Muscle Pathophysiology and Treatment

Question 1

how does age influence muscle performance?

Answer 1

as you age, the CSA of type 2 fibers decreases

Question 2

what are the 3 factors that influence muscle performance?

Answer 2

age, temperature, and immobilization/disuse

Question 3

how does temperature affect muscle performance?

Answer 3

as temperature increases, so does elasticity

Question 4

how does immobilization/disuse influence muscles performance?

Answer 4

if a muscle is immobilized in a shortened position, it will be injured with less force/stretch (the opposite is true of lengthened)

Question 5

what is muscle tone?

Answer 5

the resistance to stretch in resting muscle

Question 6

what contributes to normal resting tone?

Answer 6

titan and weak actin-myosin bonds

Question 7

what is the role of weak actin-myosin bonds in muscle tone?

Answer 7

they provide resistance to stretch post prolonged contraction

Question 8

what are some different muscles injuries?

Answer 8

excessive strain

contusions

excessive tension

lacerations

thermal stress

myotoxic agents

some local anesthetic agents

excessive use of corticosteroids

snake and bee venom

Question 9

what 2 muscles injuries make up 90% of muscles injuries?

Answer 9

excessive strain and contusions

Question 10

what is contusion?

Answer 10

heavy compressive forces or direct blow causes a hematoma to develop intramuscularly or intermuscularly

Question 11

what is an intramuscular contusion hematoma?

Answer 11

the size of the muscle is limited by the fascia

Question 12

what can intramuscular contusion hematoma lead to?

Answer 12

compartment syndrome

Question 13

what is intramuscular contusion hematoma associated with?

Answer 13

muscles strain and bruising

Question 14

which contusion hematoma is associated with more pain and loss of function?

Answer 14

intramuscular

Question 15

what is intermuscular contusion hematoma?

Answer 15

ruptured muscles fascia causes blood to leak into interfacial and interstitial spaces causing less severe pain

Question 16

what is a strain?

Answer 16

excessive pulling force on a muscle causing overstretching

Question 17

what are the contributors to strain?

Answer 17

inadequate flexibility, strength, endurance, or rehab of previous injury

dyssynergistic muscle contraction

insufficient warm up

inadequate warm up

Question 18

what are the 2 classifications of muscle injuries?

Answer 18

exercise-induced muscles injury (DOMS)

contusions

Question 19

what causes exercise induced muscle injury?

Answer 19

increased activity

unaccustomed activity

excessive eccentric work

viral infection

secondary to muscles cell damage

Question 20

what is a first degree (mild) strain?

Answer 20

minimal structural damage

minimal hemorrhage

early resolution

Question 21

what is a 2nd degree (moderate) strain?

Answer 21

partial tear

large spectrum of injury

significant early functional loss

Question 22

what is a 3rd degree (severe) strain?

Answer 22

complete tear

may require aspiration

Question 23

what is aspiration?

Answer 23

using a needle to draw fluid out of a muscle

Question 24

what does yellow/clear fluid indicate in aspiration?

Answer 24

joint fluid

Question 25

what does red fluid indicate in aspiration?

Answer 25

blood

Question 26

what does serosanguinous fluid in aspiration looks like and mean?

Answer 26

pinkish red fluid that indicates some level of bleeding

Question 27

what muscles are most at risk for strain?

Answer 27

long fusiform muscles that cross 2 joints muscles with propensity for eccentric contraction (hamstrings, quads, medial gastrocs, biceps brachii)

Question 28

what is a common site for muscle strain?

Answer 28

at the musculotendinous junction

Question 29

why is the musculotendinous junction a common site for muscle strain?

Answer 29

bc this is an area where compliant muscles fibers become noncompliant tendon

Question 30

what are factors that could induce strain?

Answer 30

sudden overstretch sudden contraction decelerating limb insufficient warm-up lack of flexibility steroid use previous muscle injury collagen disease

Question 31

does muscle have regenerative capacity?

Answer 31

yes, muscles have a significant regenerative capacity bc muscle tissue can replace itself with muscle tissue

Question 32

t/f: muscle has a similar healing process regardless of cause of injury

Answer 32

true!

Question 33

the outcomes and time of healing of muscles depend on what 3 things?

Answer 33

type of injury, severity, and extent of injury

Question 34

does pathology of muscle injury depend on the cause of injury?

Answer 34

yes

Question 35

what is a potential consequence of muscle injury?

