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Tony Leyland (778) 782-4338 [email protected] http://www.sfu.ca/~leyland/
See website for more information
Definition of Biomechanics
The area of study wherein the knowledge and methods of mechanics are applied to the structure and function of the living human system.
Course Outline
Lecture Schedule Text Readings Tutorial Attendance Evaluation
Assignments Exams
My Website + Kin 201 Course Website
http://www.sfu.ca/~leyland/
Not all slides are on the
web.
Course Prerequisites KIN 142 (a must, especially
functional anatomy) PHYS 101 or 120 or 125 or 140
(a big help with most problems) MATH 151 or 154 (essential
for some sections) MATH 152 or 155 (can be taken
concurrently so less essential)
The picture above shows KIN 201 student reviewing prerequisite information!
Strongly Recommended Course Text
Andy Kerr Introductory Biomechanics Churchill Livingstone Elsevier, Edinburgh, 2010.
Read Chapter 1 The text will be on library reserve as are many other biomechanics texts. I do not always follow the text sequentially which is why it is recommended not required.
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Qualitative vs. Quantitative
good fifty revolutions poor three seconds long six meters heavy 25 kilograms flexed 45o angle
Course Text The course text is the foundation of required
information presented in a qualitative format. However, the course requires good
quantitative knowledge which you can learn from the lectures, tutorial and course website (and additional books on reserve if required).
You cannot get all of the information via the text.
This course has a large quantitative component.
Kelvin (1891) “I often say that when you can
measure what you are speaking about and express it in numbers, you know something about it: but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind”.
Oscar Wilde “Education is very admirable but
let us not forget that anything worth knowing cannot be taught”
in other words
you get out what you put in!!
e.g. If you don’t buy the text – or use a reserve text – you have to come to lecture!
Common Misconceptions
If I don't lecture on the material it isn’t covered.
If I do lecture on the material it is covered!
Problem Based Learning
I believe that you don’t learn unless you do! How would you learn to perform a jump
shot in basketball? The same is true of biomechanical
concepts. You have to practice using them to fully learn them.
http://www.sfu.ca/~leyland/Kin201%20Files/PBL.pdf
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Downloads Required Soon
http://www.sfu.ca/~leyland/Kin201%20Files/Outline.pdf ………./PBL.pdf ………../Freebody.pdf ………./Equations.pdf ………./Anthropometry.pdf
These are located at the top of the Kin201 webpage.
Who Needs Biomechanics?
Ergonomists (postural strain, back injuries, repetitive
strain injuries, etc.)
Newtons “Rehabilitators”
(mechanical function of musculoskeletal system)
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Musculoskeletal Injury Many different disciplines have a role to play
in a comprehensive understanding of injury. However, of all the scientific disciplines,
physics and its sub-discipline mechanics are arguably most central to the study of injury.
The fundamental relation between mechanical energy and injury highlights biomechanics as the logical discipline to study the causes and effects of human musculoskeletal injury.
Whiting & Zernicke, 1998
Foot Pressure
Internal Forces Coaches & Physical Educators (optimal sports performance
and/or injury prevention)
Maximal foot / racquet velocity at contact?
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21 mvrgyKineticEne =
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Mechanics of Exercise Variable Resistance (leverage {force x distance})
Biomedical Engineers
Definitions
Kinematics study of motion (space/time)
Kinetics study of forces causing or resulting
from motion
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Kinematics
Squats
Ground reaction force while performing squats
Kinetics
Muscle moments (torques) while performing squats
Human Movement Analysis
DisplacementVelocity
Acceleration
Linear
DisplacementVelocity
Acceleration
Angular
Kinematics
Force
Linear
Torque(Moment of Force)
Angular
Kinetics
Biomechanics
Functional Anatomy
Kinesiology
Definitions
Statics constant motion
Dynamics acceleration present
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Anatomical Terms
Chapter 1
Movement Terminology Movement Description
See text or web
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Functional Anatomy http://www.exrx.net/
Axis of Rotation pivot point for an angular motion
Direction Perpendicular to
sagittal axis (anteroposterior
axis)
horizontally from the front to
the back frontal plane
transverse axis (frontal axis or horizontal axis)
horizontally from side to side sagittal plane
vertical axis perpendicular to the ground transverse plane
Back to them prerequisites!
Movement Analysis List joint movement
and the main agonists for each action.
State whether the muscle is working concentrically or eccentrically. Muscle moments (torques)
while performing squats
Text Activity 1.1
Muscle Contraction Concentric Eccentric Isometric
You want more?!
Again for a down and up phase. List joint movements and the main agonists
for each action. State whether the muscle is working
concentrically or eccentrically. List major stabilizers.
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http://www.exrx.net/ Systems and
Free Body Diagrams
http://www.sfu.ca/~leyland/Kin201/Freebody.pdf
Systems
“A system is a body or group of bodies or objects whose motion is to be examined”
Ground reaction force
Body weight (minus weight of foot)
Muscle forces
mg
System Once you have correctly
identified the system you can analyze what forces can cause the system to move.
Although muscular force is required to move, it is not the actual force that propelled this goalkeeper into the air.
What force did?
Internal & External Forces
System = windsurfer board and sail.
Internal forces Muscle forces, force of hands on boom, ?? External Forces Force of water on board, air resistance, gravity, ??
Reaction Forces
Although internally initiated movements of the segments are required to move the body (due to force of muscular contraction), to move a system an external force must be present.
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“in other words....”
You have to push or pull against something to make your centre of gravity, or the CG of an object, move.
You can’t pull yourself up by your boot laces!
Free Body Diagrams
Read the web pages on free body diagrams.
This is a crucial skill in the analysis of human movement.
Draw all forces acting on runner What would the diagram look like if you drew a free body diagram of the foot and shank?
It is best not to draw stick figures for general FBDs
Cause and Effect The cause of movement of a body or
segment is due to: muscular force (torque) gravitational force, or another external force like an opponent
in a wrestling match I often get students say things like “the
arm bends increasing the torque”. Your muscles are your force generators.