KINE 3030 Notes - All important concepts in Kine 3030. PDF

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KINE 3030 Biomechanics of Human MovementChapter 1 – What is BiomechanicsLecture 1 Biomechanics – studying biological systems from a mechanical perspective o Uses the tools of mechanics, the branch of physics involving he analysis of the action of force to study the anatomical and functional aspects ...

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KINE 3030 Biomechanics of Human Movement Chapter 1 – What is Biomechanics Lecture 1 -

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Biomechanics – studying biological systems from a mechanical perspective o Uses the tools of mechanics, the branch of physics involving he analysis of the action of force to study the anatomical and functional aspects of living organisms o Study of the effects and control of the forces that act on and are producing by bodies  Comes down to pushes and pulls, somehow they makes us moves in certain directions ending up with certain velocities, accelerations, creating movement  Understanding how these forces are acting on us and how they are controlled (neurocontrol) gives us an idea of how we are going to move  The effects are movement or non movement Why we Study Biomechanics – helps address problems in human health and performance o Ex) researchers, ergonomists, phys ed teachers, physio’s, physicians, coaches, personal trainers etc. Problems Studied in Biomechanics – Locomotion patterns, mobility impairment … etc o Clinical/occupational research, sport performance enhancement, safety and injury reduction

Biomechanics - biology + physics - Biology o Anatomy physiology o Bone, muscle, ligaments, joints o Musculoskeletal system - Physics o Motion  Angular/linear  Displacement, velocity, acceleration  Force, impulse, momentum, work, power - Subfields o Mechanics – physical science which deals with state of rest or motion of a body under forces  Statics – equilibrium of bodies under the action of forces (no motion)  Things that don’t move  Constant velocity  Dynamics – there is acceleration  Kinematics, kinetics  Velocities, changing velocities  Kinematics – description of motion  Kinetics – forces, torques, and movements, that actually create the movement Lecture 2 Dynamics - Newton’s Second Law – F = m a o Force = Mass x Acceleration - Kinetics – forces that cause motion ex) force o External forces o Internal forces ex) muscle

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o Relates the forces acting on bodies to resulting motion o Joint anatomy o Neural control Inertia – resistance to motion ex) mass o Anthropometry – how our weight is distributed, mass depends on this  Mass  distribution Kinematics – motion o Acceleration is Motion o Study of the motion of bodies with out reference to forces that cause the motion  The movements we make whether elite or pathological it cause from the cause of kinetics The right side of this equation is kinetics, the acceleration is kinematics Kinetics is the cause kinematics is the effect

3 General Areas of Study - 1. Describing movement and how it is produced o ex) Human gait, sport performance, robotics, functional anatomy etc - 2. Assessing how tissues are injured and how injuries can be prevented o tissue loading  advanced biomechanics o osteoarthritis o prosthetic implants  clinical biomechanics o protective equipment o occupation injuries  occupation biomechanics o forensic biomechanics - 3. Determining how performance can be optimized o ex) sports performance and training, occupational production, therapy, F.E.S., tendon transfer, prosthetic and orthotics o human movement analysis can be approached from both a qualitative and quantitative perspective o Qualitative ex) good, poor, long heavy, etc. o Quantitative ex) six meters, 3 seconds, 25 degrees Anatomical Foundations - Frontal Plane – the front view of the body - Sagittal Plane – the side view of the body - Horizontal/Transverse Plane – viewing the body form a birds eye view ex) spinning motion - The plane we move in the most is a sagittal - Many of human activities are multi-planar, ex) serving a tennis ball - Superior- towards head - Inferior – towards feet - Anterior – towards front - Posterior – towards back - Medial – towards center - Lateral – towards the outside - Proximal – closer to the center for your arm or leg - Distal – closer to the end of a limb - Superficial – closer to the surface of the body

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Deep – deeper in the surface of the body

