Biomechanics Flashcards
_________ = the use of mathematical and physical principles to study and understand movement.
biomechanics
_______ = the study of movement without regard to the forces that cause the movement
kinematics
_____ = the study of the forces causing movements
kinetics
What are the 3 cardinal planes of motion?
- frontal
- sagittal
- transverse
What are the 3 axes of motion?
- anteroposterior
- mediolateral
- longitudinal
Movements occur ___ a plane of motion, _____ an axis of rotation.
in; about
In the frontal plane of motion, the axis of rotation is ?
anteroposterior
In the sagittal plane of motion, the axis of rotation is?
mediolateral
In the transverse plane of motion, the axis of rotation is ?
longitudinal
What is Newtons first law of linear motion?
Every object in a state of uniform motion tends to remain in that state of motion unless and unbalanced, external force is applied to it.
What is Newton’s second law of linear motion?
An object of mass will accelerate promotional to the force applied to it, and inversely to its mass
What is Newton’s this law of linear motion?
For every action force there is a reaction force equal in magnitude and opposite in direction
________ = movement between joint surfaces
arthrokinematics
________ = movement between bones
osteokinematics
Osteokinematics is used to describe movement characteristics in terms of _______ and _______.
magnitude; timing
_______ ______ = a linkage of rigid bodies
kinematic chain
In an _____ chain, one end of the chain is free to move
open
In a _____ chain, there is a constraint imposed on both ends of the chain.
closed
What two things can acceleration be?
- The calculated/measured acceleration caused by a force
2. A constant, such as gravity
How much an object deforms relative to how much force is applied to it = ?
stress strain curve
The _____ of _____ is like the stress strain curve, but what we experience in a typical day.
envelope of function
The envelope of function is a relationship between what two variables?
- load
2. frequency
Overstepping your maximum capacity to adapt will result in what 3 things?
- Pain during effort
- Pain after
- Morning stiffness
What are the 3 types of internal forces?
- isometric
- concentric
- eccentric
_________ force occurs when force is generated by the muscle but is equivalent to external resistance.
isometric
The relationship between what two variables will dictate the resultant linear/angular motion of a segment?
- internal forces/moments
2. external forces/moments
_________ are the angular equivalent of force.
moments
A moment is a _______ of the amount of force applied and the ________ from the force to the point of rotation
function; distance
The moment arm is the _______ distance from the line of action of the _____ application to the axis of rotation.
perpendicular; force
Linear forces and angular rotations occur _________.
simultaneously
________ _________ = kinematic movements occurring about cardinal planes of movement
angular rotations
_____ force = perpendicular to segment
shear
____ force = parallel to segment
compression
How does Newtons second law of motion change when taking about angular motion?
An object of inertia will angularly accelerate proportional to the force applied to it and inversely to its mass
Biomechanically, the magnitude of the moment is mainly dependent upon the ____ _____.
joint angle
A lever is a rigid body that, when subjected to a force, exerts force on any object impeding its tendency to ______.
rotate
What is a first class lever?
Muscle force and resistance force act on opposite sides of the axis
What is a second class lever?
Muscle force and resistance force act on the same side of the axis of rotation
What is a third class lever?
Muscle force and resistance force act on the same side of the axis of rotation
What class of lever are most anatomical levers?
3rd
Mechanical ______ = the ratio of the muscle moment arm to the resistance moment arm.
advantage
What is the formula for mechanical advantage?
MA = moment arm (muscle)/ moment arm (resistance)
Increased MA ________ the need for increased muscle force.
reduces
Stress and load are interchangeable terms (T/F).
TRUE
_______ are the angular equivalent of force.
moments
_______ is the amount of turning force about a particular joint of interest
moments
Because muscles have origins and insertions away from the axis of rotation of the joints in which they cross, the _____ forces that hey exert along their line of action is translated into _____ forces (moments)
linear; angular
If the moment arm is 0, then no moment is created regardless of the magnitude of the force( T/F)
TRUE
What are 4 types of linear forces?
- Compression
- Distraction/tension
- Shear
- Torsion
Forces _____ occur perpendicular to an object/segment/body
rarely
Angle of ____ of force will dictate relative forces
application
Since forces rarely occur perpendicular to an object/segment/body, different forces often occur _________
simultaneously
In the human body, it isn’t ___ to have adjacent segments separated.
ideal
There is always an ____ of _____, and muscle force will always result in rotation of one segment with respect to the other.
axis of rotation
We can think of linear muscle forces being transferred into angular forces acting on a segment, which is called _____ _____.
joint rotation
Muscles generate force along their ______ _____.
muscle bodies
Angle of _____ will dictate relative compression/tension/shear
insertion
Moments cause _____ _____ due to linear force production when one end of the linkage is fixed.
angular rotation
Linear forces and angular rotations occur ________.
simultaneously
In a compression force, the moment arm = ?
0
In a perpendicular force, moment arm = ?
> 0
You cannot get rotation without some ___________ between adjacent segments.
shearing
In moment assessment, your job is to test maximal ________ muscle strength.
isometric
What are the two major competing factors in moment profiles?
- muscle moment arm lengths
2. muscle length-tension relationship
Optimal length will be _____ specific.
muscle
Human movement is the result of translating ______ muscle forces into ______ segmental forces.
linear; angular
What dictates the direction of rotation?
net moment
What is the key factor in moment magnitude?
joint angle
Effect of joint angle is _____ and _____ specific
joint; direction
In human movement, there is alway an _____ of _____, and muscle forces will always result in rotation of one segment with respect to the other.
axis of rotation
What is the formula for a moment?
force magnitude x moment arm
Does knee OA affect just part or all of the joint?
all
Where does the GRF travel when you step down ?
From the foot to the COM
Does the GRF pass through the knee joint?
NO
What movement does the GRF tend to cause?
adduction of tibia
A higher knee adduction moment leads to higher compression force where?
Medial compartment of the tibia
High knee adduction moment does not translate to high forces inside the knee joint (T/F).
FALSE
Is the knee adduction moment higher or lower in patients with OA?
HIGHER
Knee adduction moment is related to disease _______ and ______.
severity; symptoms
The knee adduction moment predicts tibial ______ ______ _______.
bone mineral density
What are the 7 factors in knee adduction moment validity ?
- Correlates with implantable load measurements
- Higher in OA vs. no-OA
- Related to disease severity
- Related to symptoms
- Predicts tibial BMD
- Predicts disease progression
- Predicts treatment success
What is occurring in order to oppose the GRF and abduct the tibia?
collision of tibia and medial condyle of femur
In a typical individual, how much load is transferred through the medial compartment of the tibia and femur?
85%
What are 2 external contributions to movement?
- Gravity (limb weight)
2. External forces (GRF)
What are 4 internal contributions to movement?
- Muscle forces
- Ligaments
- Bone
- Other soft tissue
Does toeing out increase or decrease the GRF?
Decreases!
Leaning trunk towards the stance leg increases or decreases knee adduction moment?
Decreases!
