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Skeletal
Most common
 Attached to bone (via tendons)
 Voluntary
 Striated
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Cardiac Muscle
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In the heart only
Involuntary
Striated
Smooth Muscle
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Surrounds organs
Slow, long contractions
Involuntary
Non-striated; forms dense sheets
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Complex linking of the muscular and
neurological systems
Constant use and practice improves the
quality, efficiency and ability of these systems
to work together

E.g. agility training
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
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Nerves transmit impulses in waves- the resulting contraction is
called a muscle twitch
1 nerve + the muscle fibers it innervates = motor unit
1 nerve stimulates many muscle fibers, thereby producing muscle
movements.
 1 nerve + a few muscle fibers =fine movements (eg blinking)
 1 nerve + lots of fibers = gross/big movements (eg contraction
of the quadriceps)
All-or-None Principle
 When a motor unit is stimulated to contract, either ALL of the
muscle fibers will contract, or none will

Concentric
Muscle fibers shorten
 E.g. bicep flexion


Eccentric
Muscle fibers lengthen
 Eg bicep extension

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Isometric
Contraction without change in length of muscle; no
motion; decreased risk of injury
 E.g. pushing against a wall; doing a abdominal plank.


http://www.youtube.com/watch?v=A1haS8h
R1lE
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Origin

where the muscle attaches to more stationary of the
bones of skeleton.
 Usually more superior

Insertion
Where the muscle attaches to the bone that moves
most
 Usually more inferior

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
Skeletal muscles are arranged as opposing
pairs
Agonist
Prime mover of the body part
 Eg. During knee extension, quadriceps are the
agonist


Antagonist


Counter-acts the agonist
Eg. During knee extension, hamstrings are the
antagonist
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Flexor hallicus longus
Anterior tibialis
Soleus
Gastrocnemius
Patella
Quadriceps
Hamstrings
Gluteus medius, minimus, maximus
Abductor muscles
Adductor muscles
Peroneals
Can you label these muscles??


Leg- refers to lower limb below the knee
Thigh = hip to knee
Muscle/Musc
le Group
Origin
Insertion
Action
Toe/foot
extensors
Anterior
tibia/fibula
Distal phalanges
(toes)
Extend the toes
Tibialis
Anterior
Ant. Tibia
Top of foot
Dorsiflexion of ankle; foot
inversion
Gastrocnemi
us
Lateral and
medial heads
both originate on
femur
Achilles tendon,
which inserts on the
heel (calcaneus)
Plantar flexes ankle; flexes
knee
Soleus
Upper fibula
Tendon combines
with gastroc to form
achilles heel.
Plantar flexes ankle
Flexor
hallicus
longus
Posterior fibula
End of big toe (ie the
distal aspect)
Flexes big toe
Peroneals
Fibula
1st and 5th metatarsals
Plantar flexion; eversion
Muscle/
Muscle Group
Origin
Insertion
Action
Quadriceps
femoris
Iliac spine
(pelvis) &
proximal femur
Come together
as patellar
tendon, insert
on tibia
Knee extension
and hip flexion
Hamstrings
Pelvis
Head of fibula
and tibia
Hip extension;
knee flexion;
internal knee
rotation
Gluteus
maximus
Pelvis and
lower spine
(iliac crest,
sacrum, coccyx)
Proximal femur
(greater
trochanter) and
iliotibial tract (
IT band)
Hip extension,
external
rotation
Gluteus medius
& minimus
Lateral pelvis
Greater
trochanter/
femur
Abduction;
internal hip
rotation
Hip adductors
Distal pelvis
Along the
femur
Hip/ thigh
adduction
Location
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Groups:


Figure out where each muscle is located- ie anterior, posterior, medial,
lateral
Questions:

While out trail running, Marie steps on a root and experiences an eversion
of her ankle.
 a) What is this injury? (what happens to the sole of the foot)
 b) Which muscles will be injured?
 c) Which muscles would have contracted to aid ankle eversion?

Many athletes, especially women, have muscular imbalances between their
quadriceps and hamstring muscle groups(quads are often stronger).
 a) Why are these athletes at a higher risk for injury?
 b) What joint is most likely to be injured?
 c) What type of injury might result at this joint?

