Test One Flashcards
Two most important principles in kinesiology
Mobility
Stability
4 aspects of movement
Mechanical (biomechanics)
Neural (motor control)
Cardiovascular
Psychological
Biomechanics
Study of mechanics applied to posture and movement
Statics
Study of forces acting on a body at rest or at equilibrium
Dynamics
Study of forces acting on moving bodies
Biomechanics is necessary to understand
Posture
Movement
Mechanical basis of dysfunction
Mechanical rationale for interventions
Kinematics
Study of motion without regard to the forces that causes it
Kinetics
Study of motion under the influence of forces
Displacement
Motion- change in position over time
5 kinematic variables to describe displacement/ motion
Type of displacement Location in space of displacement Direction of displacement of segment Magnitude of displacement Velocity or acceperatoon
Acceleration
Rate in change of velocity
Can indicate increasing velocity (acceleration)or decreasing velocity (deceleration)
Types of displacement
Translatory motion(linear)
Rotary (angular)
General (curvilinear)
General (curvilinear) motion
Combination of linear and rotary motion: object is rotating around an axis while also being translated
Most human motion is this type
Axis of rotation
A line perpendicular to the plane of motion
X axis is coronal
Y axis is vertical
Z axis is anteroposterior
Degree of freedom
Options of movement of a segment
Sagittal plane
Moves around the x axis
Transverse plane
Moves around y axis
Frontal plane
Moves around z axis
How to describe direction of displacement
Using positive or negative values, clockwise or counterclockwise Human motion: Flexion extension Abduction adduction Medial and lateral rotation
Magnitude of angular motion
Range of motion
Magnitude of translatory motion
Distance
Speed
Displacement per unit of time regardless of direction
Velocity
Distance travelled in unit time in given direction
M/sec
Ft/sec
Force vectors have 4 components
Magnitude
Direction
Line of action
Point of application
Moment
The force acting to rotate a body around an axis
Tends to cause or change rotary motion
Effector a rotary force is dependent on
Magnitude of the force
It’s moment arm; the perpendicular distance from the line of action to the axis of rotation
Moment arm
Perpendicular distance from the line of action to the axis of rotation
Moment
Also known as torque
Torque=force x moment arm
When force changes direction it’s moment arm changes in length which affects the torque
Force of gravity
Gravity has all of the characteristics of a force
Magnitude- depends on mass of object
Direction- always acts downward
Line of action- always vertical; line of gravity
Point of application- center of gravity
Center of gravity
Point at which the total mass of a body is considered concentrated
The body is balanced in all planes
In a symmetrical object the COG is geometric center
In an asymmetrical object the COG is toward the heavy end
Stability
The ability of an object to prevent being unbalanced
What affects stability
The base of support- the area between feet or assisting device. The larger the better
Placement of the line of gravity relative to the base of support. The more central the better
Height of the center of gravity- lower cog the more stable. Takes more to displace a lower COG
Mass of the object- heavier the object the more stable
Newtons law of mechanics
Basis for the study of kinetics
Laws that govern the behaviors of forces and the bodies they act on
3 laws are not isolated from each other they are integrated
Newtons law of inertia
A body stays at rest or in uniform motion unless acted on by an unbalanced or outside set of forces
Can change or create motion if inertia is overcome
Inertia
The resistance of an object to motion or change in motion
What kind of motion does inertia apply to?
