kin 202 - fatigue mod 8

fatigue

reversible decline of muscle performance during activity due to muscles becoming weak and slower for decreased power, shortening velocity, force and relaxation

true

more recovery from fatigue occurs within the first hour

\
t or f

slow component

________________ of fatigue takes days to reverse

injury

decline in muscle performance that reverses slowly and characterized by sarocmeric disorder, membrane damage and inflammation, satllite cells and damaged fibers

eccentric

injuries are common in ____________ contractions

voluntary contraction

person physically moves muscle groups

involuntary contraction

electrical stimulus is used

decreases

what happens to contraction velocity after a wingate

fast-twitch

_____________ muscle fibers will experience a larger reduction in velocity and power due to fatigue

slow twitch

_______________ muscle fibers will experience a smaller reduction in velocity and power due to fatigue

true

fatigue causes a decrease in rate of contraction

false

fatigue causes a increase in rate of relaxation

false

fatigue causes a increased rate of force production

\
t or f

true

fatigue causes a decrease in peak tension

\
t or f

false

fatigue causes a decrease in contraction time

level one mechanism

where does the failure occur with respect to excitation-contraction coupling and relaxation processes that causes decline in muscle performance

central fatigue

deficit from the neuromuscular junction and up (cortex)

peripheral fatigue

everything associated with the muscle, from sarcolemma inwards

level two mechanism

what causes impairment or failure of particular E-coupling process or what mechanism was associated with the other mechanism

metabolic

_________________ level 2 mechanism can be reduced energy supply and/or accumulation of metabolic by-products

non-metabolic

__________________ structural damages from level 2 mech. involve free radicals and activation of proteolytic enzymes

decreases

what happens to ATP post exercise

increases

what happens to Pi conc. after exercise

increases

what happens to ROS activity after exercise

cytosol

a mechanically skinned muscle fibre allows you to manipulate what is in the ___________

true

structural damage to heavy resistance exercise and eccentric contractions are common

\
t or f

aerobic capacity of muscle fibre

fatigue develops rapidly when exercise requires AP production exceeding ___________________

actomyosin crossbridges

decreased ability of ___________________ to make force contribute to acute fatigue

true

reducing the myofibrillar Ca2+ sensitivity can cause acute fatigue

\
t or f

true

decreased SR Ca2+ releaseis only really important in later stages of fatigue

\
t or f

RyR agonist

caffine is an example of __________________ which helps RyR activate and release to restore force

shifts right

if there is a decrease in myofibrillar Ca2+ sensitivity, what happens to the myoplasmic \[Ca2+\] - force curve

change in ca2+ release

a movement along a single curve on the myoplasmic \[ca2+\] force curve indicates what

shifts left

if ca2+ release from SR is reduced, what happens to the myoplasmic \[ca2+\] force curve

shifts right

if there is an increase in Ca2+ release from the SR, what happens to themyoplasmic \[ca2+\] force curve

shifts down

if there is a decrease in force per cross bridge what happens to the myoplasmic \[ca2+\] force curve

false

lactic acid is a major cause of fatigue

\
t or f

true

acidosis does not affect max tetanic force during the first or last contraction

\
t or f

false

number of tetanic contractions required to induce fatigue is affected by acidosis

\
t or f

true

rate of relaxation is reduced during acidosis

\
t or f

increases

what happens to cytosolic \[Pi} during exercise

Ca2+-Pi percipetate

when Pi enters the SR what is formed

decreased

what happens to the amount of Ca2+ released when a calcium Pi precipitate forms

sigmodial

what is the graph shape of a calcium conc. vs relative force

true

with more Pi making precipitates with calcium less force is made

\
t or f

ATP

most of Mg2+ in a skeletal muscle is bound to ____

increases

high rates of ATP hydrolysis ____________ free Mg2+ in cytosol

true

Mg2+ is a potent inhibitor of RyR

decreases

what happens to calcium release when the Mg2+ conc goes from 1 to 3

false

there is no physical link betwen the DHPR and the RyR

\
t or f

depolarization

___________________ causes DHPR to change shape to open RyR for calcium release

junctophilin

the protien that physically connects the DHPR and RyR

proteolytic enzymes

calcium at high or low conc. for long period of time will activate _______________ to break down junctophilin

glycogen

____________________ has a strong correlation b/w time to exhaustion and resting conc.

true

depletion of glycogen severely impacts exercise capcity

\
t or f

SR Ca2+ release

there is a correlation /w reduced _____________ and depletion of intramuscular glycogen after repeated tetanic stimulation

ROS / RNS

unstable molecules that react easily with other molecules in a cell

signaling molecules

in low to moderate conc, ROS or RNS act as _______________ to change 3D structure

false

all ROS/RNS is bad at any level of conc.

\
t or f

increase in Pi

maximum Ca2+ activated force is reduced by _____________

Pi, ROS/RNS

Ca2+ sensitivity of myofibrillar proteins is reduced by increase in _____________

pH

Ca2+ sensitivity of myofibrillar proteins is reduced by decrease in __________