Understanding mammalian locomotion: concepts and applications

Content: List of Contributors xv     Preface xvii     Chapter 1 Concepts Through Time: Historical Perspectives on Mammalian Locomotion 1 John E. A. Bertram     1.1 Introduction 1     1.2 The ancients and the contemplation of motion 2     1.3 The European Renaissance and foundations of the age of discovery 3     1.4 The era of technological observation 5     1.5 Physiology and mechanics of terrestrial locomotion     cost and consequences 7     1.6 Comparative studies of gait 10     1.6 Re  ]interpreting the mechanics: a fork in the road, or simply seeing the other side of the coin? 13     1.7 The biological source of cost 13     1.8 The physical source of cost (with biological consequences)     the road less traveled 14     1.9 Conclusions 21     References 21     Chapter 2 Considering Gaits: Descriptive Approaches 27 John E. A. Bertram     2.1 Introduction 27     2.2 Defining the fundamental gaits 28     2.3 Classifying and comparing the fundamental gaits 30     2.4 Symmetric gaits 32     2.5 A symmetric gaits 34     2.6 Beyond    Hildebrand plots    40     2.7 Statistical classification 43     2.8 Neural regulation and emergent criteria 45     2.9 Mechanical measures as descriptions of gaits 47     2.10 Conclusion 47     References 48     Chapter 3 Muscles as Actuators 51 Anne K. Gutmann and John E. A. Bertram     3.1 Introduction 51     3.2 Basic muscle operation 52     3.2.1 Sliding filament theory     the basis for cross  ]bridge theory 52     3.2.2 Basic cross  ]bridge theory 52     3.2.3 Multi  ]state cross  ]bridge models 57     3.3 Some alternatives to cross  ]bridge theory 59     3.4 Force production 60     3.4.1 Isometric force production 60     3.4.2 Non  ]isometric force production 63     3.5 The Hill  ]type model 66     3.6 Optimizing work, power, and efficiency 68     3.7 Muscle architecture 70     3.7.1 The sarcomere as the fundamental contractile unit 70     3.7.2 Muscle geometry 70     3.7.3 Elastic energy storage and return 72     3.7.4 Damping/energy dissipation 72     3.8 Other factors that influence muscle performance 73     3.8.1 Fiber type 73     3.9 A ctivation and recruitment 75     3.10 What does muscle do best? 76     References 76     Chapter 4 Concepts in Locomotion: Levers, Struts, Pendula and Springs 79 John E. A. Bertram     4.1 Introduction 79     4.2 The limb: How details can obscure functional role 83     4.3 Limb function in stability and the concept of the    effective limb    85     4.3.1 Considering the mechanisms of stability 85     4.3.2 The role of the effective limb 88     4.4 Levers and struts 89     4.5 Ground reaction force in gaits 92     4.5.1 Trot 94     4.5.2 Walk 96     4.5.3 Gallop 97     4.6 The consequence of applied force: CoM motion, pendula and springs 98     4.7 Energy exchange in locomotion     valuable or inevitable? 102     4.8 Momentum and energy in locomotion: dynamic fundamentals 103     4.9 Energy     lost unless recovered, or available unless lost? 104     References 105     Chapter 5 Concepts in Locomotion: Wheels, Spokes, Collisions and Insight from the Center of Mass 111 John E. A. Bertram     5.1 Introduction 111     5.2 Understanding brachiation: an analogy for terrestrial locomotion 112     5.3 Bipedal walking: inverted pendulum or inverted    collision  ]limiting brachiator analog   ? 117     5.4 Basic dynamics of the step  ]to  ]step transition in bipedal walking 120     5.5 Subtle dynamics of the step  ]to  ]step transition in bipedal walking and running 124     5.6 Pseudo  ]elastic motion and true elastic return in running gaits 130     5.7 Managing CoM motion in quadrupedal gaits 131     5.7.1 Walk 132     5.7.2 Trot 133     5.7.3 Gallop 133     5.8 Conclusion 138     References 139     Chapter 6 Reductionist Models of Walking and Running 143 James R. Usherwood     6.1 Part 1: Bipedal locomotion and    the ultimate cost of legged locomotion?    