AIS Chap 5
Anaerobic capacity
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Anaerobic power and
anaerobic capacity
• Anaerobic power 無氧動力: 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 無氧能力: 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
2
Measure anaerobic ATP production
• Muscle biopsy 肌肉穿刺: Changes in muscle
metabolites
• Blood lactate after supramaximal exercise
• Oxygen debt 氧債 after supramaximal exercise
• Total work or mean power output during shortduration 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
3
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
4
The Oxygen Deficit
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Differences in VO2 Between Trained
and Untrained Subjects
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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
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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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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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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
10
Maximal accumulated oxygen deficit
(MAOD)
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Medbo JI, 1988
Accumulated oxygen deficit vs
duration of supramaximal exercise
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Medbo JI, 1988
Relative accumulated oxygen deficit
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Medbo JI, 1988
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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15
Oxygen Deficit and Debt During LightModerate and Heavy Exercise
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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)醣質新
生
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