ENERGY FOR EXERCISE BS263

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ENERGY FOR EXERCISE BS263

• LECTURE 3. Capacity of the Energy (Power)
  systems.
• AIMS.
•         To review the contribution to energy
  production of the different energy (power)
  systems during exercise of different intensities.
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• LEARNING OBJECTIVES.
• After this section of the course you should be
  able to do the following.
• 1.      Explain the relative contributions of the
  different energy systems to exercise of different
  intensities and duration.

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BACKGROUND READING.

• McArdle, W.D., Katch, F.I. and Katch, V.L.
  (2006). Exercise Physiology. (6th Edition)
  Lippincott Williams and Wilkins. Baltimore.
• Maughan, R. and Gleeson, M. (2004) The
  Biochemical basis of Sports Performance. Chapters
  1,3,4, 5, Oxford University Press
• Gastin PB (2001), Energy system interaction and
  relative contribution during maximal exercise.
  Sports Medicine 31, (10), 725-741
• Read this paper PDF in CMR

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Capacity of the power systems.

• Anaerobic alactic.
• What is the capacity of this system?
• 5 mM ATP (MW 507), 15 mM CP (MW 211)
• What would this be as mass in a 60 kg female?
• Would last about 7 s (if max and exclusive).
• When is it engaged?
• Maximal intensity brief intermittent.
• Temporal buffer.
• How long to regenerate?
• Half time about 1 min. at rest
• (McCann et al., 1995)

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Capacity of the power systems.

• Anaerobic lactic.
• What is the capacity of this system?
• 90 s (proton accumulation) 6 min (glycogen
  depletion)
• When is it engaged?
• High intensity, short duration
• Energy buffer during fast component of O2
  kinetics.
• Why does lactate accumulate?
• Rate of production (of pyruvate) exceeds rate of
  mitochondrial uptake and lactate shuttle
• Blood lactate profiles. (Fig 7.2)

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Capacity of the power systems.

• Aerobic.
• What is the capacity of this system?
  (Carbohydrate? Fat?).
• Aerobic systems release more of the potential
  energy that is present in macronutrients.
• Glycogen gt90 min (500 g, 2000 kcal).
• Lipid several days. 7 kg fat x 9 kcal.g-1
  gt63,000 kcal gt20 marathons or gt30 days at rest.
• When is it engaged?
• The long term power system. Reflected by O2
  kinetics. Maximal rate of energy production
  (VO2max) limited by delivery (supply side
  central limitations) and consumption (peripheral
  limitations).
• See Fig 7.3.

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Power system spectrum of exercise.

• How does the spectrum of energy systems engaged
  vary with intensity and duration of exercise?
• Different activities (intensity/duration) engage
  the power systems in characteristic proportions
  at different stages in the activity.

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Relative contribution of the energy systems in
brief maximal exercise.
10 s
30 s
90 sec
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Absolute contribution of the energy systems in
brief maximal exercise.
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Relative contribution of anaerobic and aerobic
energy systems in maximal exercise of different
durations.
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Implications of the energy spectrum of exercise
for training.

• Why is it helpful for athletes and their coaches
  to be aware of the energy spectrum of their
  event?
• Specificity of training.
• Are the energy systems cross-trainable? (Tanaka
  and Swensen 1998)
• To some extent.
• What kind of training is appropriate for the
  anaerobic alactic system?
• High intensity intermittent brief (lt10 s) and
  brief recovery.
• What parameters might be susceptible to this kind
  of training?
• Fig 21.3, Table 21.4
• What kind of training is appropriate for the
  anaerobic lactic system?
• High intensity, longer efforts (lt2 min) and
  recovery.
• What parameters might be susceptible to this kind
  of training?

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Potential for enhancement of capacity of
components of anaerobic power systems by
appropriate training.
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Implications of the energy spectrum of exercise
for training.

• What kind of training is appropriate for the
  aerobic system?
• LSD and threshold training.
• What parameters might be susceptible to this kind
  of training?
• VO2max VO2max at LT.
• Table 21.3.
• Other than training the power systems, what are
  the other expected outcomes of training?
• Central and peripheral adaptations.
• Patterns of motor recruitment.
• Skills enhancement.