Flashcards
Physiology revision
Flashcards do conjunto (5)
- 1Describe PCr depletion as a cause of fatigue in a 100m sprint- As pcr depleted, ability to quickly replace spent ATP hindered
- Use of ATP continues, but ATP-PC system less able to replace it so ATP decreases
- e.g 100m sprint, Pi which ^ during short-term insense ex due to breakdown of PCr is potential cause of fatigue
- Intervention to reduce fatigue = creatine supplementation
-Fatigue also delayed by the athlete controlling the rate of effort through proper pacing to ensure PCr + ATP are not prematurely exhausted - 2Describe glycogen depletion as a fatigue mechanism during an event lasting longer that a few seconds- Muscle glycogen primary source for ATP
- Glycogen reserves are limited and become depleted
- Muscle gly used more rapidly during first few minutes of ex than in later stages
- Severe fatigue perceived when muscle gly stores nearly depleted
- Sensation of fatigue in long-term exercises coincides with a decreased concentration of muscle glycogen, but not with its rate of depletion
- E.g marathon runners refer to 'hitting the wall' at 18-22 miles - 3Describe glycogen depletion and blood glucose as a mechanism of fatigue during prolonged exercise- Muscle gly alone can't provide enough CHO for exercise lasting several hours
- Glucose delivered by blood to muscles is needed in endurance events
- Liver gly stores are limited, liver can't produce glucose rapidly from other substrates
- As a consequence, blood glucose levels can decrease when muscle uptake exceeds livers glucose output
- Muscles then unable to obtain sufficient glucose from the blood so rely more heavily on their gly reserves which accelerates muscle gly depletion + leads to earlier exhaustion
- E.g in events lasting longer than 60-90 mins
- Intervention = CHO loading - 4Describe the metabolic by product of heat and muscle temperature as a mechanism of fatigue- Heat production is retained by the body + causes core body temp to rise
- Exercise in the heat can increase the rate of CHO utilisation + hasten glycogen depletion - 5Describe lactic acid , hydrogen ions and their role in fatigue- LA accumilates within muscle fibre during anaerobic glycolysis
- Uncleared LA dissociates + converts to lactate causing an accumilation of H+ ions
- H+ acculimation causes muscle acidification (acidosis)
- e.g 100m/200m sprint
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- FlashCards sobre Physiology revision, criado por samb008 em 14-04-2014.
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