Limits to exercise tolerance 1 Flashcards
What is fatigue?
The inability to maintain power output or force during repeated muscle contractions
Which test could be done to assess exercise performance?
VO2max or VO2peak
Which test could be done to assess exercise capacity?
Time to exhaustion
What are the three exercise intensity domains?
Moderate, heavy, severe
What level of exertion is moderate?
Anything below lactate threshold/gaseous exchange threshold
When is lactate threshold reached?
When the production of lactate is occuring at a faster rate to the removal rate
What intensity of exercise is heavy?
Between lactate threshold and critical power/critical speed
What intensity exercise is severe?
Anything above critical power/critical speed
How is critical power tested?
VO2max test, record highest power output (wattage) from that. Then have them do several time to exhaustion tests with the resistance of the bike being different %s (500, 100, 50 etc) of their VO2max test. Measure the time they can go until exhausiton against these different %s. Can plot a curve which will flatten (after going down). Flattened curve is intensity that the person can maintain for a long period of time
What are the likely fatigue mechanisms for moderate exercise?
Hyperthermia, mental fatigue and muscle damage
What are the likely fatigue mechanisms for heavy exercise?
Glycogen depletion and hyperthermia
What are the likely fatigue mechanisms for severe exercise?
Depletion of finite energy stores (W’)
Which three elements dictate performance velocity or power?
Performance VO2, Performance O2 deficit, Gross mechanical efficiency
What can limit performance VO2?
Lactate threshold, muscle capillary density
What can limit lactate threshold directly?
Maximal oxygen consumption, aerobic enzyme activity, distribution of power output
What can limit maximal oxygen consumption directly?
Muscle capillary density, stroke volume, max heart rate, hemoglobin content
What directly influences performance O2 deficit?
Total buffering capacity and distribution of power output
What is total buffering capacity?
How good our muscles are at buffering acidosis
What is acidosis?
Acid build up in the muscles as a result of exercise
What can affect performance O2 deficit and performance VO2?
Distribution of power output
How can total buffering capacity be changed?
Training status and nutrition
Which compound can improve total buffering capacity during exercise?
Sodium bicarbonate
Why can taking sodium bicarbonate help with high intensity exercise?
It can help with buffering of acidosis
What can influence gross mechanical efficiency?
% slow twitch (type I) muscle fibres, anthropometry and elasticity
