Quiz 1 Flashcards
what is kinesiology?
the study of human movement and how movement affects tissues
why is kinesiology important to PTs?
injury prevention, optimal performance, and recovery of function
what is biomechanics?
application of physics principles to quantify how forces interact within a body
what is kinematics?
motion without regards to forces or torques
what are the 2 types of kinematics?
osteokinematics and arthrokinematics
what is kinetics?
forces that resist or produce movement
what are the 2 types of kinetic forces?
internal and external
what is osteokinematics?
movement of boney levers through their ROM
motion of bone segments in one plane around a corresponding axis
what is the sagittal plane?
the plane that divides the body into left and right
parallel to the sagittal skull suture
what is the frontal plane?
the plane that divides the body into front and back
parallel to the coronal skull suture
what is the transverse/horizontal plane?
the plane that divides the body into upper and lower halves
what axis goes through the frontal plane?
the z/anterior-posterior axis
what axis goes through the sagittal plane?
the x/medial lateral axis
what axis goes through the transverse plane?
the y/vertical axis
what is translatory/linear motion?
motion parallel to the axis
can be a straight or curved line
what is an example of linear motion in the human body?
the carpal bones sliding next to each other
the head moving in a curvy linear path as you walk
what is rotary/angular motion?
motion around an axis in a circular pattern
what is an example of rotary/angular motion in the human body?
the forearm moving along the arc of a circle where the joint is he axis of rotation
what are the 4 types of endfeels?
soft, hard, firm, empty
what are degrees of freedom?
the number of axes about which a joint can move
what does one degree of freedom mean
the joint is uniaxial and the segment only moves in 1 plane around 1 axis
what joints are uniaxial with 1 DF?
hinge and pivot joints
what does 2 degrees of freedom mean?
the joint is biaxial and the segment moves in 2 planes around 2 axes
what joints are biaxial with 2 DF?
wrist joints: condyloid, ellipsoid, and saddle joints
what does 3 degrees of freedom mean?
the joint is triaxial and the segment moves in 3 planes around 3 axes
what joints are triaxial with 3 DF?
ball and socket joints
what are kinematic chains?
series of articulated segments linked together (ie. pelvis, thigh, knee, calf, ankle, foot)
a combo of several joints uniting body segments
what is the open kinematic chain (OKC)?
distal segment (hand and foot) is not fixed to the ground so it is free to move
does the OKC provide more mobility or stability?
mobility
can segments move independent of each other in the OKC?
yes!
what is the closed kinematic chain (CKC)?
the distal segment is fixed to the ground/unmoving object so it is not free to move, but the proximal segments can
can you move segments independent of each other in the CKC?
no
does the CKC provide more mobility or stability?
stability
what is arthrokinematics?
motion that occurs b/w the articular surfaces of joints
what are the 3 types of joints?
synarthrosis, amphiarthrosis, and diarthrosis
what are synarthrodial joints?
fibrous joints that are immovable
what are the 2 types of synarthrodial joints?
syndesmosis and gomphosis
what is the main job of synarthrodial joints?
to provide stability
what is the syndesmosis joint?
2 parallel bones connected by strong ligaments or membranes
the tibia and fibula
what is a gomphosis joint?
the skull sutures
what are amphiarthrodial joints?
cartilaginous joints with fibrocartilage
what is the main job of amphiarthrodial joints?
mobility and stability
what are some examples of amphiarthrodial joints?
pubic symphysis, IV joints
what are diathrodial (synovial) joints?
the most common type of joints that provide provide moderate to extensive mobility
what are some of the components of a diathrodial joint?
synovial fluid filled cavity, cartilage, ligaments, bursa, joint capsules
what are some examples of diarthrodial joints?
gh joint, knee, ankle, fingers
how are diarthrodial joints classified?
by the # of axes about which joints can move (corresponds to DF)
what are the classifications of diarthrodial joints?
uni, bi, and triaxial joints
most synovial joints are ___ in shape
ovoid
what is a sellar shaped joint surface?
has both convex and concave surfaces
what is the point of the concave convex relationship?
to improve the congruency of bones and increased the surface area of bone contact to help guide motions
what actions occur in the sagittal plane around the medial-lateral axis?
flexion/extension
what motions do hinge joints allow?
flexion/extension
what motions do pivot joints allow?
pronation/supination
what is a condyloid joint?
one side has mostly spherical convex surface enlarged in one dimension paired with a very shallow concave surface
what are some condyloid joints?
knuckles, knees
what is an ellipsoid joint?
convex surface flatter than condyloid joints paired with deeper concave surface
what is an example of an ellipsoid joint?
the radiocarpal joint at the wrist
what is a saddle joint?
each surface has both concave and convex surfaces
what are some examples of saddle joints?