143     6.1.1 Introduction 143     6.1.2 Reductionist models of walking 144     6.1.3 The benefit of considering locomotion as inelastic 150     6.2 Part 2: quadrupedal locomotion 158     6.2.1 Introduction 158     6.2.2 Quadrupedal dynamic walking and collisions 158     6.2.3 Higher speed quadrupedal gaits 161     6.2.4 Further success of reductionist mechanics 162     Appendix A: Analytical approximation for costs of transport including legs and    guts and gonads    losses 166     6A.1 List of symbols 166     6A.2 Period definitions for a symmetrically running biped 166     6A.3 Ideal work for the leg 167     6A.4 Vertical work calculations for leg 168     6A.5 Horizontal work calculations for leg 169     6A.6 Hysteresis costs of    guts and gonads    deflections 169     6A.7 Cost of transport 170     References 170     Chapter 7 Whole  ]Body Mechanics: How Leg Compliance Shapes the Way We Move 173 Andre Seyfarth, Hartmut Geyer, Susanne Lipfert, J. Rummel, Yvonne Blum, M. Maus and D. Maykranz     7.1 Introduction 173     7.2 Jumping for distance     a goal  ]directed movement 175     7.3 Running for distance     what is the goal? 177     7.4 Cyclic stability in running 178     7.5 The wheel in the leg     how leg retraction enhances running stability 179     7.6 Walking with compliant legs 180     7.7 A dding an elastically coupled foot to the spring  ]mass model 184     7.8 The segmented leg     how does joint function translate into leg function? 185     7.9 Keeping the trunk upright during locomotion 187     7.10 The challenge of setting up more complex models 188     Notes 190     References190     Chapter 8 The Most Important Feature of an Organism   s Biology: Dimension, Similarity and Scale 193 John E. A. Bertram     8.1 Introduction 193     8.2 The most basic principle: surface area to volume relations 194     8.3 A ssessing scale effects 197     8.4 Physiology and scaling 198     8.5 The allometric equation: the power function of scaling 203     8.6 The standard scaling models 207     8.6.1 Geometric similarity 208     8.6.2 Static stress similarity 209     8.6.3 Elastic similarity 209     8.7 Differential scaling     where the limit may change 210     8.7.1 A ssessing the assumptions 215     8.8 A fractal view of scaling 215     8.9 Making valid comparisons: measurement, dimension and functional criteria 217     8.9.1 Considering units 217     8.9.2 Fundamental and derived units 219     8.9.3 Froude number: a dimensionless example 222     References 223     Chapter 9 Accounting for the Influence of Animal Size on Biomechanical Variables: Concepts and Considerations 229 Sharon Bullimore     9.1 Introduction 229     9.2 Commonly used approaches to accounting for size differences 230     9.2.1 Dividing by body mass 230     9.2.2 Dimensionless parameters 232     9.3 Empirical scaling relationships 237     9.4 Selected biomechanical parameters 238     9.4.1 Ground reaction force 238     9.4.2 Muscle force 239     9.4.3 Muscle velocity 242     9.4.4 Running speed 242     9.4.5 Jump height 244     9.4.6 Elastic energy storage 246     9.5 Conclusions 247     Acknowledgements 247     References 247     Chapter 10 Locomotion in Small Tetrapods: Size  ]Based Limitations to    Universal Rules    in Locomotion 251 Audrone R. Biknevicius, Stephen M. Reilly and Elvedin Kljuno     10.1 Introduction 251     10.2 A ctive mechanisms contributing to the high cost of transport in small tetrapods 254     10.3 Limited passive mechanisms for reducing cost of transport in small tetrapods 255     10.4 Gait transitions from vaulting to bouncing mechanics 257     10.5 The    unsteadiness    of most terrestrial locomotion 262     Appendix     a model of non  ]steady speed walking 265     10A.1 Spring  ]mass inverted pendulum model of walking 265     10A.2 Recovery ratio calculation 269     References 271     Chapter 11 Non  ]Steady Locomotion 277 Monica A. Daley     11.1 Introduction 277     11.1.1 Why study non  ]steady locomotion? 