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final exam: chapter 19&20- performance
Terms in this set (44)
what are the 2 possible sites of fatigue?
1. central (10%)
2. peripheral (90%)
what consists of central fatigue?
brain, spinal cord, and peripheral nerves (occurs before NMJ)
what consists of peripheral fatigue?
neural, mechanical, bioenergetics (at level of NMJ and deeper)
what results from central fatigue?
a decrease in motor unit activation and firing rate
what happens when you have central fatigue?
- prolonged fatigue
- altered mood states
- sleep disturbance
- loss of appetite
- increased anxiety
what is a big cause of central fatigue?
how can we overcome central fatigue?
- increase or motivation
- physical or mental diversion (play music)
- have more carbs might help delay central fatigue
explain the serotonin, dopamine ratio
we want high levels of dopamine because this is what motivates you to "finish that race". we want low levels of serotonin because this is what tells us we're tired and to give up
what are the 3 areas we see peripheral fatigue?
3. energetics of contraction
what are the reasons for fatigue in neural factors?
as we become fatigued during exercise, our Na/K muscle pump gets tired and overused. because of this, Ca+ can not be released from the SR meaning less muscle contraction occurs. an accumulation of K+ also results from this and prevents depolarization
what are the reasons for fatigue in mechanical factors?
- at increased intensities of exercise, we rely on glycolysis which causes us to accumulate H+. when we accumulate H+, this inhibits Ca from being released and binding to troponin
- H+ also reduces enzymes abilities
- physical disruption of sarcomeres (have been ruptured and muscles can't contract)
what are the reasons for fatigue in energetics of contraction factors?
- when we become fatigued, there is a longer "relaxation" (repolarization) time
- trained individuals have shorter relaxation times
these performances last less than 10 seconds
what are the limiting factors that cause fatigue in ultra short performances?
- motivation, skill
- ATP-PC system, and glycolysis
what may help improve ultra short performances?
taking creatine because it allows ATP to be generated quickly
events lasting 10-180 seconds (tennis, volleyball)
short term performances
what are the limiting factors that cause fatigue in short term performances?
pH, H+ accumulation (#1 source of ATP is glycolysis and with glycolysis we accumulate lactate and H+ ions which can cause fatigue quicker)
what can help improve short term performances?
ingestion of buffers (sodium bicarbonate)
events lasting 3- 20 minutes
moderate length performances (basketball, soccer)
what are the limiting factors that cause fatigue in moderate length performances?
vo2 max (want highest SV and o2 content possible)
what can help improve moderate length performances?
endurance training can help increase SV (CO) and a-vo2 difference which are keep components in increases vo2 max
events lasting 21-60 min (10k)
intermediate length performances
what are the limiting factors that cause fatigue in intermediate length performances?
1. vo2 max
2. running economy (want high % of type 1 fibers/technique of running)
3. environmental factors (heat and humidity decrease performance)
4. state of hydration
events lasting longer than 4 hours (marathon, triathalon)
long term performances
what are the limiting factors that cause fatigue in long term performances?
carbohydrate stores (during long distance events, athlete is at risk for depleting muscle glycogen stores)
what can help improve long term performances?
1. ingestion of carbs
2. consumption of fluids and electrolytes
what is interval training?
- has work and rest periods (work around 60 seconds)
- can be advantageous over continuous exercise due to overload principle
- there is increase in mitochondria and antioxidants (causes an increase of PGC1-A)
what does PGC1-a stand for?
peroxisome proliferator-activated receptor-gamma coactivator
what is HIIT interval?
- more advantageous than continuous
- is a category of interval training
- also increases PGC1-a
what is long-slow distance training?
- low intensity exercise
- if training for event, want the duration to be greater than the actual event
why is HIIT better for training for events?
there is an increase in SV, contractility, mitochondria (PGC1-a), and fat met.
what is high intensity, continuous training?
train at or slightly above lactate threshold (high intensity) for longer period of time (3 min)
does altitude training imrpove performance at sea level?
live ____ train _____
live high, train low
why should you live high?
it increases RBC volume and o2 transport to blood
why should you train low?
you can train at higher intensities
how can you anaerobically train to improve power?
10-90 sec quick activities/speed training
how can we improve our ATP-PC system anaerobically?
implement work-rest intervals
how can we improve our glycolytic system anaerobically?
- have longer work and rest periods
- may deplete muscle glycogen levels so it is good to alternate training days
how does endurance training interfere with protein synthesis?
via inhibition of mTOR
what does the decrease of protein synthesis depend on?
- training state
- intensity, volume, modality and frequency
what should you do to optimize strength gains while also wanting to endurance train?
- alternate days
- 6h in between exercises
what is the main factor in endurance training that inhibits mTOR (protein synthesis) signaling?
AMPK which increases PGC1-a which inhibits mTOR
how does strength training promote muscle strength gains?
it increases more mTOR signaling. when mTOR is activated it increases protein synthesis, muscle mass, and strength
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