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Introduction 1 About This Book 1 Foolish Assumptions 2 Icons Used in This Book 3 Beyond the Book 3 Where to Go from Here 4
Part I: Getting Started with Biomechanics 5
Chapter 1: Jumping Into Biomechanics 7 Analyzing Movement with Biomechanics 7 Mechanics 8 Bio 9 Expanding on Mechanics 10 Describing motion with kinematics 11 Causing motion with kinetics 13 Putting Biomechanics to Work 14
Chapter 2: Reviewing the Math You Need for Biomechanics 15 Getting Orientated 16 Brushing Up on Algebra 17 Following the order of operations 17 Defining some math operations 19 Isolating a variable 20 Interpreting proportionality 22 Looking for the Hypotenuse 23 Using the Pythagorean theorem 24 De-tricking trigonometric functions: SOH CAH TOA 26 Unvexing Vector Quantities 31 Resolving a vector into components 33 Composing a vector from components 35
Chapter 3: Speaking the Language of Biomechanics 37 Measuring Scalars and Vectors 38 Standardizing a Reference Frame 39 Directing your attention to locations of the body 40 Referencing planes and axes 40 Describing Movement: Kinematics 42 Typecasting motion: Linear, angular, and general 42 Describing how far: Distance and displacement 43 Describing how fast: Speed and velocity 44 Changing velocity: Acceleration 45 Pushing and Pulling into Kinetics 45 Forcing yourself to understand Newton''s laws of motion 47 Using the impulse-momentum relationship 49 Working with Energy and Power 49 Mechanical work 49 Mechanical energy 50 Mechanical power 51 Turning Force into Torque 51 Dealing with Measurement Units 51 Using the Neuromusculoskeletal System to Move 52 The skeletal system 53 The muscular system 53 The nervous system 55
Part II: Looking At Linear Mechanics 57
Chapter 4: Making Motion Change: Force 59 Pushing and Pulling: What Is Force? 59 Working with Force Vectors 65 Using the force components to find the resultant 66 Resolving a force into components 68 Classifying Forces 69 Contact and noncontact forces 69 Internal and external forces 70 Feeling the Pull of Gravity 74 Slipping, Sliding, and Staying Put: Friction Is FμN 76 Materials do matter: The coefficient of friction ( μ ) 80 Squeezing to stick: Normal reaction force (N) 81
Chapter 5: Describing Linear Motion: Linear Kinematics 83 Identifying Position 84 Describing How Far a Body Travels 85 Distance.85 Displacement 86 Describing How Fast a Body Travels 88 Speed 89 Velocity 90 Momentum 92 Speeding Up or Slowing Down: Acceleration 92 Constant acceleration 95 Projectile motion 95
Chapter 6: Causing Linear Motion: Linear Kinetics 103 Clarifying Net Force and Unbalanced Force 103 Newton''s First Law: The Law of Inertia 106 Newton''s Third Law: The Law of Equal and Opposite Action-Reaction 107 Newton''s Second Law: The Law of Acceleration 109 Deriving the impulse-momentum relationship from the law of acceleration 112 Applying the impulse-momentum relationship for movement analysis 114
Chapter 7: Looking At Force and Motion Another Way: Work, Energy, and Power 119 Working with Force 120 Energizing Movement 122 Kinetic energy 123 Potential energy 124 Conserving Mechanical Energy 128 Powering Better Performance 130 The Work-Energy Relationship 131
Part III: Investigating Angular Mechanics 137
Chapter 8: Twisting and Turning: Torques and Moments of Force 139 Defining Torque 140 Lining up for rotation: The moment arm of a force 141 Calculating the turning effect of a force 142 Measuring Torque 144 Muscling into torque: How muscles serve as torque generators 145 Resisting torque: External torques on the body 148 Expanding on Equilibrium: Balanced Forces and Torques 149 Locating the Center of Gravity of a Body 152
Chapter 9: Angling into Rotation: Angular Kinematics 157 Measuring Angular Position 157 Describing How Far a Body Rotates 160 Angular distance 161 Angular displacement 162 Describing How Fast a Body Rotates 163 Angular speed.163 Angular velocity 164 Speeding Up or Slowing Down: Angular Acceleration 165 Relating Angular Motion to Linear Motion 167 Angular displacement and linear displacement 168 Angular velocity and linear velocity 169 Angular acceleration and linear acceleration 171
