chapter three Flashcards
composite approach
qualitative analysis approach that views the whole body as a system that progresses through stages or phases as it refines movement patterns
component approach
qualitative analysis approach that views the body in component sections, with each section progressing through more refined steps toward mature movement patterns
scalar quantity
a quantity that can be fully specified simply with a single numerical magnitude of appropriate units
mass (m)
the quantity of matter of which a body is composed
inertia
a body’s resistance to having its state of motion changed by application of a force
vector quantity
a quantity that can only be fully specified with a magnitude of appropriate units and a precise direction
weight
measure of the force with which gravity pulls on an object’s mass
direction
sense or way in which a force is applied; represented by the tip of a vector
orientation
the alignment or inclination of the vector in relation to the cardinal directions
point of application
the point or location at which a system receives an applied force; usually defined by the tail of the vector
magnitude
size or amount of an applied force; represented by the length of a vector
line of action
an imaginary line extending infinitely along a vector through both the tip and tail, representing the path along which the vector would travel if moved forward or backward
polar coordinate system
a coordinate system in which the location of the given point is defined by its distance (radius) r from the origin and by the angle between the chosen reference axis and the line formed by connecting the given point to the origin
plane polar coordinates
coordinates representing the location of a point within a polar coordinate system
pythagorean theorem
an expression of the relationships (ratios) between the lengths of the sides of a right triangle: r = square root of x^2 + y^2
vector equality
property that two vectors are considered equal (A=B) as long as they possess the same magnitude and orientation
commutative law of addition
the sum of vectors added together 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)
negative of a vector
another vector that, when added to the first, gives a sum equal to zero
resultant
a single vector representative of the sum of multiple vectors
vector resolution
the process by which individual directional component vectors of a single vector are determined
component vectors
the individual vectors that are representative of each of the multiple effects that one vector represents
vector chain
a form of vector analysis in which vectors are arranged tip to tail
vector composition
process by which two or more vectors are summed to determine a single resultant vector
colinear vectors
vectors that have the same line of action
rotary component
the vertical or perpendicular component of a muscle force vector representing the amount of force that would tend to cause joint rotation
stabilizing component
the horizontal (parallel) component of a muscle force vector directed toward the joint, representing the amount of force that would tend to stabilize the joint
destabilizing component
the horizontal (parallel) component of a muscle force vector directed away from the joint, representing the amount of force that would tend to destabilize the joint
Q angle
the quadriceps angle formed by the longitudinal axes of the femur and tibia, which approximates the resultant line of action of the quadriceps muscles
line of pull
resultant line of action of a muscle force vector
teaching cues
single words or short phrases that identify critical elements of a skill
