neuromuscular fatigue - effect of exercise Flashcards
what is the effect of fentanyl injections on peripheral fatigue
blocks III/IV afferents (usually preventative mechanisms for us)
brain doesn’t perceive pain and can go harder therefore significantly increases peripheral fatigue
- less central fatigue because the brain doesn’t receive signals from III/IV afferents
what is the amount of peripheral fatigue in small vs large muscle groups
small = more peripheral fatigue
large = less peripheral fatigue
what is the amount of central fatigue in small vs large muscle groups
small = less central fatigue
large = more central fatigue
why do small muscle groups cause less central fatigue
less III/IV afferent receptors so brain doesn’t receive as much sensory feedback
- brain keeps driving muscle
why do large muscle groups cause more central fatigue
lots of afferents going to the brain
brain feels bad faster
muscle is held back and exercise is terminated sooner
why does MVC decline more in single leg exercises
more peripheral faitgue
large muscle is prevented from performing at max because of sensory feedback
what is ensemble afferent feedback (maximal sensory tolerance limit)
capacity of the brain to tolerate an exercise induced rate of fatigue, pain, and exertion
- everyone has a sensory tolerance limit (individual limit)
how much exercise would you have ot do on one leg vs two to reach max sensory tolerance
singel leg would have to do double the exercise to reach the same amount of afferent signal
what is the role of exercise intensity duration in central and peripheral fatigue
high intensity short duration = greater peripheral fatigue
low intensity long duration = greater central fatigue
which exercise intensity takes the longest to recover from
moderate exercise
- depletion of muscle glycogen
what causes the decline in twitch after severe exercise
accumulation of metabolites (H+ and Pi)
why does an increase in Pi cause decreases in performances
can bind to Ca2+ inside the sarcoplasmic reticulum
reduces the free Ca2+ availability
can’t activate afferent feedback because Pi is inside the cell and III/IV afferents are outside the cell
what causes the reduction in voluntary activation after moderate and severe exercise
changes in blood glucose or central temperature
