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70 Cards in this Set
- Front
- Back
What is video analysis used for?
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Time resolution? Clarity resolution? |
Time - Frame rate (how quickly a camera can capture subsequent images) Clarity - Pixel count |
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Motion blur?
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indication frame rate is not fast enough to capture movement |
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pixel resolution?
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how many pixels camera can develop High pixel count= very detailed images |
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What time of zoom will disturb pixel resolution?
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Digital zoom cause it focuses on specific pixels unlike optical zoom which uses lens to amplify the image
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What is the purpose of physical markers when making videos?
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For visual reference of anatomical landmarks, markers can often be automatically tracked by video software |
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4 phases of qualitative analysis?
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Preparation observation evaluation/diagnosis intervention |
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What are the 3 steps of preparation? |
2.) knowledge of skill specific considerations - goal of movement, knowledge of performers(level of athlete), observational bias, knowledge of effective and appropriate instruction 3) develop systematic strategy for observation |
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4 important observational considerations? |
1. FOR
2. FBD 3. Vectors - how to visualize forces and movement 4. QAA - basic functional anatomy |
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Frame of reference?
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way to describe an objects position in space and whole body orientation alone and with respect to external landmarks |
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What is the purpose of having parallel axis?
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- used to determine postural abnormalities in the frontal plane |
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From a frontal plane what postural abnormalities can be viewed using a parallel axis?
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if one hip or shoulder girdle is higher then the other |
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using a parallel axis what abnormalities can be viewed from a saggital plane?
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lordosis |
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using the idea of FOR what will you be able to detect?
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how to view movement Individual movements of body segments - balance/imbalance |
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Benefits of FBD? |
- Removes all unnecessary visual info
- Focus simply on structural movement - Rigid segments where forces act |
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Limitations of FBD?
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Depth - Is each limb well represented by a 2D stick figure? ROM Subjectivity - did we get accurate joint centers, did we misrepresent usefull info |
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Important properties of Vectors? |
Magnitude - length of vector point of application |
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Magnitude? Direction? Line of action? Point of application? |
- length of arrow - relative to an axis - shaft of an arrow - where it acts (another object) |
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Example? |
when you jump and land there is a force from the lower leg onto the upper leg and vice versa |
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Internal pulling forces?
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- similar to tension in rope when pulled |
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internal pushing forces?
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Compressive forces object being compacted when tensile or compressive factors on a structure are greater than the structure can withstand, structure will fail..aka broken bones, pulled muscles... |
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External Forces?
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Gravity, magnetic, electrical |
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What does gravitational attraction depend on? |
Amount of mass each object has and distance btw 2 objects |
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Contact forces and example
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- solid or fluid |
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Static friction?
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Occurs when 2 objects in contact are not moving relative to one another |
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Dynamic friction?
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Occurs when 2 objects in contact begin to slide relative to one another |
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force summation? |
Internal forces in body (muscular actions transferred through tendons and ligaments) can add together to act upon an external object to move either the object or ur body |
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Force-motion principle?
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- without external forces, body cannot change its general motion |
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3 degrees of freedom for glenohumereal joint?
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abduction/adduction medial/lateral rotation |
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3 directions of scapula? |
2. protraction/retraction 3. upwarwd/downward rotation |
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movement of the hip?
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ab/add med/lat rotation |
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QAA (qualitative anatomical analysis) ?
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analysis technique to determine which muscles are necessary to produce movements, when they are active and what type of contraction they produce |
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steps of a QAA?
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2. identify joints involved and movements at joints 3. types of contractions and active muscles groups 4. instances of rapid joint accelerations and impact 5. identify any extremes in joint ROM's |
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What is motion? |
change in position requires space (spatial) and time (temporal) |
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Rotary motion? |
Circular motion about an axis
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Rotary motion? |
Circular motion about an axis
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General motion? |
Combo of linear and angular |
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Kinematics? |
Study of motion exclusive of influences of mass and force, based on displacement and velocity and acceleration |
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Distance? |
Measure of total path taken - scalar quantity - how much ground the object covered on its path |
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Displacement? |
Measurement of shortest distance from beginning to end of path -vector quantity, how far out of place an object is from its original position |
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Scalar quantity? |
Quantities fully described by magnitude alone
Eg. 10 paces (no direction) |
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Vector quantity? |
Quantity described by both magnitude and direction (always the shortest distance)
Eg. 10 paces east |
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3 important requirements to be able to use video to measure kinematics? |
1. Camera did not move 2. Movement of object occurred in plane of camera 3. Reference measurement to convert pixels to meters |
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Speed is? |
How fast object is moving -scalar quantity -distance/time |
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Velocity?
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- displacement/time - vector quantity (need to identify a direction. eg. east, west) |
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average speed is?
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> (final distance - initial distance)/(final time - initial time) |
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Average velocity?
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- final - initial |
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Acceleration?
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Rate at which object changes its velocity - Vector quantity - proportional to velocity, inversely proportional to time accel = change in velocity/change in time |
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Kinetics?
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Mass, force and energy
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Kinematics?
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Displacement, velocity and acceleration
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What is inertia?
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Resistance to change in state of motion
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What is force?
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A push or pull acting on a body that causes or tends to cause a change in motion of the body - vector |
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newtons first law?
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object at rest stays at rest, object in uniform motion stays in uniform motion unless acted on by net external force
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According to newton what is mass?
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tendency for an object to resist change in motion - a measure of inertia - greater the mass, greater the inertia therefore, force must overcome mass to get something moving or to stop it from moving |
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Static equilibrium?
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Sum of forces acting on person in all directions is zero and person will maintain their state of motion
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Most important rule for conservation of momentum?
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Sum of momentum before collision must equal sum of momentum after collision
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Momentum? |
Tendency for object to resist change in motion, during motion, and continue traveling along its path
P(momentum)= m(inertia)v(in motion) Vector |
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Elastic collision?
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when 2 objects collide and bounce off one another - eg. pool table balls |
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In an elastic collision with objects of different mass, how is mass transferred? |
From object of more mass to object of lesser mass |
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Inelastic collision? |
When 2 objects collide and stick together and behave has one object after collision M1v1+m2v2=(m1+m2)v |
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Coefficient of restitution? |
Bounciness
Absolute value of the ratio of the velocity of separation to velocity of approach |
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Velocity of separation?
Velocity of approach? |
VOA- how fast object is moving before it hits the ground
VOS- how fast an object is moving after it hits the ground |
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How can we determine COR?(coefficient of restitution) |
By observing the drop height relative to the bounce/rebound height |
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Newton's second law? |
Law of acceleration
If force exerted on object, object will accelerate in direction of net force and acceleration will be proportional to force
- F=m/a |
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If I am holding a tennis ball in my hand how much force must I exert to lift it upwards? |
Force exerted upwards must be greater then the weight of the tennis ball - once velocity is changed we only need to match gravity to keep object moving |
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How do we slow down the tennis ball in my hand? |
Reduce force to a mass less then the force of gravity from the ball |
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Impulse? |
Measure of the amount of time a force is applied
Impulse=Ft |
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How can we change an objects velocity using impulse? |
Produce larger force over short time or less force over short time |
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What limitations are there to increasing and decreasing momentum? |
Limited by force we can apply(muscles etc r only so strong)
Limited by time we can apply it(we are only so fast) |
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Newtons 3rd law? |
Every action has an opposite and equal reaction
When object 1 exerts force on object 2, object 2 exerts same force back to object 1 |