Energy For Muscular Activity

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Energy for Muscular Activity

• Chapter 5

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Learning Objectives

• To develop an awareness of the basic chemical
  process that the body uses to produce energy in
  the muscles
• To develop an understanding of the bodys three
  main energy systems
• To introduce the effect of training and exercise
  on the energy systems

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The Chemistry of Energy Production

• Energy in the human body is derived from the
  breakdown of complex nutrients like
  carbohydrates, fats, and proteins.
• The end result of this breakdown is production of
  the adenosine triphosphate (ATP) molecule.
• ATP provides energy necessary for body functions

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ATP Cycle Overview

• a) ATP breakdown
• b) Phosphorylation
• c) ATP resynthesis

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• a) ATP breakdown (ATP turnover)

• 1. Hydrolysis of the unstable phosphate groups of
• ATP molecule by H2O

• 3. Energy is released (38-42 kJ, or 9-10kcal/ mol
  ATP)

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• b) Phosphorylation

Energy for muscle contraction
1. Energy released by ATP turnover can be used
by body when a free P group is transferred
to another molecule (phosphorylation)
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• c) ATP resynthesis

• Initial stores of ATP in the muscles are used up
• very quickly and ATP must be regenerated

2. ATP is formed by recombination of ADP and P
3. Regeneration of ATP requires energy (from
breakdown of food molecules)
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The Energy Systems
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The Roles of the Three Energy Systems in
Competitive Sport
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1. The High Energy Phosphate System
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The High Energy Phosphate System Overview
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High Energy Phosphate System
ADP Pi ? ATP
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Training the High Energy Phosphate System

• a) Interval training
• - 20 increase in CP (creatine phosphate)
  stores
• - no change in ATP stores
• - increase in ATPase function (ATP -gt ADPP)
• - increase in CPK (creatine phosphokinase)
  function (CPK breaks down CP molecule and
  allows ATP resynthesis)
• b) Sprint training
• - increase in CP stores up to 40
• - 100 increase in resting ATP stores