MSK Flashcards
what are the age related changes that we see in muscle with older adults
the cross sectional area of the muscles is reduced
fewer motor units to recruit - loss of motor neruons in the ventral horn of the spinal cord
how does a decrease in the cross sectional area of the muscle impact the muscle
less force is produced - less muscle to produce this force
what is the response of resistance training in older adults
increased recruitment much more then muscle hypertrophy
when does decreased muscle force production start
45
more rapid at 70
LE>UE
decreased cross sectional area is realted to the loss of what kind of fibers
fast twitch fiber area
slow twitch remain while fast decrease
what is muscle mass
how much muscle fiber is present
what is muscle strength
the ability to generate max muscle force
what is muscle power
the product of the force the the velocity of the contraction (time)
what characteristic of muscles is best at predicting disability
muscle power/ muscle strength
- we can lose a lot of strength and still walk fine, walking does not use much strength
what does a loss of muscle power limit
stair negotiation
getting up from chairs
do our capillaries change size as we age
no in active elderly
sedentary elderly - have a decrease in capilliziation
what implication does decreased capillierization have
the decreased ability to shunt blood to active tissues - reduced effectiveness of vasodilation with activity
do we see changes with anerobic/aerobic dilation with aging
no
slight for aerobic - sedentary adult 20-30% change
what happens with aged cartilage
it cannot hold its water
- aggrecan (protoglycan of art cart) cannot hold its water
- hydrostatic lubrication is impaired, we will lose protection against compressive forces
what do chnages in the cart lead to
cracking and fribrillation
this disrupts the binding of fribonectin and lamin
the cart is exposed to degenerative enzymes - contributes to OA
why is the collegen in older adults rigid
the collagen is less souble, have cross linkages to stabilze it therefore it is more rigid
what happen to the elastin in older adults
less is produced
more is fragmented
result:
- greater chance of rupture
- loss of rebound property
what part of the body do we find elastin fibers
alveoli
aorta
lig flavum of the spine
why do we see bone demineralization in older adults
reduced bone formation
age: reduced ability to make bone, bone formation is bad
postmenopausal women: bone reabsorption faster then bone formation
what are the three factors to stimulate bone formation
WBearing
circulation
muscle contraction
can exercise impact age related bone loss
yes but it takes a lot of exercise
impact activties and bone formation
large loads
rapid changing directions
endocrine impacts of exercise
exercise enhances insulin sensitivity, glucose metabolism, and some mito function