Linear and rotary
With linear motion inertia is dependent on:
Mass of the object
Inertia and rotary motion is dependent on
Mass of the object
Distance of the mass from the axis of motion; the closer the mass, the less the inertia
Mass is constant inertia is not
Newtons law of acceleration
When a force acts on an object the object accelerates in direct proportion to the magnitude of the force applied and in inverse proportion to the mass
Acceleration=force/mass
Newtons law of reaction
For every action there is an equal and opposite reaction
Composition of forces
This determines if unbalanced forces on a segment exist
This will determine if the segment is in motion or rest
This will determine type and direction of motion
Linear force system
2 or more forces act on the same segment in the same plane and in the same line
Forces can be added together and result in a single resultant vector
Concurrent force system
2 or more forces meet at a common intersection but their action lines differ
Creates resultant force
Force components
A torque around a joint does not only cause rotation around the axis unless applied at 90 degrees
A torque can be resolved into what 2 components
Perpendicular (rotary) Fy
Parallel (translatory) Fx
Parallel force systems
Two parallel forces acting in the same object at different locations
General force system
A force system that does not fit into one of the other categories
First class lever
Axis is between the force line and resistance line
Second class lever
Resistance line is between force line and axis
Third class lever
Force line is between resistance line and axis
Mechanical advantage
Ratio of the muscle moment arm and the resistive moment arm
Force arm/ resistance arm
If >1 considered to be an efficient mechanical system
If <1 inefficient
Mechanical advantage in lever systems
1st- depends
2nd- good
3rd- poor
Friction
Force created between 2 contacting surfaces that tend to rub or slide past one another
Magnitude of friction depends on
Texture of both surfaces
How much force is pressing the 2 surfaces together
Friction prevents or resists motion
It is the greatest just immediately before the object moves
Force couple
Two or more forces that create a single motion
Work
Transfer if energy resulting in motion or displacement
Force x distance
Measured as joules
Positive work
Force and movement in same direction
Negative work
Force and movement in opposite direction
Energy
Capacity of a body to perform work
Kinetic energy
Energy of motion
Potential energy
Stored energy
Power
Rate of work production
Expressed in watts
Work/time
Open chain
One end of segment is free to move in space
Closed chain
Both ends of segment or set of segments are constrained
Joint design
Form follows function
Balance between stability and mobility
Analysis of the anatomy of the joint/structure
In the body, function influences form
The body responds to loading by adapting appearance and composition
Mechanotherapy
Clinical application of mechanotransduction
Therapeutic exercise is prescribed to promote repair or remodeling of injured tissue
Tendon can achieve normalized structure after injury when treated with exercise
Continued research needed for determining the ideal loading conditions
Connective tissue components
Cells
Extracellular matrix
Extracellular matrix
Part outside cells Almost entire volume of the tissue Determines the function Contains mainly proteins and water Fibrillar component And interfibrillar component
Fibrillar component of extra cellular matrix
Collagen (strength) and elastin-structural protein
Interfibrillar component of extra cellular matrix
Water
Glycoproteins and proteoglycans (pg)
When a force acts on an object what does it produce?
Deformation
Tensile load: elongation
Compression load: compression
Stress
Force per unit area
Dealing with tensile load
Strain
Elongation per unit length in response to tensile load
Change in length/original length
Expressed as a %
Young’s modulus
Modulus of elasticity
Represented by linear portion of curve between point A and B
A measure of the material’s stiffness
Inverse is compliance
Viscoelasticity
Combination of elasticity and viscosity
Makes behavior time dependent, rate dependent, and history dependent
Tissues are affected by the fluid in the structures
Viscosity
Resistance to flow
Creep
Force applied is the same over time and the deformation increases
Stress- relaxation
If tissue is stretched to a fixed length over time, the force required to keep that length would decrease
Hysteresis
The loading and unloading does not follow the same path due to energy lost
Strain- rate sensitivity
When load is applied rapidly the tissue is stiffer
Tendons attach
Muscle to bone
Ligaments attach
Bone to bone
May blend with joint capsule
Dense regular CT
Densely packed
Fiber bundles parallel
Withstand tensile forces
What determines tendon/ligament properties?
Combination and proportion of collagen and elastin fibers
Entheses
Tendon and ligament attachment to the bone
Tendon and ligament attach directly to bone via
Fibrocartilage
Tendon and ligament attach indirectly to bone via
Fibrous attachment
Effect of rate of force of application on mechanical properties of tendons and ligaments
Become stiffer with increased rate of application
Tendon load can be increased in 2 ways
Increase the external load
Increase the speed of movement
Progressive load of the Achilles’ tendon- 4 ways
Sitting heel raise
Two legged heel raise
One legged heel raise
Eccentric overload
Effect of temperature on mechanical properties of tendons and ligaments
Increased tissue temperature=
Decreased stiffness
Increased creep and relaxation
Decreased tissue failure limit
Effect of aging on mechanical property of tendons and ligaments
Tensile strength increases during childhood
Maximal tensile strength at skeletal maturity
Declines gradually during adulthood- can be minimized through exercise
Ligaments are what kind of organs
Sensory
Proprioception
Kinesthesia
What can ligaments cause?
Recruitment or inhibition of muscles
Eg activate cocontraction to increase joint stability
SAID principle
Specific adaptation to imposed demand
Immobilization
Decreases tensile strength and stiffness
Causes contractures
How can the effects of immobilization be minimized?
If tendon or ligament is elongated when immobilized
General effect of exercise on tendon and ligament strength
Increases circulation
Can minimize loss of strength associated with aging or injury
Bone
Hardest form of CT
Bone function
Serves as framework for body
Serves as levers for muscle action
Protect viscera
Main misconception about bone
That it’s a static tissue
Cancellous bone
Soft bone- highly vascularized
Inner layer
Forms thin plates (trabeculae) in lines of stress
Cortical bone
Hard bone
Very dense
Outer layer
Covered by periosteum
Growth plates
Epiphysis
Wolff’s law
Structure follows functionn
% turnover in cancellous bone per year
25%
%turnover in cortical bone per year
3%
What part of the body weight of compression does the femur sustain when standing on one leg?
