chapter two Flashcards
system
any structure or organization of related structures whose state of motion is of analytical interest
anthropometry
the discipline that studies measurements of the body and body segments in terms of height, weight, volume, length, breadth, proportion, inertia, and other properties related to shape, mass, and mass distribution
body mass index (BMI)
ratio of body mass to height used to describe stature
ponderal index (PI)
ratio used to describe stature
somatotyping
system of body-type description based on weight and muscularity relative to height
ectomorphic
somatotype described as being linear and relatively thin for height
mesomorphic
somatotype described as being muscular, strong, and possessing weight relatively proportional to height
endomorphic
somatotype described as being rounder and relatively heavy for height
waist-to-hip ratio
ratio of waist circumference to hip circumference often associated with disease risk
crural index
ratio of the length of the tibia to the length of the femur
anatomical position
reference position defined by standing erect with all joints extended, feet parallel, palms facing forward, and fingers together
cardinal plane
plane that passes directly through the midline of the body
sagittal plane
vertical plane dividing the body into left and right halves
frontal plane
vertical plane dividing the body into anterior and posterior halves
transverse plane
horizontal plane diving the body into superior and inferior halves
mediolateral axis
axis that passes horizontally side to side and is perpendicular to the sagittal plane
anteroposterior axis
axis that runs horizontally from front to back and is perpendicular to the frontal plane of motion
superoinferior axis
axis that passes up and down and is perpendicular to the transverse plane
center of mass
the point that represents the average location of a system’s mass
center of gravity
the point at which the force of gravity seems to be concentrated
line of gravity
a vertical line representing gravity that passes through a system’s center of mass
cartesian or rectangular coordinate system
a frame of reference defined by an origin and two or three orthogonal axes, each passing through the origin and defining one spatial dimension
origin (O)
a stationary point in the environment, from which all measurements are made
global reference frame
a fixed frame of reference that allows the location of any point to be specified with respect to a defined origin
local reference frame
a frame of reference attached to and moving with the system of interest
roll
a combination of rotation and translation in which each point on a surface contacts a unique location on the other surface
yaw
rotation of a system around the y-axis
pitch
rotation of a system around the z-axis
degrees of freedom (DOF)
the number of independent ways in which a system can move
free-body diagram
a simplified representation of a system free of the movement environment
flexion
segmental motion in a saggiato plane, around a mediolateral axis, and away from the anatomical position
extension
returns a segment to the anatomical position in a sagittal plane around a mediolateral axis and is described as increasing the angle at the joint
abduction
motion in a frontal plane and around an anteroposterior axis that moves the segment away from the anatomical position
adduction
frontal plane motion that returns the segment to the anatomical position
eversion
frontal plane motion around an anteroposterior axis such that the sole of the foot rotates outward or laterally
inversion
frontal plane motion around an anteroposterior axis such that the sole of the foot rotates inward or medially
deviation
frontal plane motion around an anteroposterior axis at the wrist
pronation
rotation at the radioulnar joint around a superoinferior axis that causes the palm to turn toward the body (medially and posteriorly)
supination
transverse plane motion that returns the radioulnar joint toward the anatomical position (palm moves anteriorly)
closed skill
skill performed under standardized or predictable environment conditions
open skill
skill performed in a changing or unpredictable environment
motion
a change in position with respect to both spatial and temporal frames of reference
force
something that possesses the capability to cause a change in motion or shape of the system
relative motion
the motion of one object with respect to a reference object
translation
motion along one of the x-, y-, or z- axes; linear motion
rotation
motion around a fixed axis and therefore in a circular path; angular motion
spin
occurs if all points on one articulating surface come in contact with one point on another articulating surface
glide
sliding or pure translation in which a point on one surface glides or skids over many points of an opposing surface
roll
rotation of a system around the x-axis
discrete skill
motion that has a definite beginning and end point
continuous skill
cycles of motion performed repeatedly with no well-defined beginning or end points
repeated discrete
cycles of motion that are seemingly continuous but require a recovery phase between propulsive actions
serial skill
movements that comprises a series of discrete motions
gross movement
motion that is the result of large muscle group activity and requires little precision
fine movement
motion that is precise and generally controlled by small muscle groups
kinetic chain
system of linked rigid bodies subject to force application
serial or simple kinetic chain
kinetic chain in which each segment participates in no more than two linkages
complex kinetic chain
kinetic chain in which a segment is linked to more than tow other segments
mobility
the total degrees of freedom of a kinetic chain
open kinetic chain
kinetic chain in which motion can occur at one link in the chain without cooperative motion at other links
closed kinetic chain
kinetic chain in which motion at one link is only possible with cooperative movement at other links
functional kinetic chain
a complex kinetic chain in which some links are involved in open chain motion and others are engaged in closed chain motion