CMC joints of the thumb, SC joint, talocrural joint
what is a ball and socket joint?
convex surface with concave cup
what are some examples of ball and socket joints?
hip and shoulder
what are the 5 arthrokinematics motions?
roll, slide (glide), spin, distractions (traction), and compression
what is the roll motion?
rotary motion where multiple points along one rotating articular surface contact multiple points on another articular surface
a rocking chair motion
what is the slide (glide) motion?
linear motion where a single point on 1 articular surface contacts multiple points on another articular surface
a tire skidding on ice
what is the spin motion?
rotary motion where a single point on 1 articular surface rotates on a single point on another articular surface
a draddle spinning
what is distraction?
pulling of join surfaces directly away from each other usually done by a force applied perpendicular to each other
why don’t you want pure rolling motion?
it would cause a dislocation
normal knee motion requires a combination of _____, _____, and _____
rolling, sliding, spinning
what is the concave convex rule?
when the convex surface is moving on the concave surface, the roll and glide are in opposite directions
when the concave surface is moving on the convex surface, the roll and glide are in the same direction
when the concave surface is moving on the convex surface, the roll and glide are in the ____ direction
same
when the convex surface is moving on the concave surface, the roll and glide are in the ____ direction
opposite
are functional axes of rotation fixed?
no, they move during motion
most joint axes are ____ to the long axis of the bone
oblique (at a slight angle)
what is the closed packed position of a joint?
there is max surface contact of a joint
are the ligamentous structures taut in the closed or open packed position?
closed packed position
is it easy or difficult to distract a joint in the closed packed position?
difficult
t/f: there is a lot of accessory motion in the closed packed position
false
where in the ROM is the closed packed position usually?
at the end of the range or near its end
what is the open packed position of a joint?
the joint position where the capsuloligamentous tissues are slack and the joint surfaces don’t fit congruently
is there increased or decreased friction in the open packed position?
decreased
t/f: the open packed position allows for greater motion
true!
where is the ROM is the open packed position usually?
mid range
why is the open packed position clinically important?
the open packed position is preferred by patients and allows for joint mobilization with minimal friction
torque is ____ motion occuring about an axis
rotary
what are the 5 variables that determine and describe motion?
type, location, magnitude, direction, and rate of motion and rate of change
what are the 2 types of motion?
linear and rotary
what are the units for linear motion?
meters or feet
what are the units for rotary motion?
degrees
what is magnitude?
the distance
what is positive motion on the x axis?
towards the right
what is positive motion on the y axis?
upward
what is positive motion on the z axis?
forward
what is velocity?
rate at which motion occurs measured in ft/sec, m/sec, or degrees/sec
what is acceleration?
rate at which velocity changes measured in m/s ^2 or degrees/s^2
what is positive acceleration?
moving faster
what is negative acceleration?
slowing down
what are the 2 dimensions of forces?
direction and magnitude
what is the difference between weight and mass?
weight is influenced by gravity, but mass remains stable as it is just the amount of matter in an object that is not influenced by the effects of gravity
if 2 forces of the same magnitude are acting in opposite direction will there be movement?
no, it will be in a state of equilibrium
what is moment?
force acting at a distance from the axis
what is the equation for moment?
M = f x d
where M=moment
f=force
d=moment arm
what is the moment arm?
the perpendicular distance from the force vector to the axis of motion
distance from the axis to the muscles insertion or resistance
changing the length of the lever arm changes what about motion?
the forces required
why is is easier to flex the hip with the knee flexed also?
when the knee is flexed, it creates a shorter moment arm and therefore a decreased moment
does an increased moment arm or a decreased moment arm make exercises more difficult?
an increased moment arm
what is newton’s law of inertia?
a body at rest and a body in motion will stay that way until acted upon by a force
what is newton’s law of acceleration?
proportionate to the magnitude of the net forces acting on it and inversely proportionate to the mass of the body
acceleration is inversely related to mass
what is newton’s law of action-reaction?
