Injury and Repair Flashcards
muscle injury can result from
- disease
- myotoxic agents
- trauma (sharp/blunt/surgery)
- ischemia
- hot/cold temps
- contractions (esp. eccentric)
do you gain force after an initial injury
yes
does peak CK occur before or after peak tenderness
after
when is peak soreness post exercise
24-48 hrs
when is peak CK post exercise
5-7 days
when is peak strength post exercise
1-24hrs post
when is peak acute inflammation post exercise
1-12hrs
when is peak chronic inflammation post exercise
5-7 days
how long does it take muscles to recovery from a heavy lift
about a week, only train that muscle group at that intensity once a week
what are some changes after injury
- z-line changes
- necrosis and infiltration of inflammatory cells
- damage repaired by regeneration of fiber damage (takes time)
what is some things that happen with structural damage
- myofibrillar disruption (z-line periodicity lost)
- sarcolemma disruption
- swelling and disruption of the sarcotubular system
- damage to the cytoskeleton (desmin)
- abnormalities in the extracellular matrix
biochemical events with contraction-induced injury
- increased cytosolic ca+
- digestion of myofibrillar proteins and phospholipids (damaged proteins)
- inflammatory response (macrophages, IL1, IL6, TNFa, free radicals)
DOMs is…
muscle pain
occurs with lengthening contractions and high-force isometric contractions when the muscle is at a long length
DOMs stiffness may be related to…
edema
DOMs tenderness may be related to…
inflammatory response
T or F: lactate causes muscle pain not DOMs
lol, no. false
what is protection against contraction induced injuries
trained muscle will protect itself and avoid injury
what are some sources of externally caused muscle injury
- trauma.crush
- biological toxins
- local anesthetics
- diseases
biochemical events with externally caused injury
- necrotic zones
- increased ca+
- Ca+-activated proteases, complement components, macrophages
- formations of stumps (anchor points)
- mononeuron sprouting
________ cells proliferate and migrate
satellite
________ cells differentiate into myoblasts which fuse into myotubes
satellite
T or F: satellite cells offer genetic control of cell proliferation, differentiation, fusion, and synthesis of muscle specific proteins
T
T or F: (satellite cells) myotubes bridge stumps
T
how many days after a crush injury do you see a plateau of healing
20
what are some signals for muscle repair
cytokines: IL1, IL6, TNFa
growth factors: IGF1, IGF2, FGF
healing of skeletal muscle day 2
- macrophages are removing necrotized parts of the damaged fibers
- fibroblasts have begun to form the connective tissue scar in the central zone
healing of skeletal muscle day 3
- within the regeneration zone, satellite cells have become activated within the basal lamina cylinders
healing of skeletal muscle day 5
- connective tissue in the central zone has become more dense
- myoblasts have fused into the myotubes in the regenerative zone
healing of skeletal muscle day 7
- regenerating muscle cells begin to pierce the scar by extending out of the old basal lamina cylinders
healing of skeletal muscle day 14
- the regenerating fibers close the central zone gap
- the scar of the central zone has condensed further and is reduced in size
healing of skeletal muscle day 21
the fibers have fused with little scar (connective tissue) in between
Should we focus on immobilization or mobilization for fibrosis?
early mobilization is important
what is myositis ossificans
- bone/ca+ deposits in muscle after a hard impact
- high contact sports or hemophillia/other bleeding disorders in conjunction with soft tissue injury
COX enzymes form prostaglandins which play a role in __________
inflammation
in skeletal muscle, prostaglandins participate in regulation of ____________
protein synthesis
__________ is responsible for baseline levels of prostaglandins, ________ increases prostaglandins upon stimulation
COX1
COX2
_________ inhibit both COX1 and COX2
NSAIDS (ibuphrofen and aspirin)
newer INSAIDS (vivoxx, celebrex) target only ________-
COX2
___________ reduces hypertrophy of overloaded muscles
ibuprofen
NSAIDS ________ protein synthesis
decrease
T or F: in the short term, NSAIDS increase force but in the long term hinders the healing process
T
short term NSAID use results in
less soreness
less force decline
less inflammation
maybe less protein synthesis
long term NSAID use results in
less force recovery
less fiber regrowth
T or F: satellite cell number is blunted with NSAID use
T
T or F: long term NSAID use blunts long-term skeletal muscle hypertrophy in chronic mechanical overload in rats
T
what happens in the inflammatory phase of tendon repair
- phagocytosis of necrotic debris
- tenocytes proliferate
what happens in the proliferative phase of tendon repair
synthesis of type 3 collagen (type 3 can be laid down faster but is weaker)
what happens in the consolidation stage in the remodeling phase of tendon repair
- tissue changes from cellular to fibrous
- type 1 collagen is synthesized
what happens in the maturation stage in the consolidation phase of tendon repair
fibrous tissue changes to scar-like tendon tissue
muscle, lig, tendon: which heals fastest?
muscle, tendon, then ligament
*blood supply issue
