Knes 363 PDF

Types of Bone:1. {{c1:: Long Bones}}2. {{c1:: Short bones}}3. {{c1:: Flat}}4. {{c1:: Irregular}} Divisions of skeleton:1. {{c1:: Axial}}: {{c1:: main thoracic structure; important for protection of organs}}2.{{c1:: Appendical}}: {{c1:: limbs; for movement}} Bone marrowComponents: {{c1:: blood ve...

Types of Bone:1. {{c1:: Long Bones}}2. {{c1:: Short bones}}3. {{c1:: Flat}}4. {{c1:: Irregular}} Divisions of skeleton:1. {{c1:: Axial}}: {{c1:: main thoracic structure; important for protection of organs}}2.{{c1:: Appendical}}: {{c1:: limbs; for movement}} Bone marrowComponents: {{c1:: blood vessels, nerves and other cells}}- {{c1:: found in all bones except in the ossicles}}Function: {{c1:: generals principal cells of blood}}- {{c1:: stimulates bone formation; can lead to heterotopic ossification}}With age: {{c1:: less red marrow, more yellow marrow}} Trabecular BoneLocation: {{c1:: cuboidal, flat, and ends of long bones}}Function: {{c1:: distributes load and force throughout bones}}- {{c1:: formed through Endochondrial ossification}}Porosity: {{c1:: 75%-90%}} Cortical BoneLocation: {{c1:: shafts fo long bones, around vertebral and spongy bone}}Anatomy:1. {{c1::Osteons}}: {{c1:: circular formations}}2. {{c1:: Haversion canals}}: {{c1:: longitudinal}}3. {{c1:: Volkman canals}}: {{c1:: Horizontal channels}}4. {{c1:: Resorption cavities}}: {{c1:: temporary hollow spaces}}Porosity: {{c1:: 5-10%}}Types:1. {{c1:: Lamellar}}: {{c1:: slowly formed, highly organized}}2. {{c1:: Woven}}: {{c1:: poorly organized}}- {{c1:: Found in fracture sites, tendon/ligament attachement, bone remodelling areas}} Primary Bone: {{c1:: new bone; original bone tissue fron infancy and adolescence}}Structure: {{c1:: rings of bone growth like tree rings}}Secondary Bone: {{c1:: remodelled bone}}Structure: {{c1:: includes osteons}}- {{c1:: increased age = more osteons}} Bone Tissue Composition1. {{c1:: 43% HA}}2. {{c1:: 32% Collagen/organic}}3. {{c1:: 25% Water}}Measures:1. {{c1:: Bone volume fraction and porosity}}: {{c1:: not indicative of percent composition of matrix (e.g. collagen)}}Formulas: - {{c1:: fraction = hard bone matrix volume/ (hard bone matrix volume+soft tissue volume)}}- {{c1:: porosity (Pv)= soft tissue volume/ (hard bone matrix volume+soft tissue volume)}}Ranges: - Trabecular: {{c1:: Pv> 0.5}}- Cortical: {{c1:: Pv<0.5}}2. {{c1:: Bone Apparent Density}}:Formula: {{c1:: (soft tissue mass + hard tissue mass)/(hard bone matrix volume+soft tissue volume)}}3. {{c1:: Bone ash fraction}}: {{c1:: mineralization of bone tissue independent of porosity - no void space}}Components:- {{c1:: Dry mass - no water}}: {{c1:: md= organic matrix mass/mineral mass}}- {{c1:: Ash mass - no collagen}}: {{c1:: ma= mineral mass}}Formula: {{c1:: ma/md}}Range: {{c1:: near 0.65}} Osteoclasts: {{c1:: similar to macrophages - cleave bone}}Anatomy: {{c1:: multinucleated formed in bone marrow}}Functioning: {{c1:: move fast}}1. {{c1:: Demineralize bone with acids}}2. {{c1:: Dissolving collagen}} Osteoblasts: {{c1:: similar to fibroblasts and build bone}}Structure: {{c1:: mononuclear made from mesenchymal stem cells}}Functioning: {{c1:: lays down osteoid (organic portion) very slowly}} Osteocytes: {{c1:: osteoblasts that were trapped in lacunae}}- {{c1:: most abundant cell in bone}}Functioning: {{c1:: Plays a role in mechanosensation}} - {{c1:: communicate via dendritic processes (canniculi)}} Bone Lining Cell: {{c1:: osteoblasts that escaped lacunae and are on the surface of bone and become quiescent}} Bone Modelling: {{c1:: osteocytes and osteoblasts work seperately in different areas}}Function: {{c1:: changes in bone size and shape}}Over time: {{c1:: increases most in development; impacted by P.A. during childhood}} Bone Remodelling: {{c1:: coupled actions of osteoblasts