Answer 35

atrophy

Question 36

what type of muscles have an increased potential for atrophy than antagonists?

Answer 36

antigravity muscles (ie. quads)

Question 37

t/f: stronger, more flexible muscle heals faster and is less prone to injury

Answer 37

true!

Question 38

what are the 3 phases of muscle healing?

Answer 38

1. destruction phase 2. repair phase 3. remodeling phase

Question 39

what is the destruction phase of muscle healing?

Answer 39

extensive proliferation of satellite cells that become myoblasts in the first few days post injury cells maintain mitotic abilities and go through the cell cycle

Question 40

what is the destruction phase of muscle healing characterized by?

Answer 40

necrosis, degeneration, and hematoma and edema

Question 41

what is the repair phase of muscle healing?

Answer 41

hematoma formation fills the gaps b/w ruptured fibers coagulation releases anaphylatoxins that activate sentinel cells triggering the inflammatory response and satellite cells to proliferate to reconstruct the injured site

Question 42

what happens in the first day under the repair phase of muscle healing?

Answer 42

invasion of inflammatory cells including phagocytes

Question 43

what happens in the 1st week of healing under the repair phase of muscle healing?

Answer 43

the injury is at it's weakest point of the musculotendonous unit

Question 44

what happens in the 1st few weeks of healing under the repair phase of muscle healing?

Answer 44

myofibers grow and mature

Question 45

what happens in the final stage of the regenerative process?

Answer 45

integration of neural elements and formation of a functional neuromuscular junction

Question 46

it is expected that there will be a return to function provided that there is...

Answer 46

continuity of the muscles fiber and innervation, vascular supply, and an intact ECM

Question 47

what is the remodeling phase of muscle healing?

Answer 47

regenerated muscle matures and contracts with reorganization of the scar tissue restoration of normal capacity and increased tensile strength over time restoring the type 1 to type 3 collagen proportions

Question 48

why do we need proper controlled mobility post acute phase?

Answer 48

it allows for scar formation, muscles regeneration, better fiber orientation, and normalization of tensile properties of muscles

Question 49

t/f: prevention is easier than treatment of muscles injuries

Answer 49

true!

Question 50

what are the treatments of muscle injuries?

Answer 50

prevention patient education controlled mobility meds and modalities ROM

Question 51

what is the role of patient education in healing?

Answer 51

managing patient expectations

Question 52

what is the typical progression of muscles injury PT?

Answer 52

PROM-->AAROM--> submaximal isometrics--> more maximal isometrics--> PREs isotonic

Question 53

what are the effects of long term muscle immobility?

Answer 53

prolonged shortening: lose sarcomeres prolonged lengthening: gain sarcomeres

Question 54

what are the effects of short term immobility?

Answer 54

increased resistance to passive stretch through weak actin-myosin bonds

Question 55

with a slow stretch, cross bridges have ____ time to detach

Answer 55

more

Question 56

with a fast stretch, cross bridges have ____ time to detach

Answer 56

no

Question 57

what is an example of a fast stretch consequence?

Answer 57

stretch reflex

Question 58

what is muscle fatigue?

Answer 58

diminished response to repeated stimuli due to progressive deteriment of motor unit potentials leading to gradual decline in force production

Question 59

what factors is muscle fatigue related to that may cause it?

Answer 59

decreased energy stores, oxygen, sensitivity, and availability of intracellular Ca2+ build up of H+

Question 60

what are the signs of muscle fatigue?

Answer 60

discomfort (pain and cramping) shaking/trembling contraction contractions slow with reps jerky, inconsistent movements movement substitution inability to continue low-intensity activity inability to complete movement decline in peak torque w/isokinetics

Question 61

what are the signs of form fatigue?

Answer 61

jerky, inconsistent movements movement substitution inability to complete movement

Question 62

what factors influence muscle fatigue?

Answer 62

health status diet lifestyle environment factors

Question 63

proteins in elderly are ___

Answer 63

reduced

Question 64

vitamin D influences what 2 things?

Answer 64

type 2 muscles fibers and NTs

Question 65

what is the role of B12 and folic acid in muscles?

Answer 65

correct homocysteine levels associated with CV disease, lower quad strength, and gait speed

Question 66

how does reduced acid-producing diet affect muscle?

Answer 66

an acid-producing diet stimulates muscle catabolism

Question 67

antioxidants can reduce what in elderly?

Answer 67

sarcopenia