1.8-2.7 times the body weight
Why is the compression On the femur higher than the body weight when standing on one leg?
Body weight and muscle force
Bending forces on the femur when loaded in standing
Offset loading
Compression medially
Tension laterally
Anisotropy
Bone has different mechanical properties in different directions
Changes in mechanical properties of bones with aging
> 35 years old: gradual decrease in resistance to fracture
Changes in mechanical properties of bone with activity
Increase activity: increased density
Force
A push or pull Normally from physical contact Exception is gravity Mass x acceleration Tends to cause change or change motion Cause/effect relationship: every motion is caused by a force. A force does not always cause motion
Main function of cartilage
Distribute joint loads over as large an area as possible.
Allow contact and movement between 2 bony surfaces with minimal friction and wear
Primary components of cartilage
70-85% water
Also proteoglycans, glycosaminoglycans, collagen, lipids, chondrocytes
The importance of glycosaminoglycans (gag) in cartilage function
Molecules that imbibe water
Allow for nutrient delivery in ct
Water imbibing swells tissues and gives them stiffness like a water balloon.
Helps disperse repetitive forces
With aging decrease gag replacement: increase tissue breakdown
Hyaline cartilage
Found in synovial joints
Extremely low friction- 6x less than skating on wet ice
Fibrocartilage
Repair material
Higher friction than hyaline cartilage
Elastic cartilage
Maintains shape of structures (ear)
Cartilaginous nutrition
Joint cartilage is mostly avascular
Only the deepest portions are fed by capillaries from subchondral bone
Rest of cartilage is fed via diffusion and other means of transport from synovial fluid
Requires compression/release of cartilage (pump mechanism)
Weight bearing, joint motion, muscle contraction
How is cartilaginous compressibility affected by rate of loading
Rapid loading- cartilage becomes stiffer
Biphasic model of cartilage loading
Fluid pressure sustains a lot of the loading initially
If loading continues, the solid matrix sustains more of the load
What happens to the fluid content of cartilage when subjected to a constant load?
Undergoes creep
How are compression of cartilage and shear force related in creating cartilage failure
Compression causes shear forces at cartilage bone interface
Mechanical factors that can cause osteoarthritis
Obesity
Repetitive loading
Joint instability
Rapid loading (impulse loading)
High loading sports and cartilage
Increased chance of osteoarthritis but mostly related to injury
ROM exercise and cartilage
Increased fluid flow in and out of cartilage
Moderate exercise and cartilage
Increased gag count therefore increase tensile strength
Joints serve two basic functions
Provide mobility and stability
Basic rule of joints
The more mobile a joint is, the less stable a joint is
Diarthroses
Synovial joints
Allows free movements
Synarthroses
Non synovial joints
Fibrous joints
Sutures- when fused, synostosis
Gomphoses
Syndesmoses
Cartilaginous joints
Symphyses- directly joined by fibrocartilage
Synchrondrosis- connected by hyaline cartilage
2 layers of joint capsule
Stratum fibrosum
Stratum synovium
Stratum fibrosum
Poor vascularization
Rich innervation
Function- position and movement sense
Stratum synovium
Rich vascularization
Poor innervation
Produce synovial fluid
Diarthrodial classification
Uniaxial
Biaxial
Triaxial
Uniaxial
Hinge joints
Pivot joints
Biaxial
Condyloid
Saddle
Triaxial
Plane joints
Ball and socket joints
Hyper mobile
Rom exceeds normal
Hypomobile
Rom less than normal
Contracture
No mobility
Osteokinematics
Rotary movement of the bones in space during physiological joint motion
Flex ext
In the sagittal plane
Around the x axis
Accessory motion
Motion of the joint surfaces in relation to another
Accompany voluntary osteokinematics motion but cannot be voluntary isolated
Terms used are roll, slide, spin
Convex-concave rule
Convex surface move on fixed concave surface then roll and glide occur in opposite directions
Concave surface move n fixed convex surface then roll and glide occur in same direction
Main function of cartilage
Distribute joint loads over as large an area as possible.
Allow contact and movement between 2 bony surfaces with minimal friction and wear
Primary components of cartilage
70-85% water
Also proteoglycans, glycosaminoglycans, collagen, lipids, chondrocytes
The importance of glycosaminoglycans (gag) in cartilage function
Molecules that imbibe water
Allow for nutrient delivery in ct
Water imbibing swells tissues and gives them stiffness like a water balloon.
