Biochemistry for Sport and Exercise Metabolism

Don MacLaren is currently Professor of Sports Nutrition at Liverpool. He has taught physiology, biochemistry and nutrition at JMU for a number of years. He is Chair of the BASES Sports Nutrition interest group and is a member of the Sport & Exercise Nutrition working party under the auspices of the Nutrition Society.James Morton is a lecturer in sports metabolism. He has twice received 'Young Investigator Awards' from the European College of Sports Science, in 2006 and 2008.

• Preface xi One: Basic Muscle Physiology and Energetics 11 Energy sources for muscular activity 31.1 Adenosine triphosphate: the energy currency 31.2 Energy continuum 41.3 Energy supply for muscle contraction 41.4 Energy systems and running speed 71.5 Why can't a marathon be sprinted? 71.6 Energy sources and muscle 81.7 Can muscle use protein for energy? 91.8 Key points 102 Skeletal muscle structure and function 112.1 Skeletal muscle structure 122.1.1 Gross anatomical structure 122.1.2 The muscle fibre 132.2 Muscle contraction 182.2.1 Propagation of the action potential 182.2.2 Excitation-contraction coupling 182.2.3 The sliding filament mechanism 202.3 Muscle fibre types 212.3.1 General classification of muscle fibres 212.3.2 Muscle fibre distribution 232.3.3 Muscle fibre recruitment 242.4 Muscles in action 262.4.1 Types of muscle contraction 262.4.2 The twitch contraction 262.4.3 The length-tension relationship 272.4.4 Tetanus contractions 272.4.5 Force-velocity relationship 282.4.6 Muscle fatigue 292.5 Key points 293 Biochemical concepts 313.1 Organization of matter 323.1.1 Matter and elements 323.1.2 Atoms and atomic structure 323.1.3 Atomic number and mass number 343.1.4 Atomic mass 343.1.5 Ions, molecules, compounds and macronutrients 343.2 Chemical bonding 353.2.1 Ionic bonds 363.2.2 Covalent bonds 363.2.3 Molecular formulae and structures 383.2.4 Functional groups 393.3 Chemical reactions, ATP and energy 403.3.1 Energy 403.3.2 ATP 413.3.3 Units of energy 423.3.4 Types of chemical reactions 433.4 Water 453.4.1 General functions of water 453.4.2 Water as a solvent 463.5 Solutions and concentrations 463.6 Acid-base balance 473.6.1 Acids, bases and salts 473.6.2 pH Scale 483.6.3 Buffers 493.7 Cell structure 493.7.1 The plasma membrane 503.7.2 The nucleus 513.7.3 Cytoplasm and organelles 513.8 Key points 53Two: Fundamentals of Sport and Exercise Biochemistry 554 Proteins 574.1 Protein function 584.1.1 General protein function 594.2 Amino acids 624.2.1 Amino acid structure 624.3 Protein structure 624.3.1 Primary structure 624.3.2 Secondary structure 654.3.3 Tertiary structure 654.3.4 Quaternary structure 654.4 Proteins as enzymes 674.4.1 Mechanisms of enzyme action 674.4.2 Factors affecting rates of enzymatic reactions 684.4.3 Coenzymes and cofactors 704.4.4 Classification of enzymes 704.4.5 Regulation of enzyme activity 724.5 Protein turnover 734.5.1 Overview of protein turnover 734.5.2 DNA structure 734.5.3 Transcription 744.5.4 The genetic code 744.5.5 Translation 764.6 Amino acid metabolism 784.6.1 Free amino acid pool 794.6.2 Transamination 794.6.3 Deamination 804.6.4 Branched chain amino acids 824.6.5 Glucose-alanine cycle 824.6.6 Glutamine 824.6.7 The urea cycle 854.7 Key points 855 Carbohydrates 875.1 Relevance of carbohydrates for sport and exercise 885.2 Types and structure of carbohydrates 905.2.1 Monosaccharides 905.2.2 Disaccharides and polysaccharides 915.3 Metabolism of carbohydrates 925.3.1 Glycogenolysis 935.3.2 Glycolysis 955.3.3 Lactate metabolism 985.3.4 The 'link' reaction; production of