Midterm Flashcards
What is kinesiology?
The study of human movement
What is kinematic?
A branch of mechanics that describes motion of a body in space without regard to forces or torques
What are the two types of motion?
- Translation
- Rotation
What is translation motion?
Linear motion - all parts move in a straight line
What is rotation motion?
Angular motion - body spins about an axis
In the human body, what translates through space during movements?
The center of mass (where mass is exactly centered)
Where is the center of mass located?
In front of S2 sacral segment, near bellybutton
How do muscles create angular movements?
Muscles rotate the limb to create angular movement of joint
What is a pivot point?
The axis of rotation, point where motion of rotating body is zero
How can movement of body be describes?
Active or passive
What is active movement?
Movement that is caused by stimulated muscle contractions
Volitional (conscious) control
What is passive movement?
Movement that is caused by other sources like external forces (gravity, push/pull) or tension in stretched connective tissue (internal forces)
What is osteokinematics?
The motion of bones relative to the 3 cardinal planes
What are the three cardinal planes?
- Sagittal
- frontal
- transverse
What are the planes of motion in relationship to? (Reference frame)
Anatomical position
What does the sagittal plane divide? What is its axis?
- Divides the body from left to right segments
- medial to lateral axis
What does the frontal plane divide? What is its axis?
- divides body from left to right
- anterior-posterior axis
What does the transverse plane divide? What is its axis?
- divides the body into top and bottom segments
- vertical axis
What is the axis of rotation?
point at which the bones rotate around the joint and perpendicular to the plane
Which partner does the axis of rotation pass through?
Convex partner
What motions typically occur in sagittal plane?
flexion, extension, dorsiflexion, plantarflexion
What motions occur in the frontal plane?
abduction, adduction, lateral flexion
What motions occur in the horizontal plane?
medial (internal) rotation, lateral (external) rotation
What are degrees of freedom and how many are allowed at a joint?
- the number of independent directions of movements allowed at a joint
- joints can have up to 3 degrees of freedom, in all 3 planes of motion
What are accessory movements? In what directions to they occur?
- slight passive translatory movement of the bones in the joint
- occurs in A/P, M/L, S/I directions
What is proximal on distal joint movement?
- proximal segment rotates on fixed distal segment
- ex. squatting; push-up
What is distal on proximal joint movement?
- distal joint segment rotates on fixed proximal segment
- ex. knee extension while sitting; elbow flexion
Anatomical position
generally agreed upon reference position of the body used to describe location and movement of its parts
- a person standing full upright, looking forward, arms resting by side, forearms supinated
What is external force?
push or pull produced by sources located outside the body
- gravity, physical contact
What is a segment?
any portion of the body or limb
What is arthrokinematics?
the motion that occurs between articular surfaces of joints
What are the fundamental movements between joint surfaces?
- roll
- spin
- slide
definition of roll
when multiple points along one rotating articular surface contact multiple points on another surface
- ex. like a tire moving on the ground
definition of slide
a single point on one articular surface contacts multiple points on another articular surface
- ex. a tire (non-rotating) skids across a stretch of pavement
definition of spin
a single point on one articular surface rotates on a single point of another articular surface
- ex. a toy top spinning
When does the roll and slide occur in the same direction?
concave on convex
What is an example of same roll and slide direction?
elbow flexion (the concave olecranon of the ulna moves on the convex humerus)
When does the roll ad side occur in the opposite direction?
convex on concave
What is an example of opposite roll and slide direction?
shoulder abduction (the convex head of humerus moves in concave glenoid fossa)
When does spinning arthrokinematics occur?
when the longitudinal axis of the moving bones intersects the surface of its partner at a right angle
What are examples of spin arthrokinematics?
- internal and external rotation of the humerus at 90 deg. abduction
- ball and socket joints
- forearm pronation at the radiohumeral joint
When are all 3 arthrokinematics motions combines?
- when the joint will slightly spin to lock the joint
- flexion/extension of the knee, you get a spin of the tibia to lock the joint
What is a closed packed position of a joint?
the position of max congruency, the articular surfaces are tightly packed together
When does a closed packed position occur?
at the end or near the end of a range of motion
How many positions in a joint are close packed?
one
What is a loose packed position of a joint?
- all other positions of a joint other than close packed
- the ligaments are slackened and allow for accessory movement
When does loose packed position occur?
in midrange of range of motion
What is resting position of a joint?
- most loose-packed position
- most comfortable when joints are injured or swollen
- somewhere in midrange ROM
What is kinetics?
a branch of mechanics that describes the effect of forces on the body
What is a force?
a push or pull that can produce, stop, or modify a movement
What is force also known as when acting on the body?
a load
What is torque?
force around an axis
What are example of force?
