Unit 2 Muscle and Tendon Injury Flashcards
What percentage of body mass is muscle?
40-50%
what is the myotendinous junction?
common place for strain
where the muscle proper is merging with the tendon proper
what is the basal lamina?
scaffold for healing
what are satellite cells?
muscle stem cells that help with regeneration of muscle
what factors affect muscle performance under load?
age, temperature, immobilization or disuse
what are some MOIs for muscle tissue?
excess strain/stretch, excess tension, blunt force/contusion, laceration, thermal stress, myotoxic agents, disease, new exercise/activity, prolonged disuse/immobility
what are the 3 phases of muscle healing? and what phase of healing do their correlate to?
destruction (hemostasis/inflammation), repair (proliferation), remodeling (remodeling)
what is happening in the destruction phase of muscle healing?
necrosis of damaged muscle tissue
factors released, start hemostasis and inflammatory response
vascular disruption - hematoma and edema begin
leukocytes infiltrate and activation/proliferation of satellite cells (myoblasts)
what is happening during the repair phase of muscle healing?
hematoma formed
inflammatory cells arrived and satellite cells proliferation continues
new myofibers are joined
neuromuscular junction reestablished as close to the original motor point as possible
what is happening in the remodeling phase of muscle healing?
regenerated tissue matures and tensile strength increases
scar contracts and is reorganized
type 1 return to normal proportion over type 3
what causes a contusion? and what can a contusion lead to?
blunt trauma; hematoma
what are the two types of hematoma?
intermuscular and intramuscular
what is myositis ossificans?
severe contusion can result in a calcified hematoma where calcium forms in the hematoma like little pieces of bone
what are the risk factors for a strain?
inadequate flexibility, inadequate strength and endurance, muscle imbalances, insufficient warm-up or fatigue, inadequate rehab from past injury
what is a distractive strain?
excess pull, overstretch
where does most of the damage occur in a muscle strain?
at the MT junction with immediate pain
what is DOMS?
delayed onset muscle soreness due to unaccustomed exercise (especially eccentric)
metabolic products and subcellular damage
what is the effect of high force concentric contraction?
reduction in force by 10-30% lasting for hours
what is the effect of high force eccentric contractions?
reduction in force by 50-65% lasting 1-2 weeks
what tissue changes are occurring with eccentric contractions?
damage to sarcomere, disruption of ECM, intramuscular edema, increase creatinine kinase (this signals muscle breakdown)
describe the differences of the 3 grades of muscle strain.
grade 1: tear only few musculotendinous fiber, pain only with limited swelling, no loss of function
grade 2: disruption of moderate number of fibers, increased pain, some loss of strength and function
grade 3: complete rupture of some musculotendinous units, loss of function with little pain, at the MT junction site
why does a grade 3 muscle strain have less pain?
if the two ends are no longer connected there can’t be a force in that area that is perceived as painful
what are the clinical signs of a muscle injury?
sudden onset/traumatic
pain most pronounces during eccentric activation
localized tenderness over myotendinous junction
possible swelling and ecchymosis (due to hematoma)
AROM (sometimes PROM) of associated joint may be restricted and painful with guarding and empty end feels
resisted strength testing is weak and painful (weak due to pain)
what can you do for muscle injury management in the protective phase?
PRICEMEM, pt education
PROM, AAROM, AROM
what can you do for muscle injury management in the controlled motion phase?
AAROM, AROM, flexibility
submaximal isometrics -> multiangle submax isometrics -> multiangle max isometrics -> PREs
simple/safe balance, proprioception activities
corrective exercise of associated biomechanical deficiencies