PowerPoint 3 Flashcards
What are the two general approaches to qualitative analysis?
Composite approach
Component approach
What is the composite approach?
Also known as the total body approach, views the whole body as a system that progresses through phases as it refines movement patterns
Total body approach often referred to as “developmental biomechanics”
Breaks down movement patterns into primary body parts
However, the stages of skill progression are based on the product of all body parts in combination.
Each stage identifies important body parts used to perform the skill, and the number of stages can vary depending on the requirements necessary to perform a task.
What is the component approach?
Uses the same phase/stage method (defined as steps), but rather than looking at the body as a global system, it breaks the body down into component sections
Sometimes called “error analysis strategy”
Each primary body component is observed.
Ex: Foot Action, Trunk Action, Backswing, Humerus action, Forearm.
Each component has its own evaluative series of stages or phases that can be advanced independently of each other.
Performers could show evidence of mature skill performance in one part of the body, while other body segments are at less mature levels.
Where does quantitative motion analysis stem from? (examples)
Stems from the simple need for a deeper and more specific understanding of why the system moves the way that it does
(Enhance performance of elite athletes
Physical therapists and athletic trainers have a need to quantify severity of injury and/or treatment success.
Biomechanical research—goal of understanding human motion, optimizing sport performance, improving equipment design, and/or preventing injury)
Scalar quantity?
A quantity that possesses only a magnitude but has no particular associated direction
Mass?
Quantity of matter of which a body is composed; a measure of a body’s inertia
Inertia?
A body’s resistance to having a state of motion changed by the application of a force
Vector quantity?
Can only be fully specified with a magnitude of appropriate units and a precise direction
Weight?
A measure of the force with which gravity pulls upon an object’s mass
What are arrows used for in free-body diagrams?
Arrows are used to represent forces in free-body diagrams.
Arrows are appropriate because all forces are vectors.
What principles should be kept in mind when drawing vectors?
A tip and tail, a length drawn to scale, and an imaginary path along which it would travel
What are the five areas of graphical representation of force and the definitions of these areas?
-Direction: the way in which the force is applied
-Orientation: alignment or inclination of the vector in relation to cardinal directions
-Point of application: the point or location at which the system receives the applied force
-Magnitude: amount or size of the applied force
-Line of action: imaginary line extending infinitely along the vector through the tip and tail
What does biomechanics require a description of?
Single points, segments, and forces
____ ____ ____ allows for specific definition of an objects position in space by establishing one or more frames of reference?
Cartesian coordinate system
It is sometimes more convenient and necessary to define a ____ ____ ____ and locate a point in space using its ____ ____ ____?
Polar coordinate system… plane polar coordinates
SOHCAHTOA
Sin=opposite/hypotenuse
Cos=adjacent/hypotenuse
Tan=opposite/adjacent
Pythagorean theorem?
R^2 = X^2 + Y^2
What is trigonometry based on?
Simple ratios of the lengths of two sides in a given triangle
What is vector equality?
Two vectors are considered equal if they possess the same magnitude and direction (A = B)
Commutative law of addition?
When vectors are added together, the sum is independent of the order of addition (A + B = B + A)
Associative law of addition?
The sum of three or more vectors is independent of the grouping of the vectors for addition. (A + B) + C = A + (B + C)
What is vector subtraction?
Negative of a vector: a vector that when added to the first gives a sum equal to zero (the vectors that have the same magnitude but point in opposite directions). A + (-A) = OA – B = A + (-B)
What is vector multiplication?
When multiplying (or dividing) a scalar by a vector, the product is a vector quantity, e.g., scalar number = -9, vector = A. The product of scalar x vector = -9A
Multiplying one vector by another results in another vector: A x B x C
How can graphical vector analysis be used?
Can be used to understand:
the multiple effects of one force
the resultant motion of the system that is acted upon by many different forces simultaneously
What is vector resolution?
Process by which individual directional component vectors of a single vector are determined
What are component vectors?
The individual vectors that represent each of the multiple effects that one vector represents
What is a vector resolved into?
Horizontal component (parallel to the x-axis)
Vertical component (perpendicular to the x-axis)
What is vector composition?
Two or more vectors are summed to determine a single resultant vector, i.e., a situation where multiple forces act upon a system, and we would like to find the resultant force vector
What is a resultant vector?
-A vector that represents the sum of all forces acting upon a system
-Resultant motion of a system that we observe is composed of many individual forces
-Forces may be applied simultaneously or sequentially.
What are two factors that affect the complexity of vector composition?
Number of vectors
Relative directions and orientations of the vectors