and osteoclasts in the same spot}}Function: {{c1:: removes old bone and replaces with new bone}}- {{c1:: no change in size or shape}}- {{c1:: effieicent way to extract calcium}}Time: {{c1:: decreases after growth}} Axial/normal Stress: {{c1:: perpendicular to the surface; compressive/tensile}}Normal plane formula: {{c1:: F/A}}Incline plane formula: {{c1:: F/A cos^2 theta}}Shear Stress: {{c1:: parallel to the surface area}}Incline plane formula: {{c1:: -P/A sin theta cos theta}} Principal Stress: {{c1:: maximum normal stress, and no shear stress}}- {{c1:: 90 degrees apart}}- {{c1:: max shear at 45 degrees between principal stresses}}Failure:1. {{c1:: In ternsion/stretching = max principal}}2. {{c1:: Shear failure= max shear stress with compression}}3. {{c1:: Pure shear failure at 45}}: {{c1:: torque?}} Strain: {{c1:: deformation; has two dimensions}}Axial: {{c1:: change in length in the normal/original length in the normal}}- {{c1:: causes size change}}Shear: {{c1:: change in length in the shear/ original length in normal}}Also: {{c1:: tan theta (in radians)}}- {{c1:: causes shape change}} Principal Strain: {{c1:: no shear strain, max normal strain}} "Poisson's Ratio: {{c1::material loaded in one direction is deformed in both directions}}Formula: {{c1:: transverse strain/axial strain}}" Hookes Law: Formula: {{c1:: E= stress/strain}} OR {{c1:: E*change in length/original length}}- {{c1:: Material property}} StiffnessFormula: {{c1::F/displacement}} OR {{c1:: EA/original length}}- {{c1::structural property; depends in size, material, etc.}} Toughness: {{c1:: area under the curve}}- {{c1:: amount of energy bone can absorb before failure}} Stress Strain Graphs1. {{c1:: Yeild strenght}}: {{c1:: no longer linear; able to go back to zero strain with zero stress}}2. {{c1:: Ultimate Strength}}: {{c1:: max stress before failure}}3. {{c1:: Failure}}: {{c1:: point of fracture}}4. {{c1:: Toughness}}: {{c1:: total energy that can be absorbed}} Toughness vs Strength1. {{c1:: Strength}}: {{c1:: amount of load the material can withstand}}- {{c1:: ultimate stress}}- {{c1:: bone = strong}}2. {{c1::Toughness}}: {{c1:: amount of load/stress that can be absorbed}}- {{c1:: area under stress-strain curve}} Material Property: Affected by:1. {{c1:: Loading mode}}2. {{c1:: Direction}} Bone Directional Dependence1. {{c1:: Isotropic}}: {{c1:: there is no direction dependence; stress/strain is same everywhere}}2. {{c1:: Anistropic}}: {{c1:: there is directional dependence}}- {{c1:: Transverse}}: {{c1:: two planes that are parllel to the osteons have no difference in stress/strain,  but one plane is different}}     e.g. {{c1:: cortical bone}}- {{c1:: Orthoropic}}: {{c1:: all planes are different}}    e.g. {{c1:: trabecular/cartilage}} Elastic Deformation: {{c1:: strain is zero when stress is zero}}Plastic Deformation: {{c1:: when stress is zero, strain does not go back down}} Stress-Strain: Trabecular vs CorticalCortical:- {{c1:: high ultimate stress point}}- {{c1:: low yeild strain}}- {{c1:: steep, strong and brittle}}Trabecular:- {{c1:: low ultimate stress point}}- {{c1:: High Yeild point}}- {{c1::tough and weak}} Measuring Mechanical Properties Invasive: {{c1:: test to failure}}Non-invasive: {{c1:: ultrasound}}- Benefits: {{c1:: repeat tests on all axes}} Density -Elasticity Relationship: {{c1:: higher density=higher elastic modulus}} Mechanical Properties Factors 1. {{c1:: Sample orientation}}: {{c1:: strongest parallel to osteons}}- {{c1:: strongest in the longitudinal than transverse}}2. {{c1:: Sample hydration}}- {{c1:: water=increased toughness and elasticity}}3. {{c1:: Strain rate}}- {{c1:: faster=stronger and brittle due to viscoelasticity}}4. {{c1:: Loading mode}}- {{c1:: cortical bone is very different (strongest in compression, then tension and