Movement Terms - Flexion – mostly done in the sagittal plane o Decreasing the joint angle o Knee flexion is opposite - Extension – mostly done in sagittal plane o Increasing the joint angle o knee extension is opposite - Dorsiflexion – movement of the top surface of the foot towards the front of the leg - Plantar flexion – movement of the plantar surface of the foot to the back of the leg - Abduction – away from the midline - Adduction – towards the midline - Medial Rotation (Pronation) – medially rotating a limb ex) radius over he ulna - Lateral rotation – laterally rotating the limb ex) ulna over the radius - Eversion – movement of the plantar surface of the foot laterally outward - Inversion – movement of the plantar surface of the foot medially inward - Joint movement terms have to do with velocity Posture Terms - relative terms a 0 reference point has to be determined - Flexed – you can be doing extension but still be flexed - Extended – you can be doing flexion and still be extended - Adducted - Abducted - Plantar Flexed – Standard Reference Terminology Anatomical Reference Axes - an imaginary axis of rotation that passes through a joint to which it is attached o mediolateral – axis that goes side to side ex) elbow joint  rotation around this is flexion/extension  movement occurs in the sagittal plane o anterioposterior – axis going from front to back  wrist doing ulnar and radial deviation o Longitudinal Axis – axis going from anterior to inferior  Movement occurs in the transverse plane - There is an axis that is 90 degrees to the plan of motion ex) sagittal motion are mediolateral axis - Know what plane motion occurs in, and that motion is rotation in an axis that is 90 degrees to the plane of motion Mechanical Foundation - Forms of Motion o Translation – movement form one place to another where all point move through the same distance  Every piece in the object you are looking at, moves the same direction in the same increments  Linear – everything moving in a straight line  Curvilinear – still translation because all atoms in object moves the same distance the same amount in the same direction just not in a straight line, more of a curved line o Rotation – rotating around an axis, everything in the object goes through the same angle

in human motion rotation is a huge aspect, all of our body segments rotate around joints and axis o General Motion – combination of translation and rotation  Football moving through space (translation) but spiraling (rotation) at the same time  Human motion is general motion ex) walking the trunk is translation, but the body segments are rotating around an axis but still moving in space  Best description of human movement 

Description of Motion - description of motion is kinematics - Position – a spatial reference system used to standardize the measurements taken o Use a typical Cartesian coordinate system o XYZ system origin at (0,0,0) o Movements in a single plane can be analyzed using the 2D XY system  X – Horizontal  Y- Vertical o Origin – (0,0,0)  For humans it is at the floor so everything is positive o We can take XY coordinates of some location on the system at different points of time  We introduce the 3rd dimension of time o You can have 3 graphs that describe the same motion  X(m), Y(m) – would look like a parabola  Pictures the flight path  Gives the height  X(t), X(m) – would linearly get bigger, only tells us what happens in the horizontal direction  Allows us to calculate horizontal velocity  X(t), Y(m) – looks the same as the first  Gives us the height  Allows us to get the vertical velocity  Time gives us a rate of change over time which is velocity Lecture 3 Mechanical Systems - before determining the nature of a movement the mechanical system of a interest must be defined - in order to look at what kind of motion you have you have to look at the type of body - 3 commonly used systems in the course o something mechanical that is one piece ex) ball  use this when we analyze the out put of in this case throwing the ball  usually looking at something that is started by a human and looking at how effective it was o next one is the whole body  ultimately we have a lot of internal forces that connect series of segments together so we get motion, but it is the whole body that is going to move  you can’t actually find out what is happening at a joint ex) muscle activity, bone and bone force until you separate the body into a series of segments o the last one is the body as segments  series of body segments that are connected at joints

Rigid Link Modeling of the Human - for gross motor movement description and analysis, the human body is modeled as a hinged, linked series of rigid bodies - we assume that each body segment is a series of rigid links, that are connected by hinges o the hinge can move in a couple directions ex) abduction, adduction , internal/external rotation , flexion/extension o symmetric – both limbs mirror images  both limbs ex) both arms are doing the movement together at the same time o non symmetric – limbs are independent  ex) looking at the left and right arm separately - model – to represent mathematically as a basis for measurement o many of these models have assumptions - 6 Segment Symmetric o forearms and hands are a single link o trunk and head area single link o we assume the left and the right as the same o combining several segments together ex) head and trunk  not necessarily valid assumption they are depending on the activity - 12 segment non-symmetric o forearms and hands are a single link o head is now its own compared to the trunk Link Segment Model in Cartesian Coordinate System - create a model with a whole bunch of segments into a Cartesian plane - we identify where each of the joints are, the X, Y coordinates ex) hips, shoulder, elbow - we need a end of every segment even if we put hand and forearm together as a segment ex) forearm and hand combined go from the elbow to the wrist - where the specific joints are in each specific moment of time - this is what motion capture really comes down to, probably one of the most commonly used Biomechanists tool Kinematic Analysis of Human Movement - requires knowledge of the specific biomechanical purpose of the movement and the ability to detect the causes of errors through movement patterns o gives us the amount of body segments we need to look at and which ones - can be qualitative or quantitative - does not include the ultimate cause of the movement (force) o kinetics is where we look at force Performing a Kinematic Analysis - 1. Identify question or problem - 2. Make Decisions o viewing angle, viewing distance, environmental modifications, use of video o Viewing Angle  Name of view  Plane observed  Major joint angles observed  Ex) for adduction/abduction you would want a frontal view o Viewing Distance

