Exercise Physiology

1. Anaerobic capacity testing
Dr Noorin Bhimani
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2. 2
Anaerobic Energy Systems
• Anaerobic energy system = energy system within
the body that does not require the use of oxygen
• It consists of the ATP-PC system and the Lactic
Acid/Anaerobic Glycolysis system
• All three energy pathways (ATP-PC, Lactic Acid &
Aerobic energy systems) operate at any one time
and can overlap. The contribution of each varies
depending on the duration and intensity of the
activity

3. 3
Anaerobic Energy Systems
ATP-PC SYSTEM
• Provides a bulk of ATP required during powerful and
explosive efforts
(Eg: take off in high jump, sprint position in netball)
• Linked with several fitness components
(Eg: muscular strength, anaerobic power, speed)
• Provides up to 10 seconds of energy for maximal effort
• The system relies on muscle stores of both ATP and PC
(phospho-creatine)

4. 4
Anaerobic Energy Systems
LACTIC ACID SYSTEM
• Provides bulk of ATP production during high
intensity, sub-maximal efforts.
• Operates as a dominant supply of ATP from around
15-60 seconds of maximal effort
• Closely linked with several fitness components
(Eg: anaerobic power, speed and muscular power)
• Classic example: 400m run

5. 5
Definitions
• SPEED: Refers either to the
ability to perform a
movement quickly or to
see how fast a movement
is performed.
• POWER: The rate of
performing work. The
product of force and
velocity. Power = force x
distance/time.

6. 6
Definitions
• WORK: Physical work or
effort as opposed to rest
• VELOCITY: Velocity =
distance/time. How fast an
object is moving at any one
time over a given distance
with regard to direction.
Two types: Linear and
Angular.

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Post Exercise Oxygen Consumption
(EPOC)
• When aerobic exercise begins, the oxygen transport
system does not immediately supply the needed
quantity of oxygen to the active muscles because
oxygen consumption requires several minutes to
reach steady state.
• Because oxygen needs and oxygen supply differs
during the transition from rest to exercise, the body
incurs an oxygen deficit. (eg: getting tired during
warm up)

8. 8
Post Exercise Oxygen Consumption
(EPOC)
• The oxygen deficit = the difference between the
oxygen required for a given exercise intensity and
the actual oxygen consumption.
• Excess Postexercise Oxygen Consumption (Oxygen
debt) = the elevated levels of oxygen consumption
during the initial minutes of recovery, which exceed
the oxygen usually required at rest.

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Post Exercise Oxygen Consumption
(EPOC)

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Sources of Fatigue
• PCr depletion
• Muscle glycogen depletion
• Neuromuscular - nerve impulses
• CNS - muscular recruitment
• Metabolic by-products
- Lactate
- Hydrogen Ions – low ph
- Buffers - bicarbonate

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Metabolic By-Product Removal
LACTIC ACID:
• Myth – that lactic acid is responsible for fatigue
• Truth – lactic acid accumulates within the muscle fibre only during
relatively brief, highly intense muscular effort.
• Truth – fatigue is generally caused by inadequate energy supply
• Lactate – Removed by Gluconeogenesis (conversion of
glucose) through Cori cycle (energy consuming) or the
Oxidation to pyruvate which fuels the citric acid cycle
(energy producing)

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Metabolic By-Product Removal
HYDROGEN IONS
• Hydrogen Ions (pH) – Removed by buffers
such as bicarbonate
• pH is a major limiter of performance and the
primary cause of fatigue during maximal and
all-out exercise

13. Anaerobic power and
anaerobic capacity
• Anaerobic power: Peak rate of ATP produced via
anaerobic metabolism, difficult to measure
directly
– Usually estimated from peak power output during
all-out sprint-type exercise
• Anaerobic capacity : Maximal amount of ATP
that can be generated through anaerobic
metabolism, during short-duration maximal ex
– Important for 400-1500 m running, 200-400 m
freestyle swimming, 1-4 km track cycling, 2000 m
rowing, 500-1000 m kayaking, team sports
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14. Measure anaerobic ATP production
• Muscle biopsy : Changes in muscle metabolites
• Blood lactate after supramaximal exercise
• Oxygen debt after supramaximal exercise
• Total work or mean power output during short-
duration maximal exercise
– Wingate test (30 s all-our cycling), 9-40% ATP
produced aerobically
– Tests < 60 s inadequate to exhaust anaerobic system
• Accumulated oxygen deficit
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15. Rest-to-Exercise Transitions
• Oxygen uptake increases rapidly
– Reaches steady state within 1-4 minutes
• Oxygen deficit
– Lag in oxygen uptake at the beginning of
exercise
– Suggests anaerobic pathways contribute to most
ATP production
• After steady state is reached, ATP
requirement is met through aerobic ATP
production
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16. The Oxygen Deficit
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17. Differences in VO2 Between Trained
and Untrained Subjects
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18. accumulated oxygen deficit
• At submaximal exercise: O2 consumption meets
energy demand at steady state, aerobic metabolism
– Linear VO2-power output relationship
• Supramaximal exercise: required ATP from aerobic +
anaerobic metabolism
– Exercise performed at a power output higher than that
achieved at VO2peak
– <60 sec sprint, or 2-4 min at constant power output
– Accumulated oxygen deficit = calculated accumulated
oxygen demand – measured accumulated oxygen demand
• MAOD: maximally accumulated oxygen deficit
– Valid and reliable measurement for anaerobic capacity 18

