Summary Bioenergetics of Exercise and training

BIOENERGETICS OF
EXERCISE AND TRAINING
Chapter 3

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Contents
Essential terminology............................................................................................................................................................2
Biological Energy Systems.....................................................................................................................................................5
Terminology:..................................................................................................................................................................... 5
Phosphagen System..........................................................................................................................................................5
ATP stores:.....................................................................................................................................................................5
Control of the Phosphagen System...............................................................................................................................5
Glycolysis........................................................................................................................................................................... 6
Glycolysis and the Formation of Lactate........................................................................................................................8
Glycolysis Leading to the Krebs Cycle............................................................................................................................9
Energy Yield of Glycolysis..............................................................................................................................................9
Control of Glycolysis....................................................................................................................................................10
Lactate Threshold and Onset of Blood Lactate Accumulation.....................................................................................10
The Oxidative (Aerobic) System.......................................................................................................................................11
Glucose and Glycogen Oxidation.................................................................................................................................11
Fat Oxidation...............................................................................................................................................................14
Protein Oxidation........................................................................................................................................................14
Control of the Oxidative (Aerobic) System..................................................................................................................14
Energy Production and Capacity......................................................................................................................................16
Substrate Depletion and repletion......................................................................................................................................17
Phosphagens................................................................................................................................................................... 17
Glycogen.......................................................................................................................................................................... 17
Glycogen cont’d...............................................................................................................................................................18
Bioenergetic Limiting Factors in Exercise Performance.......................................................................................................19
Oxygen Uptake and the Aerobic and Anaerobic Contributions to Exercise.........................................................................20
Metabolic Specificity of Training.........................................................................................................................................23
Interval Training..............................................................................................................................................................23
High-Intensity Interval Training.......................................................................................................................................24
Combination Training......................................................................................................................................................25

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Essential terminology
 Bioenergetics/ the flow of energy in a biological system concerns:
o Primarily the conversion of macronutrients(carbohydrates, protein and fats), which contain chemical
energy, into useable forms of energy
 Catabolism:
o Breakdown of large molecules into smaller molecules
o Associated with the release of energy
 Anabolism
o Synthesis of larger molecules from smaller molecules
o Can be accomplished using energy released from catabolic reactions
 Exergonic reactions
o Energy-releasing reactions, generally catabolic
 Endergonic reactions
o Require energy and include anabolic processes and the contraction of muscle
 Metabolism:
o Total of all the catabolic/exergonic and anabolic/endergonic reactions in a biological system
 Adenosine triphosphate (ATP):
o Energy derived from catabolic/exergonic reactions is used to derive anabolic/endergonic reactions
through this molecule
o Allows the transfer of energy from exergonic to endergonic reactions
o Without adequate supply of ATP, muscular growth would not be possible
o Comprised of adenosine and three phosphate groups
o Adenosine = combination of adenine and ribose
 Hydrolysis:
o Breakdown of one molecule of ATP to yield energy
o Requires one molecule of water
o Catalyzed by presence of enzyme : adenosine triphosphatase (ATPase)
o Myosin ATPase = enzyme that catalyzes ATP hydrolysis for crossbridge recycling
 Other specific enzymes hydrolyze ATP at other locations
o Calcium ATPase = pumping calcium into sarcoplasmic reticulum
o Sodium-potassium ATPase = maintaining sarcolemma concentration gradient after depolarization
 ATP hydrolysis:



 ATP + H2OATPase ADP + Pi + H+ + energy (1)
 ADP= Adenosine diphosphate
 Pi= inorganic phosphate
 H+= hydrogen ion
 Further hydrolysis of ADP= cleaves second phosphate yielding adenosine monophosphate (AMP)
 Energy released from hydrolysis of ATP and ADP= biological work