shear}}- {{c1:: trabecular bone is very similar in compression and tension}} Viscoelasticity: {{c1:: deformation is dependent on rate}}- {{c1:: bone is very slightly viscoelastic}} Bone Strength Dependant on:1. {{c1:: Density}}: {{c1:: most important}}- {{c1:: higher density=stronger}}2. {{c1:: Fabric/orientation}} Bone Relationships 1. Density and modulus: {{c1:: increased density=increased modulus}}- {{c1:: variations are due to fabric}}2. Yield Stress and modulus: {{c1:: increased modulus=increased yield stress point}}3. Yeild stress/modulus and yeild strain: {{c1:: not effected}}Meaning: {{c1:: fracture and yeilding is dependent on strain not stress}} Toughening of Bone after Yeild point: {{c1:: to allow for more strain to occur before failure}}1. {{c1:: Crack bridging by collagen}}: {{c1:: collagen fibres seperate and connect to distribute load}}2. {{c1:: Crack bridging by uncracked ligaments}}: {{c1:: minerals form bridges to distribute load}}3. {{c1:: Microcracks}}: {{c1:: absborbs more of the energy}} Beam TheoryAssumptions:1. {{c1:: Constant cross sectional geometry}}2. {{c1:: Longitudinal plane of symmetry}}3. {{c1:: Homogenous material}}Steps:1. {{c1:: Resolve forces and moments by assuming static equilibrium}} Axial Loading: {{c1:: uniform normal force on every section of loaded tissue}}Stress: {{c1:: F/A}}Strain: {{c1:: change in length/original length OR F/AE}} Tensile stress is {{c1:: positive}} and compressive stress is {{c1:: negative}} Shear Loading: {{c1:: parallel to surface loading}}Stress: {{c1:: Parallell force/cross sectional area}}Strain: {{c1:: radian/length OR shear force/AG}}SignPositive face: {{c1:: normal force is in the positive axis}}Negative face: {{c1:: normal face in the negative axis}}Positive shear: {{c1:: force acts in the positive direction on the negative face}}Negative shear: {{c1::  force acts in the negative direction on the positive face}} Bending: {{c1:: tension and bending combined}}Principles:1. {{c1::  Gradient force, where middle in neutral}}Stress: {{c1:: Mx/I}} where {{c1:: x= distance from neutral axis}} and {{c1:: I = pi/4 (r2-r1)^4}}Strain: {{c1::Mx/EI}}Overall stress= {{c1:: axial stress + stress due to bending}} "" Types of Cartilage1. {{c1:: Hyaline/articular}}: {{c1:: most prevalant in adults; covers joint surfaces}}2. {{c1:: Elastic}}: {{c1:: in the external ear, eustachian tubes, and epiglottis; mainly for form (flexible)}}3. {{c1:: Fibrocartilage}}: {{c1:: in intervertebral disks, meniscus, tendon-bone attachement, and replaces hyaline cartilage when damaged}} Articular Cartilage Composition1. {{c1:: ECM}}: {{c1:: made via chondrocytes which are metabolically active and in lacuna (not connections tho)}}Function: {{c1:: mechanical properties}}Components:i) {{c1:: 20-35% collagen + proteoglycans}}ii) {{c1::65-80% water}}2. {{c1:: No blood or nerve supply}} ChondrocytesComposition: {{c1:: <5% of tissue}}- {{c1:: surrounded by chondron}}Function: {{c1:: sythesize and degrade ECM; gets nutritions from synovial fluid via mechanical compression}} Cartilage CollagenComposition: {{c1:: 50% of solid matrix}}Type: {{c1:: II}}Form: {{c1:: fibrillar network}}Properities: {{c1:: high tensile strength and stiffness, influences permeability}} Proteoglycans - CartilageComposition: {{c1:: 30% of dry weight}}Properties1. {{c1:: Form aggregates}}2. {{c1:: Negative charge causes repulsion from each other and attraction to water}}3. {{c1:: High compressive strength}} PG + Collagen: {{c1:: PG attached to collagen fibrillar network which is then filled with water}} Collage StructureProperties:1. {{c1:: Non-homogenous}}2. {{c1:: Variations depth wise (content, orientation, shape and size)}}Zones:1. {{c1:: Superficial}}Composition: {{c1:: 10-20% of cartilage}}- {{c1:: Lowest PG content}}Form: {{c1:: Collagen