The gluteus maximus is one of the strongest muscles in the body.
 a) What would happen to hip/thigh rotation if other muscles do not compensate
for this strength?
 b) Which muscles are the antagonists to hip extension by the glutius maximus?
Muscle/Group
Origin
Insertion
Action
Rectus Abdominus
Pubic crest
Xyphoid process
and inferior ribs
Flex trunk;
expiration; “bearing
down”
External Obliques
AND
Transverse abdominis
Lower 8 ribs
Pelvis
Flex and rotate
vertebrae; compress
abdomen during
expiration
Quadratus Lumborum
Pelvis and lumbar
vert.
Lower rib and
upper lumbar
vert.
Extends and bends
vert. column; helps
with breathing
Diaphragm
Sternum, ribs,
lumbar vert.
Central tendon
Respiration;
anatomical border,
separating thoracic
and abdominal
cavities
Intercostals
Inferior of each rib
Superior of each
rib
respiration
Location
Erector Spinae
Layers of muscle
b/w each rib

Jeff sustained a serious injury to the left side of
his trunk.




What muscle group(s) are affected?
What movements will be compromised?
What could happen if the diaphragm was
punctured or torn in half?
A pregnant woman is in a car accident and
sustains an injury to her rectus abdominus
(baby is fine).

What might be the consequences?
Muscle/group Origin
Insertion
Action
Latissimus
dorsi
Sacrum,
lumbar,
thoracic vert
Humerus
Adduction,
extension,
interior rotation
of arm
Pectoralis major
Clavicle,
sternum,
external
obliques
Humerus
Adduction,
flexion, internal
rotation of arm
Rotator Cuff (4
muscles)
Scapula
Humerus
Shoulder
stabilization
and rotation
Trapezius
Base of occipital
bone (head);
cervical and
thoracic vert.
Scapula and
shoulder bone
bones
(acromion,
clavicle)
Moves the
scapula;
extends the
neck
Deltoids
(anterior,
lateral,
posterior)
Clavicle,
acromion,
scapula
Humerus
Flexion,
extension,
abduction and
rotation of arm
Location
Muscle/Grou
p
Origin
Insertion
Action
Biceps
brachiii
2 places on
the scapula
Radius
Elbow flexion;
forearm
supination
Triceps
brachii
3 heads on
posterior
humerus
Ulna
(olecranonpoint of
elbow)
Elbow
extension
Hand Flexors
Elbow area
Hand/fingers
Flex wrist,
hand, fingers
Hand
Extensors
Elbow area
Hand/fingers
Extend wrist,
hand, fingers
Location

Types:



Fibrous joints – no movement- eg sutures of the skull
Cartilaginous joints- some movement- eg between
the vertebrae
Synovial joints- lots of movement







6 common types:
Ball and socket (eg the hip, shoulder)
Gliding (eg foot)
Hinge (elbow, knee)
Pivot (neck)
Saddle (thumb)
Ellipsoid (wrist)


Separated by a lubricating fluid and cartilage
Joined by ligaments that also help form the
joint capsule (surrounds and protects joint)

http://www.youtube.com/watch?v=9QTCBrefXso

Tendinitis



Tears, Sprains, Pulls




Inflammation of a tendon via irritation due to
overuse/abnormal use
Tx- rest, cold, heat therapy, anti-inflammatories
Tear/pull= injury to muscle
Sprain = injury to ligaments and tendons
3 levels of severity: 1st degree injury is mild; 2nd is moderate; 3rd
is severe
Dislocations


When bone displaced from original position
Symptoms:
 Joint looks awkward/deformed
 Painful to touch/move
 Inability to use joint

Recognizing an Injury

SHARP





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Swelling
Heat
Altered function
Red
Pain
Treating

RICE





Rest
Ice
Compression
Elevation
NEVER use heat to initially treat an injury
 Why?





strengthen surrounding muscles
Stretch muscles
Proper conditioning
Warm up before exercising
Proprioceptive training

Muscles Causing Movement at the Hip Joint
 Iliopsoas Adductor Muscles
 Gluteus Maximus
 Gluteus Medius

Muscles Causing Movement at the Knee Joint
 Sartorius
 Quadriceps Group
 Rectus Femoris
 Vastus Muscles
 Hamstring Group
 Biceps Femoris
 Semimembranosus
 Semitendinosus Muscles Causing Movement at the Ankle
and Foot
 Tibialis Anterior
 Peroneus Muscles
 Gastrocnemius