Muscle and Exercise Physiology

Muscle and Exercise Physiology is a comprehensive reference covering muscle and exercise physiology, from basic science to advanced knowledge, including muscle power generating capabilities, muscle energetics, fatigue, aging and the cardio-respiratory system in exercise performance. Topics presented include the clinical importance of body responses to physical exercise, including its impact on oxygen species production, body immune system, lipid and carbohydrate metabolism, cardiac energetics and its functional reserves, and the health-related effects of physical activity and inactivity. Novel topics like critical power, ROS and muscle, and heart muscle physiology are explored. This book is ideal for researchers and scientists interested in muscle and exercise physiology, as well as students in the biological sciences, including medicine, human movements and sport sciences. - Contains basic and state-of-the-art knowledge on the most important issues of muscle and exercise physiology, including muscle and body adaptation to physical training, the impact of aging and physical activity/inactivity - Provides both the basic and advanced knowledge required to understand mechanisms that limit physical capacity in both untrained people and top class athletes - Covers advanced content on muscle power generating capabilities, muscle energetics, fatigue and aging Front Cover......Page 1 Muscle and Exercise Physiology......Page 4 Copyright Page......Page 5 Dedication......Page 6 Contents......Page 8 List of Contributors......Page 18 Preface......Page 22 I. Skeletal Muscle Morphology......Page 24 1.2 The Assessment of the System as a Whole......Page 26 1.2.1 Body Mass, Basal Metabolic Rate, and Total Daily Energy Expenditure......Page 27 1.2.2 Body Mass Index......Page 28 1.2.3 Body Circumferences and Skinfolds Measurements......Page 29 1.2.4 Body Surface Area......Page 30 1.2.5 Body Volume and Body Density......Page 31 1.3.1.2 Total Body Potassium......Page 32 1.3.2.1 Total Body Water......Page 33 1.3.2.4 Total Body Mineral......Page 35 1.3.3.1 Extracelullar Fluid......Page 36 1.3.3.3 Body Cell Mass......Page 37 1.3.4 Body Composition at the Tissue–Organ Level......Page 38 1.3.4.2 Skeletal Muscle Tissue......Page 39 1.4 Basics of Body Compartmentalization......Page 42 1.4.1 Two-Compartment Model of Body Composition......Page 43 References......Page 44 2.2 Muscle Fibers, Basic Morphological and Physiological Units......Page 50 2.2.1 Microscopic Structure of Muscle Fibers......Page 51 2.2.2.1 A Bands......Page 53 2.2.2.3 Z line......Page 54 2.4 The Capillary Network of the Muscle Fibers......Page 55 2.5 Sarcoplasmic Reticulum......Page 58 2.6 Proteins of the Sarcoplasmic Reticulum Membranes......Page 59 References......Page 60 3.1 Introduction......Page 62 3.2 The Motor—Myosin......Page 63 3.4.1 The Cross-Bridge Cycle......Page 65 3.5 The Sensor......Page 67 3.7.1 Force-Frequency Relationship and Recruitment......Page 69 3.8 Relaxation......Page 70 References......Page 71 4.2.1 The Motor Unit......Page 74 4.2.3 Classification of Motor Units......Page 76 4.2.4 Variability in the Contractile Properties of Motor Units......Page 77 4.3.1 Location, Morphology, and Innervation......Page 80 4.3.2 Motoneuron Excitability—Diversity of Motoneurons of S, FR, and FF Motor Units......Page 83 4.3.3 Rhythmic Firing of Motoneurons—Bistability and Adaptation......Page 85 4.3.4 Synaptic Input to Motoneurons......Page 87 4.4 Recruitment of Motor Units......Page 88 4.4.1 Henneman’s Size