Helps disperse repetitive forces
With aging decrease gag replacement: increase tissue breakdown
Hyaline cartilage
Found in synovial joints
Extremely low friction- 6x less than skating on wet ice
Fibrocartilage
Repair material
Higher friction than hyaline cartilage
Elastic cartilage
Maintains shape of structures (ear)
Cartilaginous nutrition
Joint cartilage is mostly avascular
Only the deepest portions are fed by capillaries from subchondral bone
Rest of cartilage is fed via diffusion and other means of transport from synovial fluid
Requires compression/release of cartilage (pump mechanism)
Weight bearing, joint motion, muscle contraction
How is cartilaginous compressibility affected by rate of loading
Rapid loading- cartilage becomes stiffer
Biphasic model of cartilage loading
Fluid pressure sustains a lot of the loading initially
If loading continues, the solid matrix sustains more of the load
What happens to the fluid content of cartilage when subjected to a constant load?
Undergoes creep
How are compression of cartilage and shear force related in creating cartilage failure
Compression causes shear forces at cartilage bone interface
Mechanical factors that can cause osteoarthritis
Obesity
Repetitive loading
Joint instability
Rapid loading (impulse loading)
High loading sports and cartilage
Increased chance of osteoarthritis but mostly related to injury
ROM exercise and cartilage
Increased fluid flow in and out of cartilage
Moderate exercise and cartilage
Increased gag count therefore increase tensile strength
Joints serve two basic functions
Provide mobility and stability
Basic rule of joints
The more mobile a joint is, the less stable a joint is
Diarthroses
Synovial joints
Allows free movements
Synarthroses
Non synovial joints
Fibrous joints
Sutures- when fused, synostosis
Gomphoses
Syndesmoses
Cartilaginous joints
Symphyses- directly joined by fibrocartilage
Synchrondrosis- connected by hyaline cartilage
2 layers of joint capsule
Stratum fibrosum
Stratum synovium
Stratum fibrosum
Poor vascularization
Rich innervation
Function- position and movement sense
Stratum synovium
Rich vascularization
Poor innervation
Produce synovial fluid
Diarthrodial classification
Uniaxial
Biaxial
Triaxial
Uniaxial
Hinge joints
Pivot joints
Biaxial
Condyloid
Saddle
Triaxial
Plane joints
Ball and socket joints
Hyper mobile
Rom exceeds normal
Hypomobile
Rom less than normal
Contracture
No mobility
Osteokinematics
Rotary movement of the ones in space during physiological joint motion
Flex ext
In the sagittal plane
Around the x axis
Accessory motion
Motion of the joint surfaces in relation to another
Accompany voluntary osteokinematics motion but cannot be voluntary isolated
Terms used are roll, slide, spin
Convex-concave rule
Convex surface move on fixed concave surface then roll and glide occur in opposite directions
Concave surface move n fixed convex surface then roll and glide occur in same direction
Joint structure
To achieve normal motion the accessory motion has to be able to occur
Requires a certain amount of joint play
Loose packed position
Closed packed position (joint surfaces maximal congruent and the ligaments and capsule are taut)
Muscle tissue-contractile
Ability to develop tension in response to chemical, electrical or mechanical stimuli
Connective tissue-non contractile
Develops tension in response to passive loading
Muscle fiber
Single muscle cell enclosed in a cell membrane-the sarcolemma
Arrangement, size, type of muscle fibers in a muscle may vary from muscle to muscle
What are muscle fibers composed on
Sarcoplasm (cytoplasm)
Contains myofibrils, ribosomes, glycogen and mitochondria
Myofibrils are the contractile structure
Cross bridge interaction
Nerve impulse arrive at motor end plate
Evokes an electrical impulse-action potential
Release of calcium ions
Calcium ions cause troponin to reposition the tropomyosin molecules
Actin receptor site becomes free and the head of myosin can bind
Isometric contraction
No movement within fibers
Concentric contraction
Muscle fibers pull together
Eccentric contraction
Muscle fibers pull apart
DOMS
Injury due to eccentric exercise
Together with loss of coordination, swelling and muscle stiffness
Mechanical strain in the muscle fiber and associated CT
Normal action
Distal segment moves
Reverse action
Proximal segment moves and distal segment stationary
Motor unit
Alpha motor neuron
Muscle fibers it innervates
Muscle contraction is all of none principle at the motor unit level
Recruitment of motor units
Size principle of motor unit recruitment- initially small motor units, few muscle fibers
As force increases the larger motor units are recruited
Recruitment varies dependent of task and muscle
Factors affecting active muscle tension (5)
Number of muscle fibers Diameter of axon(conduction velocity) Number of motor units firing Frequency of motor unit firing Type of muscle fiber
What kind of fibers are dominant in stability or postural muscles
Type 1
What type of fibers are dominant in mobility or non postural muscles
Type 2
True or false- most muscle fibers have equal proportion of slow and fast fibers
True
Muscle fiber length
Number of sarcomeres along the fiber
Longer fibers can shorten by longer distances
Physiological cross sectional area
Amount of force is proportional to the number of sarcomeres aligned side by side (parallel)
Pennation angle
Arrangement of fascicles in relation to the long axis of the muscle
Length of muscle fiber and the distance to the muscle can move not directly related in a pennate muscle
Fusiform muscle
SCM
A lot of movement not alot of strength
Unipennate muscle
Flexor pollicis longus
More strength
Bipennate muscles
Biceps femoris
More strength
Tolerates hip flexion knee ext
Multipennate muscles
Soleus
1 joint, less mobility
All strength
Does all force production go towards producing motion at the lever??