19. Assumption and criteria for MAOD as
good estimation for anaerobic capacity
• Assumption:
– Mechanical efficiency identical in supra- and submaximal
exercise
– the rate of total energy release (i.e. O2 demand) increases
linearly with the exercise intensity
– O2 demand is constant during this type of supramaximal
exercise
• Leveling off with exercise duration
– Increased with duration of exhaustive exercise until level
off
• Independent of maximal oxygen uptake (VO2max)
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20. Procedures
• VO2 – power output relationship
– Originally 10 stages at 10 min per stage
– Modified to fewer stages at 40-70% VO2max with 4
min per stage
• Duration of performance test
– Long enough to allow max anaerobic energy release
– Short enough to minimize aerobic energy production
– Constant power output 115-130% peak VO2
– Or ‘all-out’ for a specific duration or distance
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21. Oxygen stores of body
• In transition from rest to exercise, mouth VO2
underestimate tissue VO2
– O2 bind to hemoglobin and myoglobin
– O2 dissolved in body fluids
– O2 in lungs
• Estimated 9% oxygen deficit
• Should be subtracted from absolute MAOD
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22. Maximal accumulated oxygen deficit
(MAOD)
Medbo JI, 1988
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23. Accumulated oxygen deficit vs
duration of supramaximal exercise
Medbo JI, 1988
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24. Relative accumulated oxygen deficit
Medbo JI, 1988
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25. MAOD range
• 38 ml/kg in middle distance trained athletes, to
100 ml/kg in sprint trained athletes
– 60 kg: 2.3 L O2eq – 6 L O2eq
• MAOD unaffected by inspired O2 concentration
– Independent of aerobic metabolism
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27. Oxygen Deficit and Debt During Light-
Moderate and Heavy Exercise
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28. Recovery From Exercise: Metabolic
Responses
• Oxygen debt
– Elevated VO2 for several minutes immediately following
exercise
– Excess post-exercise oxygen consumption (EPOC)
• “Fast” portion of O2 debt
– Resynthesis of stored PC
– Replacing muscle and blood O2 stores
• “Slow” portion of O2 debt
– Elevated body temperature and catecholamines
– Conversion of lactic acid to glucose (gluconeogenesis)
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29. Ways to Examine These Energy
Systems
• Vertical Jump
• Margaria Kalamen
• Wingate

30. Vertical Jump
• Variables
– Mass of Subject
– Height of Subject
– Height of Jump
• Procedure
– 3 Trials
– No stepping into the jump
– Using arms tends to help
• Calculations
– Absolute Anaerobic Power
(Mean & Average)
– Absolute & Relative Peak
Anaerobic Power

31. Margaria Kalamen
• Variables
– Mass of Subject
– Height of Stairs
– Time between Stairs
• Procedure
– Run up six stairs two at
a time
– Start time on the 2nd
step end on the 6th
• Calculations
– Absolute & Relative
Anaerobic Power

32. Wingate
• Variables
– Mass of Subject
– Mass of Load
– Number of Pedal
Revolutions in 5 s Periods
for 30 s
• Procedure
– Subject Pedals as fast as
possible with no load for ~
5-10s
– Subject Pedals as fast as
possible for 30 s with load
• Calculations
– Peak Anaerobic Power
(absolute and relative)
– Fatigue Index
– Total Work

33. Success of Measurements in Studying
the Anaerobic Systems
• All tests are measures of performance
• Variations in these particular tests may have a
lot to do with muscular attributes that are not
related to energy production
• Variables that have the same name are
measures of the same concepts, but not the
same actual values

34. Problems with Performance Measures
• Daily variance
• Motivation
• Learning effect
• Not a direct measurement of physiological
variables
• Relationships to physiological variables (and
other performance tests) must be determined
and the accuracy of prediction can then be
found

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Conclusion
• Anaerobic energy system = energy system within the body
that does not require the use of oxygen
• There are two systems = ATP-PC system (lasts from 8-10
seconds) & LACTIC ACID system (operates from 15-60
seconds)
• Excess Postexercise Oxygen Consumption (Oxygen debt) =
the elevated levels of oxygen consumption during the initial
minutes of recovery, which exceed the oxygen usually
required at rest.