Principle......Page 89 4.5.1 The Force–Frequency Relationship......Page 90 4.5.2 Force Modulation by the Pattern of Motoneuronal Firing......Page 95 4.6 Motor Unit Action Potentials......Page 97 4.7 Differences in Motor Unit Properties Between Muscles......Page 99 4.8 Interspecies Differences in Motor Units......Page 100 4.10 Plasticity of Motor Units......Page 102 4.10.1 Plasticity of Motor Unit Contractile Properties......Page 103 4.10.2 Plasticity of Motoneurons......Page 104 4.11.1 Muscle Spindles......Page 106 4.11.2 Tendon Organs......Page 108 4.12.1 Electrophysiological Investigation of Functionally Isolated Motor Units......Page 109 References......Page 110 II. Muscle Energetics and Its Performance......Page 116 5.2.3 Metabolic Regulation......Page 118 5.3 Noninvasive Access to Skeletal Muscle Metabolism......Page 119 5.4.2 13C MRS Measurement of TCA Cycle Flux......Page 120 5.4.3.1 ATP Supply and Demand......Page 121 5.4.3.3 Feedback Regulation and Its Limits......Page 122 5.5 Interpreting 31P MRS Data: Measurements in Muscle at Rest......Page 123 5.7 Interpreting 31P MRS Data: Exercise Responses......Page 124 5.7.3 “Oxidative” Exercise, Where Glycolytic ATP Synthesis Can Be Ignored......Page 125 5.7.4 Recovery From Exercise: Studying Mitochondrial Function......Page 126 5.7.5 Recovery From Exercise: Studying Proton Efflux......Page 127 5.7.6 High Intensity Exercise: Glycolytic and Oxidative ATP Synthesis......Page 128 5.8.3 Combining NIRS and 31P MRS......Page 129 References......Page 130 6.2.1 Biochemical Changes in Response to Contractile Activity......Page 134 6.3 Thermodynamics of Muscle Contraction......Page 135 6.3.2.1 Initial Enthalpy Output From PCr Breakdown......Page 136 6.3.2.2 Recovery Enthalpy Output From Substrate Oxidation......Page 137 6.4.1.1 Initial Mechanical Efficiency......Page 138 6.4.1.2 Efficiency Depends on Shortening Velocity or Force Opposing Shortening......Page 139 6.4.1.4 Problems With Expressing Efficiency in Terms of Initial Enthalpy Output......Page 140 6.4.1.6 Effect of Fiber Type on Cross-Bridge Thermodynamic Efficiency......Page 141 6.4.1.8 What Limits Cross-Bridge Thermodynamic Efficiency?......Page 142 6.4.2.1 Estimates From ηCB and Empirical Recovery/Initial Enthalpy Ratio......Page 143 6.4.2.2 Direct Measurements of Overall Efficiency......Page 144 6.5.1 Data From Isolated Human Muscle Fibers......Page 145 6.5.2.3 Estimating Cross-Bridge Thermodynamic Efficiency for Human Muscle......Page 146 6.6 Conclusion......Page 147 References......Page 148 Appendix 6.1......Page 149 Appendix 6.2......Page 150 7.2 Muscle Activation......Page 152 7.2.2 Muscle Fiber Types......Page 153 7.2.3 Contractile Properties......Page 155 7.2.4 Motor Unit Activation......Page 156 7.3.1 Sarcomere......Page 158 7.3.2 Muscle Fiber Length......Page 159 7.3.3 Muscle Fiber Anatomy......Page 160 7.4 Muscle Function......Page 161 7.4.1.1 Assessment......Page 162 7.4.1.2 Voluntary Activation......Page 164 7.4.1.3 Stretch-Shorten Cycle......Page 165 7.4.1.4 Training Adaptations......Page 167 7.4.2.2 Voluntary Activation......Page 168 7.4.2.3 Speed-Related Adaptations......Page 170 7.4.3 Fatigability......Page 171 7.4.3.1 Fatigue Taxonomy......Page 172 7.4.3.2 Task Dependency......Page 173 References......Page 176 8.2 Historical Bases for the Critical Power Concept......Page 182 8.3 The Critical Power Concept: Mechanistic Bases......Page 186 8.3.1 Inspiratory Hyperoxia......Page 188 8.3.3 Inspiratory Hypoxia: Chronic......Page 189 8.3.4 Impact of Duty Cycle on Critical Power......Page 