Trade offs – resolution, size of field of view The further away you are the more of the person you can observe The close the less of the person you can observe You have to be far enough back in order to view the whole body you are interested over the range that you want to follow for  If you are to far away it become more difficult to define where the joints are as you lose resolution 3. Collect observations, quantitative and/or qualitative o visual, auditory, from performer, from other analysis 4. Interpret observations 5. Communicate with the performer 6. Either end the analysis or refine the question and repeat steps 1-5 kinematic analysis is useful when performance outcome is as a result of changed movement pattern o analysis can differentiate the cause of problem from symptoms of the problem or an unrelated movement idiosyncrasy    

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Tools for Measuring Kinematic Quantitates - Cinematography + Videography o Standard Video – 30 frames/s  Higher rates than this are available o Clarity of images o Number of cameras to capture the information o Computer linked equipment – digitizing o You are restricted in terms of what the frame rate is in terms of what you want to analyze - Other Motion Capturing Systems o Started in Biomechanists o Real time tracking of LED’s o Computer linked cameras track targets o Other Assessment Tools  Goniometer/electrogoniometer  Electro ones allow you to continually measure  Photocells, light beams, and timers  Accelerometer Summary - teachers of PE, clinicians and coaches all perform analyses to correct and improve human movements by reviewing the kinematics of the movement - both knowledge of the specific biomechanical purpose of the movement and careful preplanning are necessary for an effective kinematic analysis Lecture 4 Kinetic Framework Scalars - Scalars – magnitude o Scalar quantities  Mass, volume, length, and speed o No direction just magnitude o The one we will be using the most is mass

 We have the same mass here as we do on the moon o Length is scalar displacement is vector because it has direction Vector - Vectors – magnitude and direction o Kinetic vector quantities  Force, weight, pressure, and torque  Torque – rotational effect of force o Kinematic vector quantities  Displacement, velocity, and acceleration o Vectors are usually illustrated by an arrow as both magnitude and direction are important Adding Vectors - resultant vector - tip to tail vector composition - when adding scalars ex) 15kg and 30 kg you get 45 kg pretty straight forward - when adding vectors you have to take direction into account so it is not necessarily just addition such as in scalar quantities - if the vectors are not in the same direction the resultant vector therefore must be less than the some of the vectors Resolving Vectors - splitting vectors into 2 vectors that are perpendicular to each other - split into 2 components because often we are treating in the vertical and horizontal Graphic Solution of Vector Problems - can be solved graphically using a scale ex) 1 cm = 10 N - if you scaled arrows and added them in the directions that they are acting you can actually use a ruler to measure the distance between the tail of the first one and the tip of the last one to get some sense of what your out come should be Trigonometric Solution of Vector Problems - allows us to derive a more accurate number - when we have two lines perpendicular to reach other lined up tip to tail the resultant C can be solved using the formula A^2 +B^2 = C^2 (Pythagorean theorem) - we need to find magnitude and direction therefore we need to find theta, ex) theta = tan-1A/B (opp/adj) - when resolving we have the magnitude and the direction of C but we don’t have A and B o we use sin cos and the theta to derive A and B Inertia - tendency for a body to resist a change in its state of motion - F = ma o Resistance to motion (a mass) o The bigger the mass the lower the acceleration will be for the same force Mass -

the quantity of matter contained in any object scalar quantity only has a magnitude Symbol – m Units – kilograms (kg)