No-some go on an angle
Helps with stability and venous return
Pennation angle and contraction
Changes with contraction
Pennate muscles have ________number of muscle fibers
Larger
Passive elastic component
The interconnected CT in a muscle
Parallel elastic component of a muscle
Tendon function in series with what?
Muscle
Muscle tension exerts force on:
Bony lever
Amount of force/ensign is combination of both:
Passive anD active tension
Passive tension
Tension developed in passive elastic component
Active tension
Tension developed by the contractile components
Active insufficiency
A muscle that cross more than one joint will have a decrease in the torque produced when all the joints are placed at end ROM so the muscle is in the shortened position
Triceps weaker extension
When muscle is shortest, you cannot get that much force
Passive insufficiency
When a multi joint muscle has been passively elongated to the point where it doesn’t allow full ROM at one or more of the joints it crosses
Isokinetic testing
Strength testing at a constant speed
Can produce maximal force throughout the whole ROM
Greater torque at slower speeds
Athletic activities are performed at higher speeds
Isotonic testing
Strength testing/ training at constant force
Muscles serve 2 basic functions
Provide mobility- produce or control joint motions
Provide stability- maintain joint integrity and postural alignment
Prime mover
Agonist
Muscle primarily responsible for causing the movement
Secondary movement
Synergist
Assists the prime mover
Important if prime mover is injured
Antagonist
Performs the opposite movement of the agonist
Contracts with the prime mover to cause co-contraction, a joint stabilization mechanism
Synergist
Helps agonist perform desired action
Produces force to prevent unwanted movement
Sometimes 2 prime movers can be synergist to one another
Golgi tendon organ
Located at the myotendinous junction
Sensitive to tension
Activated by active muscle contraction or passive tension
Adjust muscle tension
Muscle spindle
Specialized muscle fiber
Enclosed in connective sheath placed throughout muscle
Sensitive to the length and velocity of lengthening
When muscle contracts the spindle stops sending messages
Prolonged shortening
Decrease in number of sarcomeres
Increase in perimysium, thicker endomysium
Increase ratio of CT
Loss of weight and muscle atrophy
Prolonged lengthening
Increase sarcomeres
Increased muscle length
Fewer structural changes compared to shortened position
Immobilization 2 techniques
Prolonged shortening
Prolonged lengthening
Changes in muscle function
Increased activity level-hypertrophy, neural adaptation/ changes in early training
Decreased activity-atrophy
Aging- sarcopenia (loss of muscle mass), loss of muscle fibers and decrease in size of existing fibers
Stretch/shortening cycle/plyometric exercise
Muscle and tendon is stretched before a forceful concentric contraction
Helps produce a greater torque during the concentric contraction
Muscle power equation
Muscle work= force x distance
Muscle power= work/time
Muscle power
Power is the most accurate way to characterize muscle function
3 important components of muscle power
Magnitude of force
Distance of movement the muscle produces
How quickly the muscle produces movement
Muscle power predicts what
Mobility performance better than muscle strength
Leg movement velocity is as important to balance as what
Leg strength
Power can be increased in 3 ways
Increase the work done per unit of time
Decrease the time to perform a unit or work
Both of above simultaneously
Effect of stretching on performance
Stretch induced strength loss (neural effect)
Joint structure
To achieve normal motion the accessory motion has to be able to occur
Requires a certain amount of joint play
Loose packed position
Closed packed position (joint surfaces maximal congruent and the ligaments and capsule are taut)