and chondrocytes (flat) are parallel to surface}}2. {{c1:: Middle}}Composition: {{c1:: 40-60% of cartilage}}- {{c1:: highest proteoglycan; traps the most water = most important for resisting load}}Form: {{c1:: randomly arranged chondrocytes and collagen}}3. {{c1:: Deep}}Composition: {{c1:: 30% of cartilage}}Form: {{c1:: Chondrocytes and collage perpendicular to surface}}4. {{c1:: Calcified}}: {{c1:: transitional zone between bone and cartilage; denoted by a tidemark}} Cartialge Functions1. {{c1:: Lower joint stress via stress distribution}}2. {{c1:: Reduce friction (main one)}}**{{c1:: not shock absorption}}** Collagen Mechanical Properties1. {{c1:: Inhomogenous}}- {{c1:: depth dependant modulus: deeper = higher stiffness (E)}}2. {{c1:: Biphasic (fluid and solid)}}- {{c1:: cartilage is porous permeable fluid filled material}}3. {{c1:: Viscoelastic}}Demonstrates:I) {{c1:: Creep}}II) {{c1:: Stress relaxation}}III) {{c1:: Effective stiffness being load dependent}}IV) {{c1:: Hysteresis}}V) {{c1:: Energy loss with impact}}4. {{c1:: Anisotropic}} Creep: {{c1:: when constant stress/load is applied strain slowly increases over time}} Stress Relaxation: {{c1:: with constant strain/deformation, bone slowly decreases in stress}}Mechanism:1. {{c1::Rise of stress}}: {{c1:: fluid efflux}}2. {{c1:: Relaxation}}: {{c1:: matrix redistribution}}3. {{c1:: Equilibrium}}: {{c1:: external load=internal resistance}} Cartilage Viscoelasticity1. Loading:- {{c1::: fluidng is escaping causing cartilage to compact}}- {{c1:: load is borne by fluid}}- {{c1:: shows a dynamic modulus that is time dependent}}2. Equilibrium: {{c1:: Fluid flow stops}}- {{c1:: solid bears weight}}- {{c1:: equilibrium modulus}} Cartilage - Strain Rate Dependence: {{c1:: faster rate= more stiff as water cannot escape fast enough}} Cartilage Permeability: {{c1:: increased load decreases pore diameter; increased strain = decreased permeability + stiffness}} Cartilage - Strain Rate + Permeability: {{c1:: faster strain rate=decreased diameter of pores=more resistant/stiff and less permeable}} Cartilage Tensile LoadingModulus= {{c1::3-10 MPa}}Graph:1. {{c1:: Toe region}}: {{c1:: flat region where the collagen fibres are reorienting and not carrying load}}Tensile properties:1. {{c1:: anisotropic}}2. {{c1:: parallel strenth is the greatest}}3. {{c1:: collagen fibres realign when loaded}}4. {{c1:: lower tensile strength in cartilage than tendon}} Tendon Function: {{c1:: force transmission from muscle to bone}}Composition:1. Extracellular  {{c1::80%}}:- {{c1:: 55-70% water}}- {{c1:: 65% collagen - mainly type I}}- {{c1:: 2% elastin}}- {{c1:: 1% proteoglycans}}2. Cellular: {{c1:: 20% - all are tenocytes}} Tenocytes: {{c1::mechanoreceptors for tendon loading}} Free Tendon StructureGeneral: {{c1:: hierarchal structure (collagen firbils > fibre> bundle)}}- {{c1:: contains a weak fibre which provides alternate paths of stress decreasing the change of complete failure of tendon}}- {{c1:: easier to repair}}Regions:1. {{c1:: External/free tendon}}: {{c1:: most older tendon injuries}}2. {{c1:: Aponeurosis/internal tendon at the myotendinous juction}}3. {{c1:: Osteotendinois junction}}: {{c1:: younger tendon injuries}} Myotendinous JunctionProperties: {{c1:: folding pattern which increases surface area}}- {{c1:: increases stability and decreases stress}}- {{c1:: turns tension into shear which the tendon can handle better}}Includes: {{c1:: GTOs which are mechanoreceptors for muscle tension}} Osteotendinous JunctionProperties: {{c1:: gradual transition from tendon to bone}}{{c1:: tendon > fibrocartilage> mineralized fibrocartilage>bone}} "Viscoelasticity- TendonViscous properties: {{c1:: fluid resistance to flow}}Elastic properties: {{c1:: return to original shape via collagen, crimp, elastin}}Properties1. {{c1:: Rate