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## KNR 352: Quantitative Analysis in Biomechanics

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**KNR 352: Quantitative Analysis in Biomechanics**Dr. Steve McCaw 227B 438-3804 www.castonline.ilstu.edu/mccaw**Topics**• Basic Operations required • Dealing with vectors • Review from 282 (Basic Biomechanics) • Kinematics • Calculations of basic quantities • Displacement, velocity, acceleration • Kinetics • Calculations • GRF, CofP, JMF • Energetics • Calculations • Power, Work**Performance**Injury**Performance**Injury TASK**Task Factors**• Basic Skill • Walking • Jumping • Take off & Landing • Running • Take off & Landing • What joint actions are occurring? • What muscles are active? • What are the risks?**Task Factors**• Basic Skill • Complex Task • Throw • Assembly Task • Curl up • Hitting a baseball • What joint actions are occurring? • What muscles are active? • What are the risks?**Performance**Injury TASK Environment**Environmental Factors**• Weather/field/floor conditions • Friction====>stability, tissue loads**Environmental Factors**• Weather/field/floor conditions • Gravity • space travel & platforms**Environmental Factors**• Weather/field/floor conditions • Gravity • Open/closed task • dynamic vs. static environment**Environmental Factors**• Weather/field/floor conditions • Gravity • Open/closed task • Rules on the game/of the job • # of players • field dimensions • workplace layout • temporal constraints**Performance**Injury TASK Individual Environment**Individual Factors**• Cognitive ability**Individual Factors**• Cognitive ability • Anthropometrics**Individual Factors**• Cognitive ability • Anthropometrics • Psychological state**Individual Factors**• Cognitive ability • Anthropometrics • Psychological state • Fitness & Health • Skill level**Performance**Injury TASK Individual Environment**Performance**Injury TASK Individual Environment**Performance**Injury TASK Individual Environment Modulated by force: described by mechanics**Every structure that participates in the movement of the**body does so according to physical and physiological principles. Hamilton & Luttgens, Kinesiology: Scientific basis of Human Motion, 10th edition.**Mechanicsinfluence of force on bodies**• Biomechanics: force on biological organisms • biomechanics of fluids • circulation (lung, blood, artery)**Mechanicsinfluence of force on bodies**• Biomechanics: force on biological organisms • biomechanics of fluids • biomechanics of deformable solids • bones, ligaments, tendons**Mechanicsinfluence of force on bodies**• Biomechanics: force on biological organisms • biomechanics of fluids • biomechanics of deformable solids • biomechanics of rigid bodies • body as “rigid links” at “frictionless hinges”**Kinematics**description of pattern of motion how far how fast how consistent Kinetics Mechanics**Kinematics**description of pattern of motion how far how fast how consistent temporal aspects durations sequencing Kinetics Mechanics**Kinematics**description of pattern of motion how far how fast how consistent temporal aspects durations sequencing Kinetics study of forces that cause motion Mechanics**Kinematics**description of pattern of motion how far how fast how consistent temporal aspects durations sequencing Kinetics study of forces that cause motion magnitude direction line of action point of application Mechanics**F = m a**Force CAUSES acceleration**F = m a**Force CAUSES acceleration Force CAUSES injury**Fundamental Concepts for Biomechanical Analysis**• Units of Measure: ISU (International system of Units, ie the Metric System)**Fundamental Concepts for Biomechanical Analysis**• Units of Measure: ISU (International system of Units, ie the Metric System) • Base Units • length: meter (m) • mass: gram (g) • time: second (s)**Motion**• Change in position of a body with respect to time**Motion**• Change in position of a body with respect to time • quantify POSITION • location in 3D space: P • three reference axes: X, Y, Z • Cartesian system: axes at 90o (orthogonal)**ISB Convention: 2D**Y Progression X 0,0**ISB Convention: 3D**Vertical Y Medio-Lateral Z Anterior-Posterior X 0,0,0**Scalar quantity**described by magnitude alone mass volume distance speed Vector quantity requires description of magnitude and direction force momentum impulse displacement velocity acceleration Scalars and Vectors**Parallelogram Law forAddition of Vectors**• Sum of two vectors (resultant, R) equals the diagonal of the parallelogram with sides equal to the two vectors. • Draw on board, tail to tail • Triangle Rule: tip to tail • commutative: R = A + B = B + A • Polygon Rule: extends to 3 or more vectors**Review: Basic Trigonometry**• Right angle Triangle • naming conventions • Pythagorean Theorem • Trig functions • Sine, Cosine, Tangent (slope) • Inverse Tangent**Coordinate Systems**• Rectangular or Cartesian Coordinate System • P = Px + Py • Polar coordinate system • P = r and Ө • Polar to rectangular • (use SOH and CAH) • Rectangular to Polar • use Pythagorean Thereom and arctan Examples: P to R: 270 N @ 23 degrees R to P: Fv= 1300 N & FA/P = 100 N**Adding Force (vectors) by Summing Components**• Force: magnitude & direction need to be calculated**Adding Force (vectors) by Summing Components**• Force 1 = 50 N at -45 degrees • Force 2 = 30 N at 90 degrees Solve for Resultant**Adding Force (vectors) by Summing Components**• Force 1 = 50 N at -45 degrees • Force 2 = 30 N at 90 degrees • Force 3 = 75 N at 28 degrees • Force 4 = 15 N horizontal & 13 N vertical Solve for Resultant**New & Useful Information**Radian – the angle created by the arc on a circle with the length of the radius of the circle (~ 57.3 degrees) Arc length = 1 radius**Calculate the resultant force from Coracobrachialis and**Pectoralis Major Coracobrachialis = 1200 N, PM = 1700 N**Effect of tension development on angle of muscle insertion**and muscle activation level. Given: Muscle force = 90 N /cm2 x-sectional area X-sectional area = 4 cm2 Muscle Ө relaxed = 50° Muscle Өactive = 85°Required: 150 N force along tendon Calculate: Percentage of max muscle force developed to produce the 150 N of force.**Additional Problems**Available from web**Motion**• Change in position of a body with respect to time • quantify POSITION • quantify TIME Motion-capture systems**Motion Capture**• Pre 1985: Film • RedLake Locam: 500 fps • ~ $125 roll (film + developing) • Working in the “dark” • Record • Send for processing • Hope it all turns out ok. • All black, badly focused, missed critical event • Manual Digitizing