acetyl-CoA 985.3.5 The TCA (or Krebs) cycle 985.3.6 Electron transport chain 985.3.7 Oxidative phosphorylation 1005.3.8 Calculation of ATP generated in glucose oxidation 1015.3.9 Overview of glucose oxidation 1025.3.10 Fructose metabolism 1025.3.11 Gluconeogenesis 1025.3.12 Glycogenesis 1035.4 Key points 1076 Lipids 1096.1 Relevance of lipids for sport and exercise 1106.2 Structure of lipids 1126.2.1 Classification of lipids 1126.2.2 Compound lipids 1156.2.3 Derived lipids 1156.3 Metabolism of lipids 1156.3.1 Lipolysis 1156.3.2 ß-oxidation 1186.3.3 Ketone body formation 1196.3.4 Formation of fatty acids 1196.3.5 Triglyceride synthesis 1226.4 Key points 124Three: Metabolic Regulation in Sport and Exercise 1277 Principles of metabolic regulation 1297.1 How are catabolic and anabolic reactions controlled? 1307.2 Hormones 1307.3 Peptide hormones, neurotransmitters and regulation 1337.3.1 Adrenaline activation of glycogenolysis 1347.3.2 Adrenaline activation of lipolysis 1357.3.3 Insulin activation of glycogen synthase 1357.3.4 Insulin inhibition of lipolysis 1377.3.5 Insulin stimulation of protein synthesis 1377.4 Steroid hormones and regulation 1387.5 Allosteric effectors 1407.5.1 Regulation of glycogen phosphorylase 1407.5.2 Regulation of PFK 1407.5.3 Regulation of PDH 1407.5.4 Regulation of CPT1 1427.5.5 AMPK as a metabolic regulator 1427.6 Key points 1448 High-intensity exercise 1458.1 Overview of energy production and metabolic regulation in high-intensity exercise 1458.1.1 Definition of high-intensity exercise 1458.1.2 Energy production during high-intensity exercise 1468.1.3 Evidence of energy sources used in HIE 1488.1.4 Metabolic regulation during high-intensity exercise 1528.2 Effects of exercise duration 1528.3 Effects of nutritional status 1538.3.1 Can nutritional ergogenic aids help HIE? 1548.4 Effects of training 1558.5 Mechanisms of fatigue 1578.5.1 Reduced ATP 1588.5.2 Reduced PCr 1598.5.3 Increased Pi 1598.5.4 Lactate and H+ 1608.6 Key points 1619 Endurance exercise 1639.1 Overview of energy production and metabolic regulation in endurance exercise 1649.1.1 Definition and models of endurance exercise 1649.1.2 Energy production in endurance exercise 1649.1.3 Overview of metabolic regulation in endurance exercise 1659.2 Effects of exercise intensity 1669.2.1 CHO metabolism 1669.2.2 Lipid metabolism 1689.3 Effects of exercise duration 1729.4 Effects of nutritional status 1749.4.1 CHO-loading and muscle glycogen availability 1749.4.2 Fat-loading strategies 1769.4.3 Pre-exercise and during-exercise CHO ingestion 1789.4.4 Pre-exercise FFA availability 1819.5 Effects of training status 1839.5.1 CHO metabolism 1839.5.2 Lipid metabolism 1849.5.3 Protein metabolism 1889.6 Mechanisms of fatigue 1899.7 Key points 19210 High-intensity intermittent exercise 19510.1 Overview of energy production in intermittent exercise 19610.1.1 Definition and models of intermittent exercise 19610.1.2 Energy systems utilized in intermittent exercise 19710.2 Metabolic regulation in intermittent exercise 19710.3 Effects of manipulating work-rest intensity and ratio 20210.4 Effects of nutritional status 20610.4.1 Muscle glycogen availability 20710.4.2 Pre-exercise CHO ingestion 20710.4.3 CHO ingestion during exercise 20910.5 Muscle adaptations to interval training 21010.6 Mechanisms of fatigue 21510.6.1 Carbohydrate availability 21610.6.2 PCr depletion 21710.6.3 Acidosis 21810.6.4 Extracellular potassium 22010.6.5 Reactive oxygen species (ROS) 22110.6.6 Pi accumulation and impaired Ca2+ release 22310.7 Key points 224References and suggested readings 227Index 241