Fall review for quiz 1 Flashcards
in what direction does the roll occur in arthrokinematic movements?
in the direction of osteokinematic movement
in what direction does the slide/glide occur in arthrokinematic movements?
direction of motion, dependent on joint structure
when a concave articular surface moves on a relatively stationary convex surface roll and slide occur in…
same direction
when a convex surface moving on a concave surface roll and slide occur in…
opposite direction
for open chain tasks eyes should look at ________ segment to determine the roll
distal
for closed chain tasks eyes should look at ___________ segment of the joint to determine the roll
proximal
define moment arm
the perpendicular distance from the line of action to the axis of rotation
define rotary arm
the perpendicular distance from the point of application on a lever
define a lever arm
distance from the point of application of the force to the axis of rotation
what is creep?
when load is suddenly applied and then held constant overtime, continued deformation over time though load is held constant
what is stress relaxation?
deformation held constant, force required to maintain a deformation decreases over time
what is a vector component?
goes in the force of muscle fiber orientation, always parallel to the lever from the POA
what is a compression component?
the vector goes into the joint or POA is superior to joint
what is a tension component?
the vector goes away from the joint or POA is inferior to joint
what is a rotary component?
torque always perpendicular at the POA
POA
point of application; location where the force is applied
LOA
line of action; direction and angle of the force
define magnitude
length of vector
what is an open kinematic chain?
distal joint segment is free to move while proximal segment provides stability
what is a closed kinematic chain?
distal joint segment is fixed from moving while proximal segments are allowed to move on stable distal segments
what is a first class lever?
fulcrum is in the middle
what is a second class lever?
fulcrum –> resistance –> effort
what does a second class lever favor?
power and efficiency
what type of contractions are second class levers?
eccentric
what is a third class lever?
fulcrum –> effort –> resistance
what does a third class lever favor?
speed and ROM
what type of contractions are third class levers?
concentric
what is mechanical advantage?
greater the efficiency the less effort necessary to overcome a greater resistance MA= EA/RA
what mechanical advantage do first class levers have?
MA = 1
what mechanical advantage do second class levers have?
MA > 1 (most efficient)
what mechanical advantage do third class levers have?
MA < 1 (least efficient)
what is a moment?
moment = potential torque
why is torque always applied off center?
because there needs to be a max force
what does max force rely on?
timely addition of joint torques
max torque production at each joint
participation of all joints possible
if the sum of torques = 0 …
static equilibrium
what effect does reducing gravity have and how can it be accomplished?
it makes it easier on the patient… we can put them in gravity eliminating position
how can we effect the MA of gravity?
move the center of mass closer to the joint
how can we alter the MA of muscle?
alter angle of joint to optimal mid position of that joint
how can we alter the muscle?
alter the joint angle
what is an active insufficiency?
must cross two joints. agonist muscle has either too much or too little myosin and actin overlap.
what is a passive insufficiency?
must cross two joints. antagonist muscle is stretched but it is too short to allow further movement
if the PT can not take the patient any further than where the pt could take themself is this an active or passive insufficiency?
passive
if the PT can take the patient any further than where the pt could take themself is this an active or passive insufficiency?
active
what are the 3 cardinal planes
sagittal, frontal, and transverse
the sagittal plane is about or around what axis?
medial-lateral
the frontal plane is about or around what axis?
anterior-posterior
the transverse plane is about or around what axis?
longitudinal or vertical
what directions occur in the sagittal plane?
flexion/extension
what directions occur in the frontal plane?
abduction/adduction (lateral flexion)
