1KIN 430BiomechanicsLead Instructor:Dr. Brian UmbergerOffice: 107 Totman BuildingEmail: [email protected] Teaching Assistants:Mr. Ryan Wedge Mr. Russell JohnsonOffice: Rm 21, Totman Bld Rm 21, Totman BldEmail: [email protected] [email protected] © 2014Brian R. Umberger, Ph.D.University of Massachusetts AmherstLearning Management SystemMoodle: http://moodle.umass.edu/course name: KIN430-SEC01 FA14What is Biomechanics?Some common definitions:The study of forces and motion inbiological systemsThe application of mechanical principles in the study of living organismsThe science concerned with internal and external forces acting on the human body,and the effects produced by those forcesWhat is Kinesiology?The science and practice of human movementIncludes: biomechanics, exercise physiology, motor behavior, exercisepsychology, athletic training, physical activity and health, etc.What about “Sports Medicine”?A broad term that encompasses all clinical and scientific aspects of sports and exercise2BiomechanicsThe “bio” partBiologyOrganismal BiologyOther areas of biologyAnatomy PhysiologyGross AnatomySystems PhysiologyBiomechanicsThe “mechanics” partPhysicsMechanicsOther areas of physicsStatics DynamicsKinematics KineticsWhen did biomechanics start?• Ancient Greeks (Plato, Aristotle) first considered scientific aspects of human movement (300 - 400 BC)• Galen developed scientific approach to anatomy; became first “sports medicine doctor” attending to the Roman gladiators (200 AD)• Borelli more fully integrated physiology and mechanics, published De Motu Animalium (The Movement of Animals; mid 1600’s)• Newton formalized laws of mechanics that govern motion of the human body (and most other things; late 1600’s)Etienne Marey (1838-1904)Edweard Muybridge (1830-1904)Marey & Muybridge developed modern motion analysis by using sequential & multiple exposure photographyMarey was the true scientist of the two, but Muybridge is better known for his incredible collection of photographs of humans & other animals in motionWhen did biomechanics start?3Why Study Biomechanics?• Better understand how the body functions• Address issues related to human health and performance• Important knowledge for:– Kinesiologists / Movement Scientists – Athletic Trainers / Physical Therapists– Exercise Instructors / Personal Trainers– Coaches / Sports Scientists– Biomedical Engineers– Orthopedic SurgeonsBiomechanics - ApplicationsAnalysis of sports performance Sports injury mechanismsGait analysis OrthopaedicsBiomechanics - ApplicationsEquipment design Forensic biomechanics Equine BiomechanicsBiomechanics at UMass?Biomechanics Laboratory - Current Research:• Changes in gait mechanics with aging or injury• Muscle mechanics and postural control• Energetic aspects of human locomotion • Computer simulation of human movement4Dimensions and UnitsIn biomechanics, we deal with three basic quantities, mass, length, and time, and several derived quantitiesQuantity Dimension Unit (SI system)mass M kilogramlength L metertime T secondDerived quantities (two examples)force M L T-2newton [1N = 1 (kgm)/s2]work M L2T-2joule [1 J = 1 Nm]Forms of Motion• Linear• Angular• GeneralLinear Motion (Translation)Movement of a body such that all parts of it travel exactly the same distance, in the same direction, in the same timeLinear Motion (Translation)Rectilinear motion5Linear Motion (Translation)Curvilinear MotionAngular Motion (Rotation)Movement of a body along a circular path about a line is space such that all parts of the body travel through the same angle, in the same direction, in the same time.This line, which may or may not pass through the body itself, is known as the axis of rotation and lies at right angles to the plane of motion of the body.Angular MotionAngular vs Curvilinear MotionAngular Motion Curvilinear MotionP1P3P2P1P3P2lines are different lengthslines are the same length6General MotionCombined linear and angular motionMost human activities involve both linear and angular movement, and are thus forms of general motionBasic Kinetic ConceptsStatics – study of forces acting on a body:− at rest; velocity is zero− in uniform motion; velocity is constant but not zero (uncommon in human movement)Dynamics – study of bodies in motion:– kinematics: description of motion, independent of the cause– kinetics: the actual causes of motionBasic Kinetic ConceptsInertia – the property of a body causing a resistance to change in state of motionMass – the quantity of matter making up an object; measure of resistance to change in linear motion (Not the same as weight!)Force – a push or pull on a body tending to change the motion of the body (Note: direct contact is not required for a force to cause acceleration: e.g., gravity or magnetic force)Basic Kinetic ConceptsCenter of Mass / Center of Gravity:– Imaginary point about which all the mass/weight of a body is distributed– In human body, approximately at the level of the navel top-to-bottom, and midway front-to-backWeight:– Attractive force that the Earth applies to a body– Equal to the mass of a body in kg, times the acceleration due to gravity (9.81 m/s2)W = mg7Representing VectorsVector quantities, such as forces, are represented graphically using arrowsLength of the arrow denotes the magnitude of the vectorOrientation of the arrow denotes the direction of the vectorF1F2F1F2F3Things to do:• Get textbook (if you haven’t already)• Read Chapter 1 in Hamill• Do “Units” reading (on moodle)• Start Chapter 8 in Hamill• Print out and read handout for first lab(on moodle)These notes are to be used only as a study aid in conjunction with the course KIN 430 Biomechanics at the University of Massachusetts Amherst. 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