Force - a push or pull that acts on an object - force is a vector because it has magnitude and direction - also characterized by a point of application o for purposes of human motion assuming that the point of application is center of gravity does not work very well o in linear movement it is fine o but human motion is general motion, linear and angular o angular motion really depends on where you apply the force - something that causes or attempts to cause a change in motion of a body - Symbol – F - Units – Newtons (N) Common Forces in Human Movement - Internal Forces o Muscle force o Joint force  Ligament forces  Bone on bone forces  Between the 2 bones involved in the joint - External Forces o Gravity (weight) o Ground reaction force  Ex) The ground pushing back on you  Essentially where we are in contact with the ground o Friction  Component of the ground reaction of force  The ground is not only pushing up on you there is friction between you and ground allowing you to move forward Key Concept - all forces come in pairs o Newtons 3rd law - the force exerted by one object on another is matched by an equal and oppositely directed force by the second object on the first o ex) pushing on the floor with x amount of force, the floor will be pushing in the opposite direction with equal magnitude o this happens with every force Net Force - resultant force from the addition of 2 or more forces - Units – Newtons (N) - Symbol – (sum of sign) F Adding and Resolving Forces - use vector math Weight - Weight – the force due to gravity, the amount of gravitation attraction to the earth

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Magnitude - Fg=mag Ag – acceleration due to gravity, 9.81 m/s2 on earth o This is where we get Newtons from, Newtons are kilograms x m/s^2 o Direction of this quantity is downwards o Force due to gravity depends on where you are Point of Application – center of gravity o One force that is applied to the center of gravity to whatever the body is o Sometimes we look at the whole body, so whole body weight o Sometimes we look at just the bod segment therefore the center of gravity of that segment Units – Newtons (N) Symbol – Fg

Center of Gravity - Center of Gravity – the point at which the body’s weight is equally balanced no matter how the body is orientated - Concept – where all the weight of the body is considered to be concentrated at a single point and acts down wards from that point Torque - Torque – the rotary effect of a force o What causes or attempts to cause a change in the rotational motion of an object o Sum of moments is the same as the sum of torques - Magnitude – T = F d = Force x moment arm - Direction – CW or CCW around the axis of interest (at joint use joint movement terms such as flexion and extension) - Symbol – T - Units – Newton meters (N.m) Moment Arm - Moment Arm – perpendicular distance from the line of action of the force to the location of the axis of interests (typically at center of gravity of system or at a joint) - Symbol – d (followed by perpendicular sign) - Units – meters (m) Free Body Diagram - Free Body Diagram – sketch that demonstrates a defined system in isolation with all the force vectors acting on the system o We replace the contacts the object experiences with forces Impulse - Impulse – the integration (adding up) of force over time o As a force is applied it is applied over time, relationship of force over time actually changes the momentum of the object - Magnitude – area under a force vs. time graph o If force is constant then impulse = Ft - Units – Newton Seconds (N.s) Tools of Measuring Kinetic Quantities - Electromyography (EMG) o To study neuromuscular function

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o Estimate of muscle activation o Strong relationship between muscle force and EMG, not perfect however because a couple of things affect it Force Plates o To measure ground reaction force o A plate embedded on the ground so as we walk over it it measures the forces in all 3 directions, side to side, back and forth and up and down o o Usually used in gait research Other Force Gauge Examples o Handgrip dynamometer  Measures how strong your grip is o Fish scale

Lecture 5 Linear Kinematics Change in Location - ex) the distance a skater travelled can be marked by the tracks they leave on the ice, their displacement however is the distance of the straight line that connects the start and finish line - distance is scalar does not give you direction - displacements is vector does give you a direction Speed and Velocity - Speed – distance travelled / change in time o scalar - Velocity (v) – change in position / change in time or displacement / change in time o Velocity is a vector because it involves both magnitude and direction o Units – m/s o Instead of distance we use displacement which in its self is a vector Resultant Velocity - ex) the resultant velocity of a swimmer in a river is the vector sum of the velocities of swimmer and the current

Acceleration - Acceleration – rate of change in linear velocity o Change in velocity / time o V2 – v1 / t o Units – m/s ^2 - Maybe positive, nega...