Enery Transfer During Exercise Flashcards
Energy output on sustained exercise is …….X more than at rest
20-30X
The contribution of different energy transfer systems differs depending on…? (3)
Intensity of exercise
Duration of exercise
Fitness of participant
Immediate energy is attained from what system?
ATP - PCr system
In the ATP-PCr system, what provides energy supply?
Intramuscular high energy phosphates:
ATP - Adenine Triphosphate
PCr - Phosphocreatine
How much ATP and PCr does 1kg of skeletal muscle contain?
3-8mmol ATP
X5 more PCr
Energy output in sprint running and swimming is ……X more times than at rest
120X
For a 70kg person with muscle mass of 30kg, how much high energy phosphates?
570-690mmol
Enough stored energy exists to:
Run at marathon pace for….s
Sprint for ….s
Walk briskly for….s
Marathon for 20s
Sprint for 5-8s
Walk briskly for 60s
Which has a higher rate of energy transfer? Energy from intramuscular high energy phosphates or aerobic metabolism? And by how Much?
High energy phosphates - 4-8 times faster
Where does energy for ATP replenishment come from?
Macronutrients in tissues and cellular fluid
How is Intracellular metabolism measured?
Explain.
Advantage of this technique
How are results interpreted?
Nuclear Magnetic Resonance (NMR)
Uses magnetic field to identify chemical compounds in tissues
Not as intrusive as biopsy techniques
Results interpreted by looking at the ratio of inorganic phosphates (Pi) to PCr
Which system is short term energy supply from?
The lactic-acid system
In order for high intensity, strenuous activity to continue.. What must happen?
Rapid re-synthesis of high energy phosphates
To phosphorylate ADP to ATP, energy comes from……. …….via …….. ……..
Muscle glycogen via anaerobic glycolysis
Which has a higher rate of energy transfer? Energy from intramuscular high energy phosphates or anaerobic metabolism? And by how Much?
HEP’s - Energy transfer rate in anaerobic glycolysis is only 45% of high energy phosphate rate
Product of anaerobic glycolysis
Lactate
Anaerobic glycolysis can be viewed as a …….. Fuel
Reserve
Why is warming down important after anaerobic exercise?
Minimises lactic acid accumulation
Factors influencing lactate threshold? (4)
Low tissue O2
Reliance on glycolysis
Activation of fast twitch muscle fibres
Reduced lactate removal
Blood lactate accumulates at every level of exercise intensity. True or False?
False. Only at moderate and above
Why doesn’t lactate accumulate at light intensity exercise?
O2 consuming reactions meet the energy demanded. Any lactate becomes rapidly oxidised. Lactate production = lactate oxidation so levels remain stable.
As a % of VO2max, what is the lactate threshold for a healthy untrained person?
55% VO2max
Hypoxia is..
A lack of oxygen in tissues
Effects of hypoxia on the cells
Lack of 02 & production of NADH above cells capacity means that electrons/ hydrogens can’t be shuttled down respiration chain.
Pyruvate then accepts the electrons/ hydrogens instead which creates LACTATE
Relationship between fast twitch and slow twitch muscle fibres with lactate and pyruvate?
Enzyme involved
Why does this relate to exercise intensity?
In FTMF, lactate dehydrogenase favours the conversion of pyruvate to lactate
In STMF, lactate dehydrogenase favours the conversion of lactate to pyruvate,
More FTMF recruited as exercise intensity increases
In elite athletes, does lactate threshold occur at a higher or lower % of their aerobic capacity?
At what %?
How can this be influenced? (3)
Higher.
80-90%
Training adaptations
More rapid rate of lactate removal
Genetic endowment
How does endurance training effect mitochondria, aerobic & metabolism
Increases size and number of mitochondria
Increases the number of enzymes involved in aerobic metabolism which improves the ability to make ATP with fatty acid and glucose catabolism
How can having a low lactate level extend the duration of high intensity aerobic exercise?
Conserves glycogen reserves
LONG TERM ENERGY:
Which system?
Aerobic system
When is the long term / aerobic system used?
Why?
When exercise lasts beyond several minutes
As glycolysis doesn’t make much ATP
Any lactate produced in the aerobic system reconverts to ………. Via the ……… ……… In the ………..
Glucose
Cori cycle
Kidneys/liver
Blood lactate doesn’t accumulate during steady rate ,metabolic conditions. TRUE OR FLASE?
True
Theoretically a person could continue to exercise indefinitely if they had the will power. However, is assumes that …… ……. ……. …….. Is the only determinant. What are the limiting factors? (3)
Fluid loss
Electrolyte depletion
Maintenance of muscle glycogen (for exercise) and liver glycogen (for CNS)
Fast twitch muscle fibres (2)
Contraction speeds
Capacities for glycolysis
Type IIa,
Rapid speed
Highest capacity
Type IIb,
Rapid speed
High capacity
Type II fibres:
When do they become active?
They contribute to an increased …….. …….. When maintaining a constant speed during maximum effort movements
Depend solely on energy from ……..?
During change of pace and stop and go activities
Force output
Anaerobic metabolism
Elite sprint runners possess ….% of FTMF
80%
Slow twitch muscle fibres:
AKA
Contraction speed
Generate energy through …….. Pathways due to (2)
When are they used
Predominance of Slow twitch muscle fibres contribute to …..
Slow contention speed
Aerobic pathways due to (1) numerous enzymes (2) large mitochondria
Sustain continuous activities that need a steady state of aerobic energy transfer
Contributes to high blood lactate thresholds
ElIte endurance runners possess ….% STMF
80%