dependent}}: {{c1:: high rate = increased ultimate tensile stress/strain, young's modulus}}2. {{c1:: Hystersis}}: {{c1:: energy loss (area between curve) when loading decreases due to heat, and disruption of cross-links}}3. {{c1:: Stress-relaxation}}: {{c1:: constant deformation=decreased stress with time}}4. {{c1:: Creep}}: {{c1:: constant force=increased deformation (occurs in cyclic loading as well)}}"  Tendon - Creep Stiffness Degradation{{c1::With repeated loading cycles due to creep}}:1. {{c1:: Deformation increases with each}}2. {{c1:: Stiffness decreases with each}}3. {{c1:: Decreasedd modulus with each}}4. {{c1:: Steady after 10-20 cycles}}Post-exercise: {{c1:: decreased tendon stiffness + increasing stretch}}Residual Strain: {{c1:: decreasing slope and increased relaxed strain due to high plastic deformation}} Tendon - Fatigue Life: {{c1:: number of submaximal stress/strain before failure, below ultimate stress}}Pattern progression:1. {{c1:: Unloaded crimped fibres}}2. {{c1:: load cayses stretching into plastic region}}3. {{c1:: fibre kinks}}4. {{c1:: Damage = less fibres to carry load = increased strain and stress}}- {{c1:: positive feedback mechanism in stress injuries}}Properties:1. {{c1:: Sensitive to stress magnitude}}2. {{c1:: Small increases in stress = non-linear decrease in cycles to failure}} ARF: {{c1:: Bone remodeliing}}1. {{c1::Activation}}: {{c1:: differentiation of precursor cells into osteoclasts. This process takes approximately 3 days}}2. {{c1::Resorption}}: {{c1:: osteoclasts break down the existing bone matrix. The resorption phase has an estimated duration of 30 days}}3. {{c1::Formation}}: {{c1:: Osteoblasts  synthesize new bone matrix, known as osteoid. Takes 3 months}}4. {{c1::Full Mineralization}}: {{c1::  synthesized bone matrix undergoes a mineralization process, which takes an additional 6 months to reach completion}}The entire A-R-F cycle can take up to {{c1::9 months}}Functions of the A-R-F Sequence1. {{c1:: Removal of Damaged Bone}}2. {{c1::Calcium Homeostasis}}3. {{c1::Mechanical Adaptation}} Types of Muscle1. {{c1:: Smooth}}: {{c1:: Found in lining}}- {{c1:: Involuntary}}2. {{c1:: Cardiac}}: {{c1:: striated}}- {{c1:: Involuntary}}3. {{c1:: Skeletal}}- {{c1:: locomotion; active force}} Muscle Functions- {{c1:: Movement}}- {{c1:: joint stablity}}- {{c1:: passive force transmission}} Muscle Organization:{{c1:: Muscle}}>{{c1:: fascile}}> {{c1:: Fibre (multinucleated)}}> {{c1::fibril}} Sarcomere: {{c1:: z to z line}}Components:1. {{c1:: Mysoin}}: {{c1:: thick}}- {{c1:: spiral orientation of heads}}2. {{c1:: Actin}}: {{c1:: thin}}- {{c1:: line of G-acting, covered by tropomyosin and troponin}}Sections:1. {{c1:: I band}}: {{c1:: actin only - shortens}}2. {{c1:: H zone}}: {{c1:: myosin only - shortens}}3. {{c1:: A band}}: {{c1:: actin and myosin - stays the same}} Muscle Contraction:Anatomy1. {{c1:: Motor neurons}}2. {{c1:: Motor unit}}: {{c1:: MU + all fibres innvervated}}Control:1. {{c1:: Motor unit size}}2. {{c1:: Number of fibres}}3. {{c1:: Distribution of fibres}}4. {{c1:: Type of fibres}}Steps:1. {{c1:: AP (50 mV) reaches pre-synaptic terminal}}2. {{c1::ACh is released}}3. {{c1:: Binds to NMJ > sodium in}}4. {{c1:: AP travels down T-tubules to sarcollema > Calcium release}}5. {{c1:: Calcium pulls on troponin, pulling tropomyosin off of actin}}6. {{c1:: ATP attachs to myosin and is hydrolyzed, causes myosin to attach and move actin}}7. {{c1:: ATP dettaches causing myosin to let go}} Muscle ArchitectureFibre Orientation Categories:1. {{c1:: Fusiform}}: {{c1:: parallel to force generating axis}}2. {{c1:: Unipennate}}: {{c1:: fibres at single angle to axis}}3. {{c1:: Multipennate}}: {{c1:: multiple diff angles}}Pennation: {{c1:: angle between fibre and line of pull}}- Formula: {{c1:: Force tendon=fibre force cos (angle btwn tendon + fibre)}}Areas:1. {{c1:: Cross sectional}}: {{c1:: geometrical cross section, across belly of muscle}}2. {{c1:: PCSA}}: {{c1:: area based on orientation of muscle fibres}}- {{c1:: determines force more}}Length vs Thickness: {{c1:: if same volume same work}}1. {{c1:: Long + thin }}: {{c1:: greater ROM}}2. {{c1:: Short + thick}}: {{c1:: stronger/faster force production}} Motor Unithigh fibre count = {{c1:: explosive/dynamic}}small fibre count = {{c1:: fine control}}many motor units = {{c1:: finer control}}less motor units= {{c1:: less activation needed for more force}} Twitch ContractionParts:1. {{c1:: Latent period}}: {{c1:: ~5ms; time required to generate force after AP}}2. {{c1:: Contraction}}: {{c1:: ~20 ms; time to generate peak force}}3. {{c1:: Relaxation}}: {{c1:: ~70+ ms; time to relax muscle}} Fibre Types1. {{c1:: Type 1}}: {{c1:: slow twitch}}- {{c1:: oxidative}}- {{c1:: fatigue resistance}}- {{c1:: slow ATPase}}- {{c1:: endurance}}2. {{c1:: Type IIa}}: {{c1:: Fast fatigue resistance }}- {{c1:: oxidative + glycolytic}}- {{c1:: fast twitch}}- {{c1:: fast ATPase}}3. {{c1:: Type IIb}}: {{c1:: Fast  fatigable}}- {{c1:: glycolytic}}- {{c1:: fast}}Distribution: {{c1:: mix of all; number affects muscle overall}}- {{c1:: can be altered through training}} Control of Muscle Contraction1. {{c1:: Temporal Summation}}: {{c1:: multiple APs at the same time}}2. {{c1:: Spatial summation}}: {{c1:: mutiple APS to the same spot}}Principle: {{c1:: Hennmans size principle}}- {{c1:: small > large MU recruitment | large > small derecruitment}} Muscle Sensory Organs1. {{c1:: Spindles}}: {{c1:: parallel in muscle; stretch}}2. {{c1:: GTO}}: {{c1:: MTJ; muscle tension}} Sliding Filament Theory: {{c1:: by Huxkey}}- {{c1:: muscle shortening via movement of filaments past each other (cross bridges)}} Active Force Production: {{c1:: force made by cross-bridging and ATP}}F-L Regions:1. {{c1:: Ascending limb}}: {{c1:: partial - complete overlap of thin filaments}}- {{c1:: Compression of thick filaments}}- {{c1:: little to building force}}2. {{c1:: Plateau}}: {{c1:: inclusion and exclusion of H zone; no overlap of filament by itself}}- {{c1:: highest force produced}}3. {{c1:: Descending limb}}: {{c1:: filaments are being pulled farther away from each other}}- {{c1:: decreasing force production}}Factors1. {{c1:: Temporal + Spatial Summation}}2. {{c1:: CSA}}- {{c1:: larger CSA/fibres in parallel=more force}}3. {{c1:: Muscle Architecture}}- {{c1:: longer=higher ROM}}4. {{c1:: Cross bridges}} Passive Force: {{c1:: no cross bridges, connective tissue force}}Tests:1. {{c1:: Release test}}: {{c1:: exhibits hysteresis}}2. {{c1:: Stress relaxation}}: {{c1:: decrease in force over time}}3. {{c1:: Creep}}: {{c1:: increasing strain over time}}Structures:1. {{c1:: Connective tissue}}: {{c1:: does not produce passive force}}- {{c1:: Fascia}}- {{c1:: Endomysium}}- {{c1:: Perimysium}}2. {{c1:: Intra-fibre}}- {{c1:: Titin}}: {{c1:: links neighbour  Z lines}}    > {{c1:: largest protein; molecular spring}}    > {{c1:: bears most of passive force}}    > {{c1:: No titin = no passive force production}}- {{c1:: Desmin}}: {{c1:: intermediate filaments for longitudinal and 3D scaffold between Z lines}}    > {{c1:: connects contractile portion to sarcolemma and proteins}} Active + Passive FL:Movement: {{c1:: active force increases inverted U, when active force is zero, passive force rises}}- {{c1:: can change based on training; bikers = stronger at short length, runners=stronger at longer lengths}} F-V Relationship - General: {{c1:: increased speed =decreased force; increased energy use}}Experiments:1. {{c1:: Fenn+Marsh}}: {{c1:: animal model; force decrease with speed}}2. {{c1:: Hill}}: {{c1:: when working on heat production in frog