- tension
- compression
- bending
- shear
- torsion
- combined
- unloaded
Difference between health and damaged tissues in terms of force
- healthy tissues can withstand force and maintain their structure
- damaged or weak tissues are more susceptible to loads and strains
What is the ratio of stress/strain?
stiffness
What is the elastic region of stress strain curve?
linear region where there is still stretching, but it isn’t breaking
What is the plastic region of stress strain curve?
nonlinear region where deformation can occur
- tissue can reach failure point and tear/break
What is the yield point of stress strain curve?
- complete failure of tissue
- the tissue doesn’t return to normal and is deformed
What is viscoelasticity?
property of material that changes along the stress strain curve as a function of time
- ex. taffy, slowly stretch, if you pull very quickly it won’t do anything
definition of creep
a progressive strain of a material when exposed to a constant load over time and eventually can break
How does rate of loading impact stress strain curve?
if you’re loading something very fast this has more resistance to deformation
explain the stress strain curve with examples
- taffy example: if you slowly start to stretch taffy, you are able to pull on it and create a bridge of taffy between your two hands. as you pull your hands apart, this is the plastic elastic region. when the bridge of taffy gets very thin, you enter the plastic region where the taffy is likely to break. finally you hit the yield point where the bridge of the taffy breaks and you’re left with taffy split in half
What are internal forces?
forces produced from structures within the body and may be active or passive
What are external forces?
forces produced by sources outside of the body
What are examples of active and passive internal forces?
- active forces are muscles
- passive are connective tissue (usually restrain motion)
What are examples of external forces?
- gravity (wind resistance, friction)
- physical contact (weight on something)
What is a free body diagram?
an illustration of forces acting on a segment of the body
What are components of a free body diagram?
- vector
- point of application
- angle of insertion
What is the most effective angle to move an object?
90 degrees
What is a vector?
an arrow that depicts both magnitude and direction
What is point of application?
where the base of the arrow contacts the body (where muscle inserts into bone)
What is angle of insertion?
angle between the tendon of the muscle and the bone insertion
What is static linear equilibrium?
the sum of all forces acting on the segment is zero because forces are balanced
How many times greater is internal than external force and what does this mean?
- 3x greater
- to hold your forearm at 90 deg., your bicep has to work 3x as hard as gravity
What is the equation for work and torque
work = force x distance
torque = force x resistance
What is a concentric muscle activation?
occurs as a muscle produces a pulling force as it contracts (shortens) usually an acceleration
What is an isometric muscle activation?
occurs when a muscle is producing a pulling force when maintaining a constant length
What is an eccentric muscle activation?
- occurs as a muscle produces a pulling force as it is being elongated by a more dominant force (lengthening)
- usually a deceleration
What plane does gravity minimize?
transverse plane
Agonist
muscle of muscle group that is most closely related to the initiation and execution of a particular movement
antagonist
muscle or group that is considered to have opposite action of agonist
synergist
- muscle that cooperate during a movement
- some muscles can neutralize unwanted movement to create a particular movement
- helps, holds stable
force couple
when 2 or more muscles simultaneously produce forces in different linear directions and results in rotary direction
example of force couple
- upper and middle traps with serratus anterior working on scapula to pull into upward rotation
- upper trap pulls up on acromion, middle pulls down on spine, serratus pulls on inferior angle
What is a lever? what are the components?
- machine that has a rod suspended across a pivot point; converts linear force into rotary torque
- has axis, muscle force/effort resistance (AER)
What is a first class lever? Example?
has axis of rotation between the muscle effort and resistance
ex. seesaw
What is a second class lever? Example?
has an axis of rotation at one end and resistance in the middle
ex. going on tip toes
What is a third class lever? Example?
has an axis of rotation at one end and effort in the middle
ex. biceps curl
What is mechanical advantage?
the ratio of the internal moment arm to the external moment arm (leverage)
What are the acronyms for levers?
- EAR
- ARE
- REA
Line of force
direction and orientation of a muscle force
moment arm
perpendicular distance between axis of rotation and the line of force
stiffness
ratio of stress (force) to strain (elongation) within an elastic material
contrast the fundamental difference between kinematics and kinetics
- kinematics describes motion but doesn’t look at or include force/torque
- kinetics describes motion by examining the impact of the torque/force on the body
contrast the difference between force and torque
(use each term to describe an aspect of a muscle’s contraction relative to a joint)
- force is a push or a pull in a straight line that can stop or start a motion
- torque is a force that occurs in a rotation around an axis
- a contraction force produced by the elbow flexor muscles can create compression within the elbow joint. the torque produced by the elbow flexor muscles can produce angular acceleration of the elbow which brings your hand to your mouth
define and contrast internal and external torque with an example
- internal torque is a torque produced around a joint by an internal force (muscle contracting)
- external torque is a torque produced around a joint caused by an external force (gravity)
- when opposing internal and external torques about a joint are equal, the joint is often described as being in static rotary equilibrium. if the internal and external torques were not equal, the joint would accelerate in the direction of the larger torque
