KIN 3309 1st Edition Lecture 2 Outline of Last Lecture I II III IV V VI VII VIII IX X XI XII XIII XIV XV XVI XVII XVIII XIX XX XXI XXII XXIII XXIV XXV XXVI Why Study Biomechanics Basic Terminology Human Movement Analysis Areas of Study Biomechanics vs Kinesiology Anatomy vs Functional Anatomy Linear vs Angular Motion Quiz Quiz Kinematics vs Kinetics TQ Statics vs Dynamics Skeleton Body Segments Reference Positions Relative Positions Flexion and Extension Abduction and Adduction Other Movement Descriptors Specialized Movement Descriptors Movement Descriptors of Foot Pronation and Supination of the Foot Reference Systems Absolute vs Relative Planes and Axes Cardinal Planes Degrees of Freedom Summary Outline of Current Lecture I Hierarchy of Stuf II Types of Solid Materials These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III Stress and Strain IV Stress Strain Curve V Quiz VI Quiz VII Musculoskeletal System VIII Functions of the Skeleton IX Architecture of Bone X Types of Bone Tissue XI Types of Bone XII Bone Tissue XIII Ossification Modeling and Remodeling XIV Bone Tissue XV What would happen if the activity of bone cells was out of balance XVI Bones and Physical Activity XVII Material Properties of Bone XVIII Quiz XIX Quiz XX Load Applied to Bone XXI Injury XXII Cartilage XXIII Articular Cartilage XXIV Fibrocartilage XXV Ligaments XXVI Stress Strain Curve for Ligaments XXVII Synovial Joint XXVIII Types of Synovial Joints XXIX Joint Degradation XXX Quiz XXXI Quiz XXXII Summary Current Lecture I Hierarchy of Stuf a Structural System b Structure c Material II Types of Solid Materials a Tensile materials i Resist being pulled on 1 resist tensile stress ii Examples 1 Silk 2 Collagen a Found in tendons skin bone muscle and more b Pliant Materials i Must deform to function properly ii Examples 1 Rubbers 2 Elastin a Found in skin and arterial wall iii Pliant composites 1 Composite mix of materials 2 Examples a Mucus b Synovial fluid joint lubrication c Cartilage in ears nose intervertebral disks c Rigid Materials i Resist stress without much deformation ii Rigid biological materials are nearly all composites iii Examples 1 Bone 2 Keratin a Hair fingernails horn feathers 3 Wood 4 biological ceramics a dentine and enamel in teeth b mollusk shells eggshells III Stress and Strain a Stress i force applied per unit area ii Area is usually a cross sectional area iii iv Measured in N m2 Pascal or lb in2 psi 1 Psi is a unit of measurement for pressure v if the level of stress is beyond the limit the material will break b Stress i Tensile Stress tension pulling ii Compressive stress compression pushing c Strain i deformation caused by applied stress ii 1 L original length iii Dimensions 1 often put in terms of change in length 2 does not have a unit IV Stress Strain Curve a The slope of the curve is a measure of stifness i K or E stress strain ii Known as the elastic modulus b Yield Point i Up to yield point structure is in its elastic region ii Past the yield point is the structure s plastic region c Failure i If the applied force continues past the plastic region the tissure will eventually fail d Elastic Material i Linear relationship between the stress and strain ii Can be returned to original condition e Viscoelastic Material i Non linear relationship between the stress and strain ii More complex iii Hard to analyze iv Cannot be maintained after the force is applied f Stress Strain Curve g h i j k l m n o i ii In the elastic region an item will return to its original shape iii In the plastic region an item changes shape permanently Point of Failure i The point where the item breaks Strength i The load at failure Residual Strain i The diference between the original length of the material and the resting length resulting from stress into the plastic region ii The gap between original shape and the shape after the stress Safety Factor i the strength typical load e g failure stress typical stress ii Engineers usually use values 5 to 10 Energy i The energy stored put in when a stress is applied is proportional to the area under the curve ii Energy can be recovered when the stress is relieved iii Energy can be the area of the stress and strain curve underneath the slope A perfect elastic material would recover all of the energy put in A viscoelastic material only recovers a portion of the energy put in Isotropic i Isotropic materials behave the same way regardless of the direction of the applied force ii Examples glass metals Anisotropic i Anisotropic materials behave diferently when loaded from diferent directions 1 Examples wood meat bone p How can we reduce stress i Increase area ii Decrease load V Quiz a Stress is i The ration of the change in length to the resting length ii The amount of force at a particular strain iii The stored mechanical energy iv The force per unit area VI Quiz a Which is not a part of the stress strain curve i Elastic region ii Nylon region iii Yield point iv Plastic region VII Musculoskeletal System a The system of muscles and tendons and ligaments and bones and joints and associated tissues that move the body and maintain its form b Anatomy i Bones ii Ligaments iii Tendons iv Muscles v These are the most important components VIII Functions of the Skelton a Leverage b Support c Protection d Storage e Blood cell formation f means critically important for movement IX Architecture of Bone a Bone matrix of inorganic salts and collagen b Bone cells i Osteocytes transport metabolites sense mechanical stress communication ii Osteoblasts cells that create bone deposition iii Osteoclasts cells that resorb bone resorption c Osseous bone tissue i Cortical compact very dense outer layer ii Cancellous spongy very porous inner layer X Types of bone tissue a Cortical bone compact bone i Dense ii Outer layer of bones iii Made of many layers iv Stif and strong b Cancellous bone spongy bone i Porous ii Inner region of bones iii Trabeculae tiny beams 1 Adapt to direction of loading 2 Add strength without adding much weight iv High energy absorption v Not as strong as cortical bone XI Types of Bone a Long i Ulna clavicle femur b Short i Tarsals carpals c Flat i Ribs scapula sternum d Irregular i Skull vertebrae e Sesamoid i Patella XII Bone Tissue a 25 to 30 water by weight b 60 to 70 minerals and collagen i Minerals provide compressive strength and rigidity 1 Calcium and phosphate ii