muscle}}CSA:1. {{c1:: Large PCSA}}: {{c1:: higher max and average force}}2. {{c1:: Small}}: {{c1:: smaler force level, but same max velocity}} F-V Isotonic Relationship: {{c1:: constant force production}}Findings: {{c1:: increasing force=decreased velocity}}}}Isokinetic: {{c1:: constant velocity}}Findings: {{c1:: increasing velocity (independent) decreases force}} Muscle Shortening: {{c1:: concentric contraction}}Graph: {{c1:: Hyperbolic}}- {{c1:: Max force at zero velocity}}- {{c1:: increasing velocity=decreasing force (rapid drop initially)}}Formula: {{c1:: Hills equation}}- {{c1:: (F+a (force constant))V= b(speed constant) (Fmax=F)}}Fibre types: {{c1:: both ST + FT will have same max force, FT will just perform at higher velocities than ST}} Muscle Lengthening: {{c1:: eccentric contractions}}Graph: {{c1:: force is independent of velocity}}Importance:- {{c1:: greater muscle strength}}- {{c1:: most of activity}}- {{c1:: muscle inury and soreness}} "FV RelationshipShortening Contractions:Principles: {{c1:: force depends on number of cross bridges + force per cross bridge}}1. {{c1:: increased velocity = decreased crossbridge}}- {{c1:: less time for crossbridge attachement}}2. {{c1:: Increased velocity = decreased cross bridge force}} - {{c1:: contraction = less spring tension}}Lengthening ContractionsPrinciples:1. {{c1:: Attached cross bridges are pulled due to spring stretch = increased force per cross bridge}}2. {{c1:: Cross bridges don't dettach = no force decrease}}" Power - Velocity Relationship - General: {{c1:: increasing power = decreasing power}}- {{c1:: max power at 1/3 of Vmax}}Fibre types: {{c1:: FT will have hight power than ST (since higher force/time)}} Increasing Force Via: 1. {{c1:: increased force}}2. {{c1:: moment arm}}3. {{c1:: increasing joint angle (increases moment arm)}} Muscle Relationships in Vivo1. {{c1:: Moment-angle instead of F-L}}: {{c1:: increased angle = increased moment}}Compared to {{c1:: F-L}}- {{c1:: smoother}}- {{c1:: large plateau}}- {{c1::complex}}- {{c1:: length via ultrasound - nonunfiromitiies = diff force generation in vivo}}2. {{c1:: moment angular velocity instead of F-V}}Comparison:- {{c1:: FV=hyperbolic, M-A= negatively linear (increased velocity=decreasedmoment)}}- {{c1:: in vivo= different moment arms due to crossbridges in joint, pennation angle, and non-uniform force distribution}}3. {{c1:: Power -angular velocity instead of P-V}}Comparison: {{c1:: similar, less steep}} Plasticity + Strength Training: {{c1:: training =more force}}Strength: {{c1:: maximal isometric torque at specific angle}}Experiment:  {{c1:: Ericson}}Findings: {{c1:: training = increased fibre diameter + more force}}Causes:1. {{c1:: greater crosssectional area}}- {{c1:: increase in muscle size}}- {{c1:: increased fibre in parallel}}- Cause: {{c1:: satellite cell activation}} = {{c1:: proliferation > differentation of myoblasts to myofibrils}}2. {{c1:: more force per CSA}}- {{c1:: neural adaptations}}: {{c1:: temporal and spatial summation}}- {{c1:: muscle architectre}}: {{c1:: fibre type change, pennation angle}} Strength Training1. Initial improvements: {{c1:: 1-2 weeks}}Cause: {{c1:: coordination}}2. Middle improvements: {{c1:: 3-4 weeks}}Cause: {{c1:: neural adaptations}}3. Late improvement: {{c1:: 4+ weeks}}Cause: {{c1:: muscle hypertrophy}} Plasticity + Endurance TrainingChanges:1. {{c1:: Increased Type 1 fibres}}2. {{c1:: increase mitochondria}}3. {{c1:: increased vascularization + oxygen delivery}} Training: {{c1:: adaptation is specific to position and muscle trained}} Plasticity + Decreased Demand1. {{c1:: Disuse}}: {{c1:: neuromuscle disease, spinal cord injury, denervation, immobilization, space flight}}Results:- {{c1:: decrease in muscle mass; a lot in load bearing}}- {{c1:: less type II size}}- {{c1:: decreased