KIN 3309 1st Edition Lecture 2Outline of Last Lecture I. Why Study Biomechanics?II. Basic TerminologyIII. Human Movement AnalysisIV. Areas of StudyV. Biomechanics vs. KinesiologyVI. Anatomy vs. Functional AnatomyVII. Linear vs. Angular MotionVIII. QuizIX. QuizX. Kinematics vs. Kinetics (TQ)XI. Statics vs. DynamicsXII. Skeleton – Body SegmentsXIII. Reference PositionsXIV. Relative PositionsXV. Flexion and ExtensionXVI. Abduction and AdductionXVII. Other Movement DescriptorsXVIII. Specialized Movement DescriptorsXIX. Movement Descriptors of FootXX. Pronation and Supination of the FootXXI. Reference SystemsXXII. Absolute vs. RelativeXXIII. Planes and AxesXXIV. Cardinal PlanesXXV. Degrees of FreedomXXVI. SummaryOutline of Current Lecture I. Hierarchy of StufII. Types of Solid MaterialsThese 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 StrainIV. Stress-Strain CurveV. QuizVI. QuizVII. Musculoskeletal SystemVIII. Functions of the SkeletonIX. Architecture of BoneX. Types of Bone TissueXI. Types of BoneXII. Bone TissueXIII. Ossification, Modeling and RemodelingXIV. Bone TissueXV. What would happen if the activity of bone cells was out of balance?XVI. Bones and Physical ActivityXVII. Material Properties of BoneXVIII. QuizXIX. QuizXX. Load Applied to BoneXXI. Injury?XXII. CartilageXXIII. Articular CartilageXXIV. FibrocartilageXXV. LigamentsXXVI. Stress Strain Curve for LigamentsXXVII. Synovial JointXXVIII. Types of Synovial JointsXXIX. Joint DegradationXXX. QuizXXXI. QuizXXXII. SummaryCurrent LectureI. Hierarchy of Stufa. Structural Systemb. Structurec. MaterialII. Types of Solid Materialsa. Tensile materialsi. Resist being pulled on1. (resist tensile stress)ii. Examples:1. Silk2. Collagena. Found in tendons, skin, bone, muscle and moreb. Pliant Materialsi. Must deform to function properlyii. Examples:1. Rubbers2. Elastin a. Found in skin and arterial walliii. Pliant composites1. Composite = mix of materials2. Examples:a. Mucusb. Synovial fluid (joint lubrication)c. Cartilage (in ears, nose, intervertebral disks)c. Rigid Materialsi. Resist stress without much deformationii. Rigid biological materials are nearly all composites iii. Examples1. Bone2. Keratina. Hair, fingernails, horn, feathers3. Wood4. “biological ceramics”a. dentine and enamel (in teeth)b. mollusk shells, eggshellsIII. Stress and Straina. Stress i. = force applied, per unit areaii. “Area” is usually a cross-sectional areaiii.iv. Measured in N/m2 (Pascal) or lb/in2 (psi)1. Psi is a unit of measurement for pressurev. if the level of stress is beyond the limit, the material will breakb. Stressi. Tensile Stress (“tension”): pullingii. Compressive stress (“compression”): pushingc. Straini. = deformation caused by applied stressii.1. L = original lengthiii. Dimensions1. (often put in terms of % change in length)2. does not have a unitIV. Stress-Strain Curvea. The slope of the curve is a measure of stifness:i. K or E = stress/strain =ii. Known as the elastic modulusb. Yield Pointi. Up to yield point, structure is in its elastic regionii. Past the yield point is the structure’s plastic regionc. Failurei. If the applied force continues past the plastic region, the tissure will eventually faild. Elastic Materiali. Linear relationship between the stress and strainii. Can be returned to original conditione. Viscoelastic Materiali. Non-linear relationship between the stress and strainii. More complexiii. Hard to analyzeiv. Cannot be maintained after the force is appliedf. Stress-Strain Curvei.ii. In the elastic region, an item will return to its original shapeiii. In the plastic region, an item changes shape permanentlyg. Point of Failurei. The point where the item breaksh. Strengthi. The load at failurei. Residual Straini. The diference between the original length of the material and the restinglength resulting from stress into the plastic regionii. The gap between original shape and the shape after the stressj. Safety Factori. = the strength/typical load (e.g., failure stress/typical stress)ii. Engineers usually use values 5 to 10k. Energyi. The energy stored/put in when a stress is applied is proportional to the area under the curveii. Energy can be recovered when the stress is relievediii. Energy can be the area of the stress and strain curve, underneath the slopel. A perfect elastic material would recover all of the energy put inm. A viscoelastic material only recovers a portion of the energy put inn. Isotropici. Isotropic materials behave the same way, regardless of the direction of the applied forceii. Examples: glass, metalso. Anisotropici. Anisotropic materials behave diferently when loaded from diferent directions1. Examples: wood, meat, bonep. How can we reduce stress?i. Increase areaii. Decrease loadV. Quiza. Stress isi. The ration of the change in length to the resting lengthii. The amount of force at a particular strainiii. The stored mechanical energyiv. The force per unit areaVI. Quiza. Which is not a part of the stress strain curve?i. Elastic regionii. Nylon regioniii. Yield pointiv. Plastic regionVII. Musculoskeletal Systema. “The system of muscles and tendons and ligaments and bones and joints and associated tissues that move the body and maintain its form”b. Anatomyi. Bonesii. Ligamentsiii. Tendonsiv. Musclesv. These are the most important componentsVIII. Functions of the Skeltona. Leverage*b. Support*c. Protectiond. Storagee. Blood cell formationf. * means critically important for movementIX. Architecture of Bonea. Bone: matrix of inorganic salts and collagenb. Bone cellsi. Osteocytes: transport metabolites, sense mechanical stress, communicationii. Osteoblasts: cells that create bone “deposition”iii. Osteoclasts: cells that resorb bone “resorption”c. Osseous: bone tissuei. Cortical: compact, very dense, outer layerii. Cancellous: spongy, very porous, inner layerX. Types of bone tissuea. Cortical bone (compact bone)i. Dense ii. Outer layer of bonesiii. Made of many layersiv. Stif and strongb. Cancellous bone (spongy bone)i. Porousii. Inner region of bonesiii. Trabeculae = tiny beams1. Adapt to direction of loading2. Add strength without adding much weightiv. High energy absorptionv. Not as strong as cortical boneXI. Types of Bonea. Longi. Ulna, clavicle, femurb. Shorti. Tarsals, carpalsc. Flati. Ribs, scapula, sternumd. Irregulari.