278     11.2 A pproaches to studying non  ]steady locomotion 279     11.2.1 Simple mechanical models 280     11.2.2 Research approaches to non  ]steady locomotion 281     11.3 Themes from recent studies of non  ]steady locomotion 282     11.3.1 Limits to maximal acceleration 282     11.3.2 Morphological and behavioral factors in turning mechanics 283     11.4 The role of intrinsic mechanics for stability and robustness of locomotion 288     11.4.1 Some definitions 289     11.4.2 Measures of sensitivity and robustness 290     11.4.3 What do we learn about stability from simple models of running? 291     11.4.4 Limitations to stability analysis of simple models 295     11.4.5 The relationship between ground contact conditions and leg mechanics on uneven terrain 296     11.4.6 Compromises among economy, robustness and injury avoidance in uneven terrain 298     11.5 Proximal  ]distal inter  ]joint coordination in non  ]steady locomotion 299     References 302     Chapter 12 The Evolution of Terrestrial Locomotion in Bats: the Bad, the Ugly, and the Good 307 Daniel K. Riskin, John E. A. Bertram and John W. Hermanson     12.1 Bats on the ground: like fish out of water? 307     12.2 Species  ]level variation in walking ability 308     12.3 How does anatomy influence crawling ability? 309     12.4 Hindlimbs and the evolution of flight 311     12.5 Moving a bat   s body on land: the kinematics of quadrupedal locomotion 315     12.6 Evolutionary pressures leading to capable terrestrial locomotion 318     12.7 Conclusions and future work 319     Acknowledgements 320     References 320     Chapter 13 The Fight or Flight Dichotomy: Functional Trade  ]Off in Specialization for Aggression Versus Locomotion 325 David R. Carrier     13.1 Introduction325     13.1.1 Why fighting is important 327     13.1.2 Size sexual dimorphism as an indicator of male  ]male aggression 328     13.2 Trade  ]offs in specialization for aggression versus locomotion 329     13.2.1 The evolution of short legs     specialization for aggression? 329     13.2.2 Muscle architecture of limbs specialized for running versus fighting 331     13.2.3 Mechanical properties of limb bones that are specialized for running versus fighting 334     13.2.4 The function of foot posture: aggression versus locomotor economy 334     13.3 Discussion 338     References 341     Chapter 14 Design for Prodigious Size without Extreme Body Mass: Dwarf Elephants, Differential Scaling and Implications for Functional Adaptation 349 John E. A. Bertram     14.1 Introduction 349     14.2 Elephant form, mammalian scaling and dwarfing 351     14.2.1 Measurements 356     14.2.2 Observations 356     14.3 Interpretation 357     Acknowledgements 364     References 364     Chapter 15 Basic Mechanisms of Bipedal Locomotion: Head  ]Supported Loads and Strategies to Reduce the Cost of Walking 369 James R. Usherwood and John E. A. Bertram     15.1 Introduction 369     15.2 Head  ]supported loads in human  ]mediated transport 370     15.2.1 Can the evidence be depended upon? 371     15.3 Potential energy saving advantages 373     15.4 A simple alternative model 376     15.5 Conclusions 382     References 382     Chapter 16 Would a Horse on the Moon Gallop? Directions Available in Locomotion Research (and How Not to Spend Too Much Time Exploring Blind Alleys) 385 John E. A. Bertram     16.1 Introduction 385     References 392     Index 393