190 8.3.7 All-Out Maximal Exercise......Page 191 8.4 Application of the Critical Power Concept to All-Out Exercise (Whole Body, Limb, Muscle Group, Isolated Muscle)......Page 192 8.5.1.1 Training......Page 194 8.5.1.2 Competition......Page 195 8.5.3 Why Measure Critical Power and Wʹ as a Guide for Assessing Exercise Tolerance?......Page 196 8.7 Challenges to the Critical Power Concept......Page 198 8.8 Conclusions......Page 199 References......Page 200 9.1 Introduction......Page 206 9.3 Walking and Running......Page 207 9.3.1.2 Locomotion Pathologies......Page 211 9.3.1.3 Body Mass and Age......Page 212 9.3.2 Accelerated/Decelerated Running......Page 214 9.5.1 Mechanical Work and Energy Cost......Page 216 9.5.2 The Efficiency of Cycling......Page 218 9.5.4.1 On Size and Shape......Page 219 9.5.5 Altitude and Performance......Page 220 9.5.5.1 One-Hour Record for Unaccompanied Cycling......Page 222 9.5.6 On Sloping Grounds......Page 223 9.5.6.1 Metabolic Power and Body Mass......Page 224 9.6 Cross-Country Skiing......Page 225 9.7 Locomotion in Water......Page 226 9.7.1.1 “Good” and “Bad” Swimmers and Different Styles......Page 227 9.7.1.2 Of Men and Women......Page 228 9.7.2 The Biomechanics of Swimming: Hydrodynamic Drag and Efficiency......Page 229 9.7.3.1 Energy Cost......Page 231 9.7.3.2 Hydrodynamic Resistance and Efficiency......Page 232 References......Page 234 III. Muscle Metabolism and Exercise Physiology......Page 238 10.1.1 Introduction to Exercise Bioenergetics......Page 240 10.2.1 Exercise Intensity Domains......Page 242 10.2.2 Ramp-Incremental Exercise......Page 243 10.2.2.2 The “V-Slope” Relationship......Page 244 10.2.2.3 Maximum Oxygen Uptake (V̇O2max)......Page 247 10.2.2.4 Determinants of Maximum Oxygen Uptake (V̇O2max)......Page 248 10.2.3 Constant Power Exercise and V̇O2 Kinetics......Page 249 10.2.3.1 Moderate-Intensity V̇O2p Kinetics......Page 250 10.2.3.2 Heavy, Very-Heavy, and Severe-Intensity V̇O2p Kinetics......Page 251 10.3.1 Oxygen Stores......Page 253 10.3.3 Flow-Weighted Venous Admixture......Page 254 10.4.1 Evidence From Computer Simulation......Page 255 10.4.2 Evidence From Direct Measurement......Page 256 10.4.3 Kinetic Control of Muscle V̇O2......Page 257 10.4.3.1 Feedback Control by Intramuscular Phosphates......Page 258 10.4.3.3 Limitation by Skeletal Muscle Oxygenation......Page 260 10.4.3.4 Role of Oxidative Enzyme Activation......Page 262 10.5.2 Chronic Heart Failure......Page 263 10.5.3 Chronic Obstructive Pulmonary Disease......Page 264 References......Page 265 11.1 Introduction......Page 274 11.2 Overview of Carbohydrate Storage......Page 275 11.3 Regulation of Carbohydrate Metabolism......Page 276 11.3.1 Effects of Exercise Intensity and Duration......Page 277 11.3.2 Effects of Substrate Availability......Page 279 11.3.3 Effects of Training Status......Page 280 11.4.1 Muscle Glycogen and Carbohydrate Loading......Page 281 11.4.3 Carbohydrate Feeding During exercise......Page 282 11.5.1 Overview of Molecular Regulation of Training Adaptations......Page 283 11.5.2 Fasted Training......Page 284 11.5.5 Sleep-Low/Train-Low Models......Page 285 11.5.6 High-Fat Feeding......Page 286 11.5.7 Muscle Glycogen Threshold......Page 287 11.6 Conclusions......Page 289 References......Page 290 12.1.1 Trafficking of LCFA Across Sarcolemma......Page 294 12.1.3 Mechanisms of FA Transporters Translocation......Page 296 12.2.1 Glycerophospholipids......Page 297 12.2.3 Triacylglycerol lipases......Page 299 12.3.1 Metabolism of Sphingolipids......Page 300 12.3.4 