Chapter 10: Causing Angular Motion: Angular Kinetics 173 Resisting Angular Motion: The Moment of Inertia 174 The moment of inertia of a segment174 The moment of inertia of the whole body 178 Considering Angular Momentum 180 Angular momentum of a rigid body 180 Angular momentum of the human body when individual segments rotate 181 A New Angle on Newton: Angular Versions of Newton''s Laws 181 Maintaining angular momentum: Newton''s first law.182 Changing angular momentum: Newton''s second law 186 Equal but opposite: Newton''s third law189 Changing Angular Momentum with Angular Impulse 191
Chapter 11: Fluid Mechanics 193 Buoyancy: Floating Along 193 Considering Force Due to Motion in Fluid 197 Causing drag in a fluid 198 Causing lift in a fluid 201
Part IV: Analyzing the "Bio" of Biomechanics 205
Chapter 12: Stressing and Straining: The Mechanics of Materials 207 Visualizing Internal Loading of a Body 208 Applying Internal Force: Stress 210 Normal stress 212 Shear stress 217 Responding to Internal Force: Strain 219 Determining tensile strain 221 Determining compressive strain 221 Determining shear strain 222 Straining from Stress: The Stress-Strain Relationship 223 Give and go: Behaving elastically 224 Give and stay: Behaving plastically 224
Chapter 13: Boning Up on Skeletal Biomechanics 227 What the Skeletal System Does 228 How Bones Are Classified 228 The Materials and Structure of Bones 230 Materials: What bones are made of 231 Structure: How bones are organized 232 Connecting Bones: Joints 234 Immovable joints 234 Slightly movable joints 234 Freely movable joints 235 Growing and Changing Bone 237 Changing bone dimensions 238 Stressing bone: The effects of physical activity and inactivity 239
Chapter 14: Touching a Nerve: Neural Considerations in Biomechanics 247 Monitoring and Controlling the Body: The Roles of the Nervous System 248 Outlining the Nervous System 248 The central nervous system 250 The peripheral nervous system 250 Zeroing In on Neurons 251 Parts of neurons 251 Types of neurons 251 Controlling Motor Units 259 Motor unit recruitment 261 Rate coding 261
Chapter 15: Muscling Segments Around: Muscle Biomechanics 263 Characterizing Muscle 263 Seeing How Skeletal Muscles Are Structured 265 The macrostructure of muscles 266 The microstructure of muscle fibers.268 Comparing Types of Muscle Activity 270 Isometric activity 271 Concentric activity 272 Eccentric activity 272 Producing Muscle Force 274 Relating muscle length and tension 274 Relating muscle velocity and tension277 Stretching before Shortening: The Key to Optimal Muscle Force 279
Part V: Applying Biomechanics 283
Chapter 16: Eyeballing Performance: Qualitative Analysis 285 Serving as a Movement Analyst 286 Evaluating the Performance 287 Identifying the goal of the movement 287 Specifying the mechanical objective 289 Determining whether the goal has been reached 290 Troubleshooting the Performance 293 Constraints on performance 293 Technique errors 294 Pitching by the phases 298 Intervening to Improve the Performance 302 Adapting the constraints on throwing performance 302 Refining technique 303
Chapter 17: Putting a Number on Performance: Quantitative Analysis 305 Converting Continuous Data to Numbers 305 Measuring Kinematics: Motion-Capture Systems 306 Collecting kinematic data 307 Processing kinematic data 308 Measuring Kinetics: Force Platform Systems 310 Collecting kinetic data 310 Processing kinetic data 312 Recording Muscle Activity: Electromyography 313 Collecting the electromyogram 314 Processing the electromyogram 315
Chapter 18: Furthering Biomechanics: Research Applications 319 Exercising in Space 319 Repairing the Anterior Cruciate Ligament 320 Running Like Our Ancestors 322 Protecting Our Beans: Helmet Design 324 Balancing on Two Legs: Harder Than You Think 326
Chapter 19: Investigating Forensic Biomechanics: How Did It Happen? 329 Collecting Information for a Forensic Biomechanics Analysis 330 Witness accounts 330 Police incident investigation reports 331 Medical records 331 Determining the Mechanism of Injury 332 Evaluating Different Scenarios 335 Ending up on the far side of the road