protein synthesis}}- {{c1:: decreased thin filament density = contracts faster but not whole muscle}}2. {{c1:: Aging}}: {{c1:: sarcopenia}}Results:- {{c1:: decreased CSA}}- {{c1:: decreased fibre size and number (esp fast twitch)}}- {{c1:: decrease MU size and number}}- {{c1:: decreased MU synch}}- {{c1:: decreased number and diameter of motor axons}}  JointDefinition: {{c1:: joining f two or more bones}}Structure Classifications1. {{c1:: Fibrous}}: {{c1:: connective tissue; stability}}- {{c1:: Sutures}}- {{c1:: Syndesmoses}}: {{c1:: R/U}}- {{c1:: Gomphosese}}: {{c1:: tooth/jaw}}2. {{c1:: Cartilaginous}}: {{c1:: sock absorbtion}}- {{c1:: syncondorses}}: {{c1:: hyaline - sternocostal}}- {{c1:: Symphyses}}: {{c1:: fibrocartilage - intervertebral disks}}3. {{c1:: Synovial}}: {{c1:: highly movement}}- {{c1:: indludes synovial fluid (water, HA, and lubricin)}}: {{c1:: lubrication, shock absorption, nutrient supply}}Function Classifications1. {{c1:: Synarthrosis}}: {{c1:: immovable}}2. {{c1:: Amphiarthrosis}}: {{c1:: limited movement}}3. {{c1:: Diarthrosis}}: {{c1:: freely movable}} Joint Functional Classifications1. {{c1:: Pivot}}: {{c1:: rotation}}2. {{c1:: Gliding}} e.g. {{c1:: hand}}3. {{c1:: Ball and Socket}}4. {{c1:: Hinge}}: {{c1:: knee}}5. {{c1:: Saddle}}: {{c1:: thumb}}6. {{c1:: Condyloid}}: {{c1:: wrist}} Planes of Motion1. {{c1:: Sagittal plane}}: {{c1::  rotation about x-axis}}Movement: {{c1:: flexion + extension}}2. {{c1:: Frontal plane}}: {{c1:: rotation about y axis}}Movement: {{c1:: abduction and adduction}3. {{c1:: Transverse plane}}: {{c1:: rotation about z axis}}Movement: {{c1:: rotation}} Degrees of Freedom: {{c1:: number of ways to move in space; all joints have all 6 degrees, but should not always move in all 6}}Rotational1. {{c1:: flexion/extension - rotation about x}}2. {{c1:: Abduction/adduction - rotation about y}}3. {{c1:: internal/external rotation - rotation about z}}Translational1. {{c1:: medial/lateral - about x}}2. {{c1:: anterior/posterior - about y}}3. {{c1:: superior/inferior - aout z}}Application1. {{c1:: Understand common joint movements}}2. {{c1:: Understanding mobility/mobility trade-off}}3. {{c1:: impact on sports performance}}4. {{c1:: Injury prevention}} CSB: {{c1:: anatomical position is zero degrees}}Segment: {{c1:: absolute}}Joint: {{c1:: relative}}Formula: {{c1:: angle= Q +arctan y/x}}- {{c1:: Q1 = 0, Q2 = 180, Q3= 180, Q4=360}} Goal of Surgery1. {{c1:: restoration of function}}2. {{c1:: pain reduction}}Mechanisms:- {{c1:: abbrading cartilage to make fibrocartilage}}- {{c1:: replacement}}- {{c1:: fusion of joint}}3. {{c1:: improve quality of life}}4. {{c1:: structural integrity}} Athroscopy: {{c1:: minimally invasice surgical technique using maera}} Reconstruction/grafts: {{c1:: replacement of ligament in severe ligament damage}}Types:1. {{c1:: Autografts}}: {{c1:: patients tissue}}2. {{c1:: Allografts}}: {{c1:: donor tissue}} Ligament RepairTechniques:1. {{c1:: Primary}}: {{c1:: suturing}}2. {{c1:: Augmentation}}: {{c1:: reinforcement}}Cartilage RepairTechniques:1. {{c1:: Microfracture}}: {{c1:: drilling to stimulate cartilage growht}}2. {{c1:: Chondrocyte implantation}}3. {{c1:: Grafts}} "Joint ReplacementsCommon:1. {{c1::Hip}}2. {{c1:: Knee}}3. {{c1:: Shoulder}}Causes:1. {{c1:: pain + unresponsive to treatment}}2. {{c1:: Deformitity/functional limitations}}3. {{c1:: joint damage}}Materials used:1. {{c1:: Metals}}: {{c1:: cobtal, titatnium}}2. {{c1:: Polymers}}3. {{c1:: Ceramics}}: {{c1:: biocompatiblity}}Features:1. {{c1:: Allows for natural movement + some degree of flexion and movement}2. {{c1:: Stress Shielding}}: {{c1:: not super stiff implant otherwise the mechanical stress won't be distributed to bone, and the bone around the implant will be resorbed and then become loose}}"