Sphingosine-1-Phosphate and Skeletal Muscle Regeneration......Page 301 12.4.1 Triacylglycerols......Page 302 12.5 Conclusions......Page 303 References......Page 304 13.2 History: Myokines......Page 308 13.4.1.2 Exercise and Systemic Levels of Interleukin-6......Page 310 13.4.1.3 Interleukin-6 is an Energy Sensor......Page 312 13.4.1.4 Interleukin-6: A Role in Glucose and Lipid Metabolism......Page 313 13.4.3 Brain-Derived Neurotrophic Factor......Page 314 13.4.5 Interleukin-8......Page 316 13.4.6 Interleukin-15......Page 317 13.4.7 Leukemia Inhibitory Factor......Page 318 13.4.8 Irisin......Page 319 13.5.2 Follistatin-Like 1......Page 320 13.7 Myokine Screening......Page 321 References......Page 323 14.2 Differentiation of Fiber Types and Biogenesis of Mitochondria......Page 332 14.3 Muscle Contraction and Reactive Oxygen and Nitrogen Species......Page 333 14.4 RONS-Associated Oxidative Damage and Repair......Page 335 14.5 Conclusions......Page 336 References......Page 337 15.2.2 Effects With Strenuous Training/in Athletes......Page 340 15.3 Etiology of Upper Respiratory Illness......Page 342 15.4.1 Moderate Exercise......Page 344 15.4.2.1.1 Leukocyte Count Changes and Acute Exercise......Page 345 15.4.2.1.2 Innate Immune Cell Function and Acute Exercise......Page 346 15.4.2.1.3 Acquired Immune Cell Function and Acute Exercise......Page 348 15.4.2.1.4 Mucosal Immunity and Acute Exercise......Page 350 15.4.3 Exercise Training and Immune Function......Page 354 15.4.3.1 In Vitro and Ex Vivo Markers: Moderate Exercise......Page 355 15.4.3.2.1 Strenuous or Intensive Exercise......Page 356 15.5 Conclusions......Page 357 References......Page 358 IV. Body Adaptation to Exercise......Page 368 16.2.2 Fast- and Slow-Type Muscle: Connecting a Functional Link of the Muscle Fiber to Its Motor Neuron......Page 370 16.2.3 The Contributions of Archibald Vivian Hill to Fundamental Muscle Contraction Processes......Page 373 16.3.2 The Early Science of Muscle Plasticity: Adaptive Responses of Muscle Fibers to Simulated Physical Activity......Page 374 16.3.3 Early Studies on Exercise-Induced Adaptations in Skeletal Muscle......Page 375 16.4.2.1 Animal Studies......Page 376 16.4.3.1 Animal Studies......Page 377 16.4.4 Can Fast-Type Fibers Become Converted Into Slow-Type Fibers by Physical Activity Paradigms?......Page 378 16.5.1 Advancing Biotechnologies and Identification of the Myosin Heavy Chain Gene Family......Page 379 16.5.3 Functional Properties of the Myosin Heavy Chain Isoforms......Page 381 16.5.4.3 Resistance Exercise as a Countermeasure to Limb Unloading......Page 382 16.5.5 Single-Fiber Myosin Heavy Chain Polymorphism: How Many Patterns and the Role of Loading Conditions......Page 383 16.6.2.1 Supporting Evidence......Page 384 16.6.3.1 Protein Synthesis Alterations......Page 386 16.6.4 Mechanisms of Mitochondrial Biosynthesis Regulation Muscle Performance......Page 387 16.6.5.1 Approaches in Studying Gene Transcription in Response to Altered Activity Paradigms......Page 388 16.6.5.3 Calcineurin Signaling and Slow Myosin Heavy Chain Gene During Altered Activity Patterns......Page 389 16.6.6 Epigenetics and Muscle Gene Regulation in Response Unloading and to Exercise......Page 390 16.6.7 Role of Noncoding Antisense RNA During Altered Loading States......Page 391 16.6.9 Mechanisms of Mitochondrial Biogenesis and Degradation......Page 392 16.7 Conclusions......Page 393 References......Page 394 17.1 Introduction......Page 402 17.2 Anatomy and Functional Organization of the Skeletal Muscle Vasculature......Page 