6.2 Metabolic Adaptations to Endurance Training Flashcards
what is the Respiratory Exchange Ratio
Ratio between the vol of CO2 being
produced by body and amount of O2 being consumed.
Respiratory Exchange Ratio (RER) equation
R = VCO2 / VO2
what is VO2 + VCO2
V02 - o2 uptake
VCO2 - CO2 output
what does Respiratory Exchange Ratio do
Value gives indication as to whether body is operating aerobically or anaerobically.
what is The Crossover Concept
Describes relative balance between CHO & fat metabolism during sustained exercise.
The Crossover Concept at rest/ during exercise
below ~60% of VO2max, fats main
ATP-generating substrate
The Crossover concept during high-intensity exercise
(>75% of VO2max), ↑ in
glycogenolysis & recruitment of more type II muscle fibres promote shift to CHO as predominant ATP-generation source.
Crossover point:
intensity where fat and CHO utilisation intersect (where energy from fat decreases and energy from CHO increases).
Crossover point impacted by:
exercise intensity & endurance training status.
* Endurance exercise training can shift crossover point towards higher intensities
Metabolic Adaptations:
Reduced (RER)
Reduced respiratory exchange ratio at rest and during exercise
Respiratory Exchange Ratio PT
greater oxidation of fat relative to carbohydrate
Increased Fat Oxidation RER
(1) Greater uptake and utilisation of
plasma fatty acids
(2) Increased utilisation of intramuscular triglyceride
Increased Fatty Acid Uptake by Muscle
Uptake of fatty acids is proportional to plasma fatty acid conc
BUT trained individuals can transport more fatty acids into muscle with a lower plasma fatty acid conc
(Increased Utilisation of Intramuscular Triglyceride)
trained person plasma fatty acid
concentration
lower
trained person capacity of fatty acid transporter in cell membrane
increased