for every force, there’s an equal and opposite reaction force
what a resultant force?
the sum of the forces acting on a segment
the simplest force that produces the same effect as all the forces acting on body
how to you create a resultant force
connect the head of a force to the tail of another and so on with all forces, then connect the first tail to the last head in a straight line
what happens if the traction force is greater than the force that a soft tissue can take?
dislocation
what is a 1st class lever?
the axis of rotation is between the force and resistance arm
seesaw
what is an example of a 1st class lever in the body?
the head and neck extensor muscles
what a is a 2nd class lever?
the axis of rotation is at one end with the force arm longer than the resistance arm
wheel barrel
what is an example of a 2nd class lever in the body?
the calf producing torque needed for tip-toeing
what is a 3rd class lever?
the axis of rotation is at one end and the resistance arm is longer than the force arm
what is an example of a 3rd class lever in the body
the biceps doing a bicep curl
what is the most common type of lever in the body?
3rd class levers
what is mechanical advantage?
the force arm / resistance length
if the force arm length is greater than the resistance arm length, is there a mechanical advantage (MA>1)?
yes!
if the force arm length is equal to the resistance arm length is there a mechanical advantage (MA>1)?
no, MA=0
what is the role of 1st class levers?
balance and stability
t/f: 1st class levers have varying force arm and resistance arm lengths, so there is no fixed ratio for MA
true!
what is the role of 2nd class levers?
power and deceleration
in 2nd class levers the displacement of _____ will always be < displacement of ____
resistance, force
in 2nd class levers, the ____ arm > _____ arm
force, resistance
what is the role of 3rd class levers?
producing speed
t/f: in 3rd class levers, small changes in muscle length create large angular displacements
true!
in 3rd class levers, the displacement of _____> displacement of _____
resistance, force
why is performing a bicep curl with a weight closer to the elbow easier than performing a bicep curl with a weight in the hand?
because with the weight closer to the axis of rotation, the resistance arm becomes shorter.
does a shorter or longer resistance arm make exercises easier?
shorter resistance arm
what is internal moment arm?
the perpendicular distance from the axis to the muscles insertion (like the force arm)
what is external moment arm?
the perpendicular distance from the axis to the external force or the body’s COM (like the resistance arm)
what is torque?
force applied around an axis that produces rotational joint motion
what is the equation for torque?
T = F x d
what is internal torque?
product of internal force (muscle) and internal moment arm
what is external torque?
product of external force (gravity) and external moment arm
what is a tangential force?
compression/distraction
at 90 degrees of flexion there is only _____ force
rotational
at about 120 degrees, there is ____ and ____ forces
rotational and distraction
in a half squat, would the compressive forces b/w the patella and femur be more or less than in a full squat?
less bc the resultant force is smaller
there is max resistance force when the segment is ____
horizontal
the ____ the IMA, the _____ the rotational motion by the muscle at the joint
greater, greater
if the IMA is > resistance arm, there is more or less angular motion?
more
traction is created by what kind of forces?
tangential
at 90 degrees of flexion, are there tangential forces?
no
at what angle of flexion is there the least amount of compressive forces?
90 degrees
at greater than 90 degrees, what is the ratio of rotational and traction forces?
50/50
at less than 90 degrees, is there more tangential or rotational forces?
rotational forces (flexion)
the patella creates a larger or smaller IMA for the quad tendon?
larger
what is the role of a pulley?
to provide varying resistance w/in a joint’s ROM as it changes the direction and magnitude of forces
if the leg is straight out using a pulley system, are there more tangential or rotational forces
both, its 50/50 of each
what is the role of anatomical pulleys?
to change the course of tendons and increased the MA
what are 2 examples of anatomical pulleys in the body?
the peroneus longus around the lateral malleolus and the quad tendon over the patella
what is pressure?
force per unit of area
what happens with excessive pressure?
caluses, pressure ulcers, stress fractures, bone spurring, etc
what are some ways to reduce pressure?
increase the surface area
traction
reducing the magnitude of the force
reducing the amount of time the pressure is applied
during stretching, should external forces be applied proximally or distally to prevent high stress on tissues?
proximally
how can we reduce stress in injured joints?
sling, splint, gravity eliminated positions, abduction of the shoulder in supine if gh joint is stress, and water activities
what is the COG/COM?
theoretical point about which an object is balanced
what is the origin of gravity’s force vector?
