1. Level 2 Anatomy and Physiology
for Exercise
Muscles and Muscle Actions
2. Learning Outcomes
Session Aims:
• Identify the three types of muscle tissue and their
characteristics
• Describe the structure of skeletal muscle
• Identify how muscles attach to the skeleton
• Name and locate the main muscles
• Describe the structure and function of the pelvic
floor muscles
• Identify joint actions by specific muscle groups
3. Muscle Tissue Types
There are three types of muscle tissue:
• Voluntary
- Skeletal or striated muscle, involved in exercise
- Under conscious control
• Involuntary
- Smooth muscle, e.g. digestive tract, artery wall
-Under unconscious control
• Cardiac
- Striated and involuntary
- Specialist heart muscle
- Under unconscious control
5. Muscle Attachments
Muscles attach to the skeleton via:
• Tendons
Muscle fascia converges to form the tendon
which attaches to the bone
• Aponeurosis (flattened tendons) of other
muscles e.g. abdominals
• Directly onto the bone via muscle fascia
6. Muscle Contractions – General Rules
• Muscles pull
• A muscle crosses at least one joint
• A muscle contracts along its line of fibre
• Muscles work in pairs
7. Muscles
Muscles work in pairs:
Front & back
e.g. biceps & triceps
• Prime mover / agonist - the muscle responsible
for bringing about the action
e.g. biceps curl – agonist = bicep
• Antagonist - the opposite muscle that relaxes for
movement to occur
e.g. biceps curl – antagonist = tricep
8. Types of Muscle Contraction
• Concentric
Muscle develops tension and shortens,
overcoming load and gravity
• Eccentric
Muscle lengthens (with tension), resisting
gravity, returning a load to the starting
position in a controlled manner
• Isometric
Static or held
• Isotonic
Moving contraction (concentric and eccentric
phases)
9. Muscle Fibre Types
Skeletal muscles are made from several different
types of fibre and vary in two ways:
• Colour
• Speed of contraction
10. Muscle Fibre Types
Slow twitch fibres Fast twitch fibres
Type l Type llb Type lla
slow oxidative fibres fast glycolytic fibres fast oxidative glycolytic
red in colour white in colour pink in colour
contain large
numbers of
mitochondria
contain low numbers
of mitochondria
larger amount of
mitochondria than
type llb fibres
endurance type
activities
strength / anaerobic
type activities
intermediate fibres
assist type1 & typellb
11. Muscle Fibre Recruitment
The nervous system controls muscular contraction
Motor units consist of a single motor nerve and all
the muscle fibres it innervates
All of the fibres in that motor will be recruited when
the stimulus is sent from the nervous system – ‘all
or none law’
More units will be recruited when more strength is
required
13. Muscles of the Body
Level 2 Anatomy and Physiology
for Exercise
14. Anatomical Terms
Anatomical terms help you to
distinguish between different
parts of the anatomy, they also
help with learning muscle
names
The terms relate to the
anatomical position
15. Muscle Origins and Insertions
There are some general rules to help you to
understand muscle origins and insertions:
• Origin: usually nearer the midline of the body or
superior
• Insertion: usually away from the midline or
inferior
There are exceptions e.g. some muscles that run
vertically reverse this rule e.g. rectus abdominis
21. Deltoid
• Origin - clavicle and scapula
• Insertion - humerus
• Joint crossed - shoulder
• Joint action - abducts the arm,
assists in shoulder rotation &
flexion
e.g. Dumbell lateral raise
22. Latisimus Dorsi
• Origin -lumbar and sacral
vertebrae, thoracic vertebrae 7
12
• Insertion - humerus
• Joint crossed -shoulder
• Joint action - adducts, extends
and inwardly rotates the
shoulder
e.g. Lat pulldown
23. Pectoralis Major
• Origin - clavicle and sternum
• Insertion - humerus
• Joint crossed - shoulder
• Joint action - horizontal
flexion, adduction and inward
rotation of the arm
e.g. Press up, pec dec
24. Trapezius
• Origin - C7, all thoracic
vertebrae
• Insertion - clavicle and scapula
