Fundamentals of Biomechanics

Citation

Knudson, D. (2021). Fundamentals of Biomechanics (3rd ed.). Springer.

Chapter Summary

The third edition is a short book of about 250 pages: ten chapters in three parts (about 185 pages), followed by five appendices (a glossary of biomechanics terms, conversion factors, suggested answers to the odd-numbered review questions, a review of right-angle trigonometry, and a form for the qualitative evaluation of biomechanical principles) and a set of twelve laboratory activities. Each chapter opens with "key questions" (what you need to know to begin, why you need to know it, and the key idea), and ends with a summary, review questions, suggested reading and internet resources. The publisher describes more than 160 figures of real human movement and case studies of actual technique, and the preface mentions application boxes and interdisciplinary-issues boxes linking biomechanics with the other sport sciences.

Part I (Chapters 1–3)

Chapter 1: Introduction to Biomechanics of Human Movement. Defines biomechanics and kinesiology, explains why professionals need biomechanics, and introduces the research evidence available to practitioners, including a hierarchy of research designs from case studies to meta-analyses.

Chapter 2: Anatomical Description and Its Limitations. Reviews directional terms, joint motions and muscle structure, then argues that knowledge of gross anatomy alone cannot explain how muscles actually create and control movement.

Chapter 3: Fundamentals of Biomechanics and Qualitative Movement Diagnosis. Introduces the nine principles of biomechanics that organise the rest of the book (force–motion, force–time, inertia, range of motion, balance, coordination continuum, segmental interaction, optimal projection and spin), some of which derive from Newton's laws, and shows how they feed into the qualitative diagnosis of movement technique.

Part II (Chapters 4–8)

The book's introduction to this part describes it as covering the key mechanical properties of biological tissues, kinematics, kinetics and fluids, with lab activities exploring both qualitative and quantitative analysis.

Chapter 4: Mechanics of the Musculoskeletal System. The mechanical behaviour of tissues and muscles: how tissues respond to loads, and the mechanical characteristics of muscle, including the build-up of tension, the force–time relationship and the stretch-shortening cycle.

Chapter 5: Linear and Angular Kinematics. Describing motion: distance and displacement, speed and velocity, acceleration, and their angular equivalents, calculated with algebra over time intervals; the chapter assumes musculoskeletal anatomy and algebra.

Chapter 6: Linear Kinetics. The causes of linear motion: Newton's laws, forces and their effects over time, and mechanical work, energy and power, illustrated with examples from exercise.

Chapter 7: Angular Kinetics. Torques and the causes of rotation, static equilibrium applied to lifting, and the calculation of the body's centre of gravity.

Chapter 8: Fluid Mechanics. How air and water affect movement, including drag and the Magnus effect on spinning balls such as a pitched baseball.

Part III: Applications of Biomechanics in Qualitative Diagnosis of Movement (Chapters 9–10)

Chapter 9: Applying Biomechanics in Teaching and Coaching. Guided examples of qualitative diagnosis of sport skills, beginning with kicking, that combine the nine principles with other sport sciences.

Chapter 10: Applying Biomechanics in Exercise and Rehabilitation. Similar guided examples for strength and conditioning and the allied health professions (athletic training, physical therapy and occupational therapy).

Key Concepts

Part I: Foundations

• Qualitative movement diagnosis: the systematic observation and evaluation of technique to find and correct the causes of poor performance or injury risk.
• Limits of functional anatomy: why naming a muscle's action from its attachments often misdescribes what it does in real movement.
• Nine principles of biomechanics: general rules, from force–motion to spin, used throughout the book to apply mechanics in practice.

Part II: Biological and mechanical bases

• Tissue loading: how biological tissues respond to the forces placed on them.
• Stretch-shortening cycle: the enhanced force produced when a muscle is stretched just before it shortens.
• Kinematics versus kinetics: describing motion as opposed to explaining the forces and torques that cause it.
• Work, energy and power: mechanical measures of how forces change the motion of the body and of loads.
• Fluid forces: drag and the Magnus effect on bodies and projectiles moving through air and water.

Part III: Applications

• Evidence-based practice: combining the principles with research evidence and other kinesiology subdisciplines when advising performers or clients.

Critical Analysis

Strengths

• A small set of principles for practice. The nine principles give students without an engineering background a usable framework, and the appendix form for evaluating the principles turns them into a checklist for qualitative analysis.
• Conceptual and algebra-level. The mathematics stays at algebra and right-angle trigonometry, with a trigonometry review in an appendix. Endorsements of the second edition quoted by the publisher, from Glenn Fleisig of the American Sports Medicine Institute and Jani Macari Pallis of the International Sports Engineering Association, praise its clarity and its separate treatment of the biological and mechanical sides.
• Active learning. Twelve laboratory activities, designed for small groups, range from finding biomechanical sources and functional anatomy to range-of-motion analysis, the force–motion principle, calculating centre of gravity, the Magnus effect in pitching, comparing skilled and novice performers, comparing training modes and diagnosing walking gait. Answers to the odd-numbered review questions support self-study.
• Built for kinesiology professions. Part III and the case studies apply the principles in teaching and coaching and in exercise and rehabilitation, which matches the careers of most kinesiology students.

Limitations

• Little quantitative analysis. Calculus and vector algebra are not used, and static analysis is limited to simple models such as lifting. Biomedical engineering students will need a quantitative text for problem solving.
• Short and selective. At about 185 pages of main text, each mechanical topic receives one chapter; the Part III applications cover two professional settings only.
• Human-movement scope. The book is about sport, exercise and rehabilitation movement; it does not treat cell mechanics, cardiovascular or respiratory biomechanics, or implant design.

Where It Fits in the Course

Knudson is the conceptual, algebra-level entry point in this course. Özkaya, Leger, Goldsheyder and Nordin's Fundamentals of Biomechanics: Equilibrium, Motion, and Deformation covers the musculoskeletal system with full statics, dynamics and mechanics of materials, using calculus; it is the natural next step for students who need to solve force problems. Ethier and Simmons's Introductory Biomechanics: From Cells to Organisms is an engineering text that assumes solid and fluid mechanics and ranges from cells to whole-body movement.

Humphrey and O'Rourke's An Introduction to Biomechanics develops continuum mechanics for solids and fluids, and Y. C. Fung's Biomechanics: Mechanical Properties of Living Tissues is a graduate monograph on constitutive behaviour; both are well beyond Knudson. Peterson and Bronzino's Biomechanics: Principles and Applications is an edited reference for looking up specific topics. Kinesiology and physical education students may need only Knudson; engineering students can use it as a quick conceptual introduction before Özkaya or Ethier and Simmons.

How to Use This Book

The book suits undergraduates in kinesiology, exercise science, physical education, athletic training and physical therapy, and engineering students who want a conceptual introduction to human movement. School algebra and trigonometry are enough, together with some basic anatomy, which Chapter 2 reviews.

A practical plan:

• Start with Chapters 1–3. Chapter 3 introduces the nine principles; return to it often, since every later chapter refers back to them.
• Core mechanics: Chapters 4–7 in order. Work through the calculations in Chapters 5–7 and pair each chapter with its lab activity (for example, Lab 7B on centre of gravity).
• Optional or according to interest: Chapter 8 on fluids for swimming, throwing and ball sports.
• Applications: Chapter 9 for teaching and coaching, Chapter 10 for exercise and rehabilitation; read the one matching your career, then try the other.

Use the "key questions" at the start of each chapter to orient yourself, and answer the review questions, checking the odd-numbered ones in Appendix C. Use the Appendix E form to practise qualitative diagnosis on video of real movements. Students heading into engineering should follow the book with a quantitative text.