biomechanical applications to joint structure + function Flashcards
what type of displacement is this:
- linear/straight line
- rare in human movement
translatory displacement
what type of displacement is this:
- angular
- movement of segment around a fixed axis
rotary displacement
curvilinear motion
2D joint motion
is the screw home mechanism an example of 3D or curvilinear motion?
3D
sagittal plane axis + direction of movement
x-axis (coronal)
flexion/extension
transverse plane axis + direction of movement
y-axis (vertical)
int/ext rotation
frontal plane axis + direction of movement
z-axis (anteroposterior)
ab/adduction
translation unit of measure
inches, feet, meters, etc
displacement per unit of time REGARDLESS of direction
speed
displacement per unit of time IN A GIVEN direction
velocity
measurements for…
linear velocity
angular velocity
acceleration
linear velocity (m/s)
angular velocity (deg/sec)
acceleration (m/sec^2 or deg/sec^2)
units of force (2)
newtons
pounds
force is directly proportional to…
mass and acceleration
what is the most consistent and influential external force
gravity
basic examples of internal forces
muscles
ligaments
bones
tendons
what is force represented by on diagrams
an arrow (vector)
vectors can represent which 2 types of forces
push
pull
COM in adults
S2
BOS in adults
between the feet
dynamic equilibrium
object moving at a constant velocity (zero acceleration)
“balanced forces”
t/f: unbalanced forces result in acceleration
true
newton’s 1st law
law of inertia
an object will continue in current motion until a force causes the speed or direction to change
when the sum of forces/torque are not equal to zero, then the object must be doing what?
accelerating
Newton’s 2nd law
law of acceleration
acceleration is DIRECTLY proportional to unbalanced forces/torques
acceleration is INVERSELY proportional to the mass (m) or moment of inertia (I)