• Joint crossed - shoulder girdle
• 3 Joint actions:
- Upper fibres extend the neck
- Middle fibres retract the scapula
- Lower fibres depress the scapula
e.g. Shoulder shrugs
25. Rhomboids
• Origin - spinous processes of
cervical and thoracic vertebrae (C7
& T1–T5)
• Insertion - medial border of scapula
• Joint crossed - shoulder girdle
(moves scapula relative to rib cage)
• Joint actions - retracts scapula
downwardly rotates scapula
(works as a synergist with
pectoralis minor)
e.g. Pulling the shoulder blades
together
27. Transverse Abdominis
• Origin - iliac crest, lumbar fascia
and cartilage of interior six ribs
• Insertion - xiphoid process,
linea alba and pubis
• Joint crossed – lumbar vertebrae
• Joint action - compress the
abdomen, pulls the abdomen in
for posture and spine support
e.g. the plank
28. Rectus Abdominis
• Origin - pubis
• Insertion - ribs
• Joints crossed - lumbar and
thoracic vertebrae
• Joint action - flexes the
thoracic and lumbar spine
e.g. curl ups
29. Erector Spinae
• Origin - sacrum , ilium to
thorax
• Insertion - ribs, vertebrae, to
occipital bone (base of skull)
• Joints crossed - vertebrae
• Joint action - extends the
spine rotates the thoracic spine
e.g. dorsal raise, side twists
30. External Obliques
• Origin - lower ribs
• Insertion - ilium
• Joints crossed – the
vertebrae
• Joint action - laterally flexes
the thoracic spine
e.g. oblique curls
31. Internal Obliques
• Origin - ilium
• Insertion - lower ribs
• Joint crossed - vertebrae
• Joint action - laterally flexes
the thoracic spine, rotates
the thoracic spine
e.g. lying side bends
32. Muscles of the Lower Limb
Level 2 Anatomy and Physiology
for Exercise
33. Iliopsoas (Hip Flexors)
• Origin - all lumbar vertebrae and ilium
• Insertion - femur
• Joint crossed - hip
• Joint action - flexes the hip
e.g. kicks
34. Gluteals/Abductors
• Origin - ilium and sacrum
(Gluteus maximus only)
• Insertion - femur
• Joint crossed - hip
• Joint action - extends and
outwardly rotates the hip
(gluteus maximus), abducts and
inwardly rotates the hip (Gluteus
minimus and medius)
e.g. kick backs and squats
Gluteus Medius
35. Adductors
• Origin - pubis and
ischium
• Insertion - femur
• Joint crossed - hip
• Joint action - adducts
and outwardly rotates the hip
e.g. kicking across the body ad
stabilising the pelvis
36. Hamstrings
• Origin - ischium
• Insertion - tibia and fibula
• Joints crossed - hip and knee
• Joint action - knee flexion, hip
extension
e.g. hamstring curls
37. Quadriceps
• Origin - femur and Ilium
• Insertion - tibia (via patella tendon)
• Joints crossed - knee and hip
(rectus femoris is the only
quadricep to cross both hip and
knee joints)
• Joint action - all four muscles
extend the knee, the rectus
femoris also flexes the hip
e.g. leg extension
38. Gastrocnemius
• Origin - femur
• Insertion - calcaneus
• Joints crossed - ankle and
knee
• Joint action - ankle
plantarflexion, assists in knee
flexion
e.g. heel raises
41. Pelvic Floor Muscles
Situated under the pelvis
A double layered muscle consisting
of a deep and superficial layer of
muscle tissue and connective tissue
Provides stability for the pelvic
girdle
Controls organs and growing foetus
in pregnancy
Controls continence
42. Level 2 Anatomy and Physiology for
Exercise
Special Populations
The Muscular System
43. Special Populations
The Muscular System
Work on a case by case basis with individuals but bear
the following changes in mind
• Young people in the 14 – 16 age range
Muscle growth does not keep up with bone growth,
leading to clumsiness, motor skills are affected
• Pregnancy
The muscular system is affected by relaxin,
muscles are less pliable. This may have and affect
on balance and coordination
44. Special Populations
The Muscular System
• Ageing
Reduction in number of muscle fibre and fibre
size
Loss of contraction tissue
Reduction in motor units and neurons
Loss of power, strength and endurance
Changes in posture
Decreased motor skills, balance and coordination
Increased risk of falls
