lecture 11 levers and torque Flashcards
The _____ experienced by an object is determined by adding up all the individual force vectors acting upon that object
net force
The force created by the muscle is called a ____
force vector.
Two vectors can be added together to determine the _____
result (or resultant)
Vertical component (rotary component) of the force vector is _____ to the moving bony lever
perpendicular
______ completes the right angle triangle and either acts to compress or distract the joint
Horizontal component
At joint angles less than 90 degrees the horizontal component of the force is ____
stabilizing (compressive
At joint angles of 90 degrees as in Figure B, the horizontal component of the force is_____
neutral
At joint angles greater than 90 degrees the horizontal component of the force
is ____
destabilizing (distracting)
vectors have ___ and ____
magnitude and direction
Increasing the angle of pull increases the _______ of the muscular force and improves efficiency of the muscle
rotary component
pulleys increase _____
rotary component
Levers are rigid bars (bones in our case) that act around a _____ when a force is applied
fulcrum (joint)
First Class Lever Axis lies between _____and _______
effort (force), resistance
First Class Lever advantage
balance
example of first class lever
occiput on c1
Second Class Lever Resistance lies between the ______ and the _____
effort force, fulcrum (axis
Third Class Lever Effort force lies between ____ and the____
fulcrum, resistance
third class lever example
bicep flexion
Third Class Lever Advantage ______ end despite small ROM at effort end of lever
increased ROM at resistance
Third Class Lever Disadvantage ___
large effort required to overcome resistance
**a joint force of 30 degrees is stabilizing or destabilizing
stabilizing
_____ is the turning or rotary force generated by a muscle
Torque
_____ is the perpendicular distance between the muscle force vector and the axis of rotation
Moment arm
The _____ component generates rotation and is perpendicular to the moving bony lever
vertical (Y-axis)
The _____ vector acts to compress or distract the joint
horizontal
the _____vector is a factor in producing torque
vertical
***Torque is ____ when the muscle force vector is applied at 90 degrees to its bony lever as this is when the moment arm is longest
greatest
In the case of knee extension, the patella increases the _____ for the force of quads as a group
moment arm
