Intro to Biomechanics

1. Intro to Biomechanics

2. The Study of HumanLocomotion Historical Perspective

3. Significant Periods • Antiquity - 650 B.C. - 200 A.D. • Middle Ages - 200 A.D. - 1450 A.D. • Italian Renaissance 1450 A.D. - 1600 A.D. • Scientific Revolution 1600 A.D. - 1730 A.D. • Enlightenment 1730 A.D. - 1800 A.D. • The Gait Century 1800 A.D. - 1900 A.D. • The 20th Century 1900 A.D. – 1980 A.D. • The Computer Age 1900 A.D………present

4. Significant People/Events Pythagoras - all phenomena expained by numbers Hipprocrates - Scientific method applied to medicine Aristotle - Wrote “About the Movement of Animals” Herophilos - Foundation of modern anatomy Archimedes - Math and mechanics, C of G., buoyancy Galen - Sports Medicine Doc, “On the Use of Parts”, “On the Movements of Muscles” Antiquity - 650 B.C. - 200 A.D.

5. Antiquity - 650 B.C. - 200 A.D. Instruction concerning a dislocation of a vertebra of the neck: “if you examine a man having a dislocation of the a vertebra of his neck, should you find him unconscious of his arms and legs on account of it......then you should say an ailment which cannot be treated “ Edwin Smith Papyrus (1800) – Egyptian circa 600 BC

6. The Middle Ages - 200 A.D. - 1450 A.DRelevance to the Study of Locomotion • Interest in anatomy, physiology, and locomotion discouraged. • Greek and Roman Art depiction of human movement remained

7. The Renaissance - 1450 A.D. - 1600 A.D. • Significant People/Events • Individual genius flourished • Leonardo da Vinci - artist, scientist; anatomical studies of bone, muscle, nerve through dissection. He described the mechanics of the body during standing, walking up and downhill, rising from a sitting position, jumping, and human gait. • Versalius - described muscle function and related to movement, advocated human dissection

8. Significant People/Events Intellectual freedom highly respected Experimentation - the basis of the scientific method Galileo - Studied human jumping, horse gait, structure of bone Harvey - described blood flow through heart Descartes - Cartesian coordinate system Borelli - the “Father” of biomechanics, wrote “Du Moto Animalium”; used geometry to describe walking, running, jumping, described muscle contraction Newton - Laws of motion and gravity The Scientific Revolution - 1600 A.D. - 1730 A.D.

9. The Renaissance - 1450 A.D. - 1600 A.D. Borelli – Estimated the center of mass of nude men by having them stretch out on a rigid platform supported on a knife edge. The platform was then repositioned until is balanced, thereby indicating a location corresponding to the center of mass for the entire body.

10. Significant People/Events Muybridge - motion analysis - horses, people; Animals in Motion, The Human Figure in Motion Weber brothers - “On the Mechanics of the Gait Tools” 150 hypotheses Marey - (huge) the first gait lab (force plate, cinematography, synchronized cine and force Braune and Fisher - 3d analysis of gait, mathematical analysis, “light” suits Duchenne - EMG The Gait Century - 1800 A.D. - 1900 A.D.

11. Étienne-Jules Marey (1830-1904) Studied soldiers…energy cost of locomotion…..economy of movement Unique techniques

12. Eduard Muybridge - The “Father” of Cinematography

13. The Computer Age 1980 AD …. • Significant People/Events • Abdel, Azziz, and Carrera - developed the DLT • Basmajian - expanded EMG techniques and understanding of muscle function • Winter - refined experimental techniques for the analysis of gait • Sutherland - classic studies on the development of gait in children, and influence of CP on gait

14. The Computer Age 1980 AD …. • Murray - classic studies on adult gait • Gage, Sutherland, and Perry - integration of gait analysis in surgical treatment of orthopaedic disorder • Development of the Miocrocomputer • Nigg, Cavanagh,Bates - biomechanical assessment of running gait • Expansion and refinement of video technology • Greaves - Video Processor • Founding of the Clinical Gait and Movement AnalysisSociety