403 17.4 Interaction Between Metabolic and Sympathetic Control of Muscle Blood Flow......Page 404 17.5 Muscle Blood Flow Heterogeneity......Page 405 17.6 Impact of Exercise Training on Skeletal Muscle Blood Flow......Page 406 17.8 Impact of Exercise Training on Skeletal Muscle Capillarization......Page 408 17.9 Effects of Exercise Training on Skeletal Muscle Vascular Control......Page 409 References......Page 410 18.1 Introduction......Page 414 18.2 The Oxygen Uptake–Power Output Relationship......Page 416 18.3.1 Overall V̇O2 Kinetics......Page 419 18.3.2 Three Phases of Pulmonary V̇O2 Responses......Page 421 18.4.1 Primary Component of the Pulmonary V̇O2 On-Kinetics......Page 422 18.4.2 The Slow Component of Pulmonary V̇O2 On-Kinetics......Page 423 18.6.1 Oxygen Deficit......Page 424 18.6.2 The Rate of Adjustment of the V̇O2 On-Kinetics and the Size of the O2 Deficit: What Do They Tell Us?......Page 425 18.6.3 Oxygen Debt or the Excess Postexercise Oxygen Consumption......Page 426 18.6.5 V̇O2 Off-Kinetics: Other Approaches......Page 428 18.7.2 The Slow Component of the V̇O2 On-Kinetics......Page 429 18.8.1 Endurance Training and Muscle Metabolic Stability......Page 431 18.8.2 Endurance Training and the V̇O2 On-Kinetics......Page 432 18.8.3.1 Intensification of Mitochondrial Biogenesis......Page 433 18.8.3.2 Oxygen Delivery......Page 434 18.8.3.4 Intensification of Parallel Activation......Page 435 18.8.4 The Effect of Physical Training on the Slow Component of the Pulmonary V̇O2 On-Kinetics......Page 436 References......Page 438 19.2 Muscle Ageing and Daily Life Activities......Page 446 19.4.1 Age-Related Loss of Muscle Mass......Page 447 19.4.6 Neural Control......Page 448 19.6 Muscle Wasting and Function: Causes and Mechanisms......Page 449 19.6.1.2 Denervation–Reinnervation......Page 450 19.6.2 Mechanisms of Muscle Weakness......Page 451 References......Page 452 20.1 Introduction......Page 456 20.2.1.1 Short Excursion I; Basics: Bone Physiology......Page 458 20.2.1.2 Relevance of Bone Strengthening Versus Fall-, Fall-Impact Reduction......Page 459 20.2.3 Step Three: Defining the Most Relevant Primary Aims(s) of the Exercise Protocol......Page 460 20.2.4.1.1 Evidence for Exercise-Induced Fall Reduction......Page 461 20.2.4.1.3 Exercise Effects on Fall Impact......Page 462 20.2.4.2.2 Evidence for Exercise Effects on Bone Mineral Density......Page 463 20.2.4.3.2 Osteoanabolic Effect of Different Sports......Page 464 20.2.4.4.2 Strain Magnitude......Page 465 20.2.4.4.3 Strain rate......Page 466 20.2.4.4.4 Cycle Number, Repetitions......Page 467 20.2.4.4.7 Strain Density......Page 468 20.2.4.5 Considerations of Basis Principals of Exercise Training......Page 469 20.2.5 Step Five: Validation of Training Aims; Reappraisal......Page 470 References......Page 471 V. Heart Muscle and Exercise......Page 480 21.2 Morphology of the Cardiac Myocyte and its Contractile Machinery......Page 482 21.3 The Lateral Plasma Membrane and Transverse Tubules......Page 483 21.5 Intercellular Junctions Linking Cardiomyocytes......Page 484 21.6 Intermediate Filaments, Costameres, and the Plasma Membrane Skeleton......Page 487 21.8 Conclusions......Page 488 References......Page 489 22.2.1 Myocardial O2 Demand......Page 490 22.2.2.2 Oxygen Carrying Capacity of Arterial Blood......Page 491 22.2.2.3 Myocardial O2 Extraction......Page 492 22.2.3.1 Effective Perfusion Pressure......Page 493 22.2.4.1 Systolic Compression of Intramyocardial Vessels......Page 495 22.2.4.2 Subendocardial/Subepicardial Blood Flow