the COG/COM
does the COG/COM change with movement?
yes!
in adults, where is the COG located?
anterior to S2
t/f: male COG tends to be higher than that of females
true bc females tend to have wider hips than males
what is the COG of the head, arms, and trunk?
anterior border of T11 and just below the xiphoid process of the sternum
(literally don’t know if this is dif from body COG so sorry if this doesn’t make sense bc I don’t get it either)
t/f the weight of the upper body is about 60% of the entire body’s weight
true!!
what is the line of gravity?
the vertical line downward from the COM
what is the BOS?
the area within points of contact of the body and any object an individual relies on for support
when is the body stable?
when the COG is within the BOS and the line of gravity in through the center of the BOS
does a wider BOS or a smaller BOS provide more stability?
a wider BOS
what is wrong with the stoop position?
the COG is not over the BOS, the extensors (postural muscles) have to work harder so you are more prone to back injuries
why is the squat position advantageous?
the COG is within the BOS, the muscles don’t have to work as hard bc the quads have more type 2 fibers for more force generation
what are the 3 isotonic contractions?
isometric, eccentric, and concentric
what is an isometric contraction?
contraction with no change in muscle length
what is a concentric contraction?
contraction against gravity where the muscle is getting shorter
is concentric contraction positive or negative work?
positive work because motion is produced by the muscle
what is an eccentric contraction?
contraction with gravity where the muscle gets longer
is eccentric contraction positive or negative work?
negative work because the external force is responsible for motion done by the muscle
what is isokinetic contraction?
constant rate of movement (constant velocity=0 accelerartion)
does the body really ever generate isokinetic contraction?
no, it is usually simulated by a machine like a Biodex)
in isometric contractions muscle torque __ load torque
=
in concentric contraction muscle torque __ load torque
>
in eccentric contraction muscle torque __ load torque
<
when is predicting muscle function simple?
proximal attachment is stabilized
distal attachment moves towards proximal (often OKC)
distal segment moves against gravity (concentric)
acceleration activity
3rd class lever
muscles provides moving force
how do muscles often function?
proximal attachments move toward distal attachments (often CKC)
distal segment motion may be assisted by gravity (eccentric) deceleration activity
2nd class lever
muscles provide resistance force
what are type 1 muscle fibers?
slow twitch, fatigue resistance, small amount of forces
what are type 2a muscle fibers?
fast twitch, oxidative, mix of type 1 and 2
what are type 2b muscle fibers?
fast twitch, glycolytic, least fatigue resistance fibers that are good for explosive movements and large force generations
as you age, there is a preferential loss of what type of muscle fibers?
type 2
what happens with preferential loss of type 2 fibers?
loss of force generating capabilities
what are postural muscles?
muscles that maintain posture
what type of fibers are postural muscles?
type 1
what are some examples of postural muscles?
trunk extensors, abdominals, hamstrings, quads, glutes, cervical flexors, delta, soleus, etc
what are phasic muscles?
muscles that contract rapidly and generate a lot of fibers
what type of fibers are phasic muscles?
type 2
what are some examples of phasic muscles?
gastrocs, biceps, upper extremity flexors, etc
what is an agonist?
the prime mover
what is an antagonist?
muscle that produces opposite actions of the prime mover and resists movement if activated
what is a synergist?
muscle that helps the agonist action
what are the 2 types of synergists?
stabilizers and neutralizers
what are stabilizers?
muscles that stabilize joints for distal movement and usually act isometrically
what are neutralizers?
muscles that stop unwanted movement of agonists
what is co-contraction?
agonist and antagonist acting together to stabilize a limb so that the distal movement can occur
usually of the proximal joint
what are the 8 factors that affect the muscles strength/performance?
- muscle size
- architecture of muscles fibers
- passive components of the muscle
- physiological length of the muscles/length-tension relationship of the muscle (covered in 503)
- moment arm length
- speed of muscles contraction (covered in 503)
- active tension (covered in 503)
- age and gender
what is the role of shorter muscles?
stability
what is the role of longer muscles?
mobility
what is muscle length associated with?
speed of motion
what is muscle width associated with?
strength
width is fibers in ____
parallel
increase in width _____ cross sectional area
increases
t/f: parallel fibers produce greater strength
true!
what is hypertrophy?
adding fibers in parallel so muscles get bigger not longer
what is atrophy?
muscle loses its bulk often due to aging or inactivity