15. Societies • Clinical Gait and Movement AnalysisSociety • American Society of Biomechanics • International society of Biomechanics • Orthopedic Research Society • BioMedical Engineering Society

16. THE STUDY AND ANALYSIS OF HUMAN MOVEMENT • During the past decade the term BIOMECHANICS has emerged as an area of inquiry in the sport science domain. • Biomechanics is based on NEWTON'S LAWS and involves the study of the motion of bodies and the interrelationships among the forces acting on these bodies.

17. THE STUDY AND ANALYSIS OF HUMAN MOVEMENT BIOMECHANICS: BIO = LIVING • MECHANICS = FORCES & EFFECTS • The application of mechanics to the living organism • Involves the principles of anatomy, engineering and physics in the descriptions and analysis of movement. • Has many diverse applications to all biological systems • The study of biological structures, processes and functions by applying the methods and principles of mechanics

18. QUANTITATIVE VS QUALITATIVE • Both kinematics and kinetics can be analyzed using a quantitative or qualitative approach • A quantitative analysis requires a numerical evaluation of an individual’s movement • Qualitative analysis involves a systematic analysis of movement based on biomechanical concepts but without actual measurement

19. QUALITATIVE ANALYSIS • Qualitative analysis involves a systematic analysis of movement based on biomechanical concepts but without actual measurement

20. AREAS OF STUDY, RESEARCH AND PRACTICE • Sport and Exercise Science • Coaching • Ergonomics • Equipment Design • Gait & Locomotion • Orthopedics - Rehabilitation -Physiotherapy, Occupational Therapy • Prosthetics and Orthotics • Motor Control • Computer Simulation

21. Biomechanic’s Schema Rigid Body Mechanics kinematics kinetics linear curvilinear statics dynamics angular parabolic

22. KINEMATICS • Describes the motion of a body without reference to the forces causing it. Kinematics examines how, when, and where a body moves.

23. SEGMENTAL ANALYSIS • We often make the assumption that the human skeleton can be represented as a series of links. Researchers have used everything from cones to spheres to form the links which best approximated the complexity of the human body. However, by far the most widely adopted and simplest link system representation is the stick man.

25. The stick man uses straight sticks to represent each of the links. In any case, regardless of the shapes which are used we also make the assumption that the human link system is a system of rigid bodies connected at the joints

27. Videotape Analysis: A Functional Capacity Lift

28. Graphical Analysis

30. KINETICS • examines the causes of motion, the internal and external forces that cause motion or cause a body to remain at rest, and the interactions between these forces. There are two branches of kinetics; STATICS and DYNAMICS

31. JOINTREACTIONFORCES

32. MECHANICS • Rigid body mechanics are based on the assumption that a solid body is considered to be a rigid body if the distance between the particles remains fixed when a force is applied.

33. STATICS: Statics refers to situations where the body or object remains at rest, or is moving at a constant speed in a state of equilibrium. Equilibrium is a balanced state in which there is no acceleration.

34. DYNAMICS: Dynamics deals with the changes in motion brought on by unbalanced forces.

35. QUANTITATIVE VS QUALITATIVE • Both kinematics and kinetics can be analyzed using a quantitative or qualitative approach • A quantitative analysis requires a numerical evaluation of an individual’s movement • Qualitative analysis involves a systematic analysis of movement based on biomechanical concepts but without actual measurement

36. Fax

37. EMG • BASED ON RELATIONSHIP BETWEEN FORCE AND THE ELECTRICAL ACTIVITY ACROSS THE MUSCLE MEMBRANE • EXAMPLE: Which exercise is best for rehabilitation of a particular muscle?

38. ELECTROMYOGRAPHY-EMG Raw EMG Full wave Rectify Linear Envelope Integrate over contraction