Ratio......Page 496 22.2.4.3 Influence of Vasomotor Tone on the Transmural Distribution of Myocardial Blood Flow......Page 497 22.2.5 Coronary Blood Flow to the Right Ventricle......Page 498 22.2.6.1 Autonomic Nervous System......Page 499 22.2.6.3 Endothelium-Derived Vasoactive Factors......Page 503 22.2.6.4 Metabolic Messengers......Page 506 22.2.6.5 End-Effectors: K+-Channels......Page 507 22.2.6.6 Integration of Coronary Vasodilator Mechanisms During Exercise......Page 509 22.2.7 Epicardial Coronary Arteries......Page 510 22.2.8 The Coronary Circulation in Acute Exercise: Summary and Conclusions......Page 511 22.3.1 Structural Vascular Adaptations in the Heart......Page 512 22.3.2.2 Exercise Training and Vascular Control in the Coronary Microcirculation......Page 514 Acknowledgments......Page 515 References......Page 516 23.2 Cardiac Thermodynamics......Page 528 23.2.2 Heat Production......Page 529 23.2.4 Thermodynamic Efficiency and Entropy Creation......Page 530 23.2.8 Cross-Bridge Efficiency......Page 531 23.3.2 Ex Vivo Measurement of Cardiac Energetics......Page 532 23.3.2.1 Exercise Simulated in the Ex Vivo Rat Heart......Page 533 23.3.2.2 The Virtue of Varying Afterload......Page 534 23.3.3 In Vitro Measurement of Cardiac Energetics......Page 535 23.3.3.1 Additional Experimental Considerations......Page 538 23.3.3.1.2 Avoidance of Anoxia In Vitro......Page 539 23.3.4 “Total” Versus “Mechanical” Versus “Cross-Bridge” Efficiency......Page 540 23.3.5 Stress-length Area and Stress-Time Integral: Their Energetic Equivalence......Page 541 23.4.1 Basal Metabolism......Page 542 23.4.1.2 Influence of Metabolic Substrate......Page 543 23.4.2.1 The Heat–Stress Relation......Page 544 23.4.2.3 The V≐̸O2–PVA Relation......Page 545 23.4.3 Cross-Bridge Heat......Page 546 23.5.3 Cross-Bridge Cycling......Page 548 23.5.5 Model Details......Page 549 23.5.7 In Silico Simulation of Exercise......Page 550 23.6 Effect of Acute Exercise on Global Cardiac Energetics......Page 553 23.6.2 Activation Metabolism......Page 554 23.7 Conclusions......Page 555 References......Page 556 24.2 Static Exercise......Page 564 24.2.1 Onset of exercise......Page 565 24.2.2 Sustained Static Exercise......Page 569 24.2.3 Central Command Versus the Exercise Pressor Reflex......Page 570 24.2.5 Arterial Baroreceptors......Page 572 24.2.6 Standing......Page 573 24.3.1 Onset of Exercise......Page 574 24.3.2 Sustained (Steady-State) Exercise......Page 575 24.3.4 Central Command Versus the Exercise Pressor Reflex......Page 576 24.3.5 Autonomic Control of Heart Rate and Blood Pressure......Page 578 References......Page 579 25.1 Introduction......Page 584 25.2.1 Exercise Intolerance in Chronic Heart Failure......Page 585 25.2.3 Skeletal Muscle Atrophy and the Ubiquitin Proteasome System......Page 586 25.4.1 Neural Control Mechanisms During Exercise......Page 587 25.5.1 The Exercise Pressor Reflex in Chronic Heart Failure......Page 589 25.6.1 Effect of Exercise Training on the Exercise Pressor Reflex in Health......Page 591 25.6.2 Effect of Exercise Training on the Exercise Pressor Reflex in Chronic Heart Failure and Hypertension......Page 592 25.7 Mechanisms Underlying the Beneficial Effect of Exercise Training on the Exaggerated Exercise Pressor Reflex in Chronic.........Page 593 25.7.3 The TRPV1 Receptors Are Involved in the Mechanism by Which Exercise Training Prevents the Desensitization of Group I.........Page 594 25.7.4 Other Potential Mechanisms......Page 595 References......Page 597 Index......Page 604 Back Cover......Page 619