE FIBER TYPES

Cardiac


Smooth


Muscles of the heart
Digestive system and
blood vessels
Skeletal

Attached to bones and
responsible for
movement

6. +
SKELETAL MUSCLES
YOU NEED TO KNOW!

8. +
CLASSIFICATION OF
SKELETAL MUSCLE

9. +
OVERVIEW

Skeletal Muscles can be classified by their fibre
arrangement around the tendon.

10. +
FUSIFORM MUSCLES

the muscle fibres run the
length of the muscle belly.

Designed for mobility – low
force over a long range

E.g. Sartorius, biceps

11. +
PENNIFORM MUSCLES

Fibres run at angles to the tendon. Designed for strength
and power.

They make up 75 per cent of the skeletal muscles

Three Categories

Unipennate

Bipennate

Multipennate

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UNIPENNATE

Fibres are found on only
one side of a central tendon

E.g. Tibialis Anterior

13. +
BIPENNATE
MUSCLES

The fibres run off either side
of a central tendon

E.g. rectus femoris (quads)

14. +
MULTIPENNATE
MUSCLES

Fibres branch out from
several tendons.

This arrangement enables the
body the generate the greatest
force.

E.g. Deltoid

15. +
Radiate Muscles

These muscles are a
compromise between fusiform
and pennate muscles because
they are capable of producing
strength and power without
compromising mobility

Eg: pectoralis major, latissimus
dorsi