Final (Lectures 11-13; 30 Comprehensive Questions) Flashcards
1
Q
The mechanics of materials of human connective tissue
A
Tissue mechanics
2
Q
Components of tissue mechanics
A
Bones
Ligaments
Cartilage
Tendons
3
Q
An externally applied force
A
Load
4
Q
An objects response to load is determined by 7 things
A
- Magnitude
- Location
- Direction
- Duration
- Frequency
- Variability
- Rate
5
Q
A load that squeezes the parts of the body together
A
Compression
6
Q
A load that pulls the parts of a body apart
A
Tension
7
Q
A load applied perpendicular to the longitudinal axis of a body causing it to curve
A
Bending
8
Q
Three-point bending
A
Three forces applied which create two moments
9
Q
Four-point bending
A
Four forces applied
10
Q
The three factors determining the effect of bending on a body
A
- Cross-section area
- Distribution of the material around a neutral axis
- Length of the body
11
Q
A measure of a body’s resistance to bending
A
Area moment of inertia
12
Q
A combination of the cross-sectional area and the distribution of material around a neutral axis
A
Area moment of inertia
13
Q
A load that causes one part of a body to move parallel past another part
A
Shear loading
14
Q
Forces are directed towards each other; just not along the same line
A
Shear loading
15
Q
An example of shear loading
A
Cutting paper
16
Q
The type of loading that exists when there is a twist around the neutral axis
A
Torsion
17
Q
In this type of loading, a body is twisted around an axis
A
Torsion
18
Q
In this type of loading, the body is subjected to two or more types of loading
A
Torsion
19
Q
This type of loading depends on the distribution of the material
A
Torsion
20
Q
This tells you how the material that makes up the body will respond to loading
A
Material properties
21
Q
This tells you how the body as a whole responds to loading
A
Mechanical properties
22
Q
The 4 Components of mechanical properties
A
Strength
Deformation
Stiffness
Toughness
23
Q
The amount of loading an object can withstand before failure
A
Strength
24
Q
A change in dimensions of a body
A
Deformation
25
Determined as a change in length
Axial load
26
A characterization of an object that can undergo very small deformations
Brittle
27
A characterization of an object that can undergo very large deformations
Ductile
28
Example of a brittle object
Glass
29
Example of a ductile object
Gum
30
A deformation in which the object returns to its original dimensions
Elastic deformation
31
A deformation in which the object does not return to its original dimensions after deformation
Plastic deformation
32
Example of an elastic deformation
Rubber bands
33
Example of a plastic deformation
Plastic holding a six-pack of soda together
34
The amount of deformation that marks the transition from elastic to plastic deformations
Yield point
35
A deformation beyond this point results in permanent damage and microtearing
Yield point
36
The ratio of change in load to change in deformation
Change in load/change in deformation
Stiffness
37
The ratio of the change in deformation over the change in load
Change in deformation/change in load
Compliance
38
The amount of energy absorbed by the body as a result of deformation
Strain energy
39
The amount of energy that can be absorbed by a body before failure
Toughness
40
The way a force is distributed within a body
Stress
41
The change in dimension normalized to the original dimension
Strain
42
The ratio of stress to strain, or Young's Modulus
Elastic modulus
43
Relative amount of energy stored by the material
Strain energy density
44
A decrease in stress when the strain is held constant for a given period of time
Stress relaxation
45
An increase in strain when stress is held constant for a period of time
Creep
46
A fluid is both absorbed by the articulating surfaces and placed between them
Lubrication
47
The lubricating fluid prevents direct surface-to-surface contact
Boundary lubrication
48
Movement increases the amount of fluid between articulating surfaces, thus increasing their separation
Fluid film lubrication
49
3 types of fluid film lubrication
Squeeze film lubrication
Hydrodynamic lubrication
Elastohydrodynamic lubrication
50
Surface material is deformed and removed by frictional forces
Wear
51
Wear that occurs when two surfaces come in direct contact
Interfacial wear
52
Types of interfacial wear
Adhesion wear
| Abrasion wear
53
Wear that is the result of microdamage
Fatigue wear
54
A breaking apart of material
Material failure
55
Maximum stress exceeds the ultimate stress
Material failure
56
Strain exceeds the maximum strain
Material failure
57
When energy is entering more quickly than it is leaving,
It forms or propagates a crack in the material
58
Components of the model of injury
Failure tolerance
Actual stress
Margin of safety
59
The stress level above which failure will occur
Failure tolerance
60
How much stress the body is subjected to
Actual stress
61
The difference between the failure tolerance and the actual stress applied to a body
Margin of safety
62
An injury that happens immediately
Acute injury
63
An injury that develops over time
Chronic injury
64
A single external load creates enough stress that it exceeds the failure tolerance of the tissue
Acute injury
65
Outer layer of bone
Solid and dense
"Compact"
Cortical bone
66
Inner layer of bone
Less organized and random
"Spongy" "Cancellous"
Trabecular bone
67
The total amount of mineral in bone
Bone mineral content
68
The mineral content in an area or volume of bone
Bone mineral density
69
The overall strength of bone is not only determined by an increase in bone density, but also by where that bone is placed
Wolfe's Law
70
Exhibits different properties when measured in different directions
Allows for stiffness and brittleness
Anisotropic
71
The breaking of a bone
Fracture
72
Lower than normal bone mineral density
Osteopenia
73
Severe decrease in bone mineral density
Osteoporosis
74
Bone health has an inverse relationship with
Age and disuse
75
Bone health has a direct relationship with
Weight bearing exercise
76
3 types of cartilage
Articulate (hyaline) cartilage
Fibrocartilage
Elastic cartilage
77
Covers the articular surface of bones
Articular (hyaline) cartilage
78
Has a specialized role
Fibrocartilage
79
Found in external ear, parts of the nose, and other places
Elastic cartilage
80
Function of articular cartilage
Distributes load transmitted across the joint, which decreases the stress on joint surfaces.
Allows for relative movement of two opposing joints surfaces with minimal wear and tear by decreasing friction.
81
Mechanics of articular cartilage
Primarily loaded under compression
Lubricates the joints
Is permeable
82
2 components of articular cartilage that allow it to be loaded under compression
Solid
| Liquid
83
The progressive degeneration of the articular cartilage and the bone deep to it
Osteoarthritis
84
Cartilage decreases in thickness and becomes more rough
Osteoarthritis
85
Cause of osteoarthritis
Unknown
86
Risk factors of osteoarthritis (5)
1. Aging
2. Weakness
3. Obesity
4. Malalignment
5. Injury
87
Function and structure of ligaments
Connect bone to bone
Restrict certain movements
Guide certain movements
88
Generally resist tensile loads in one direction, but offer little resistance to compressive loads
Ligaments
89
An injury to a ligament that occurs when it is stretched beyond its capacity
Usually occurs when a ligament is forcibly wrapped around a part of a bone
Sprain
90
Less is known about the mechanics of these tissues in comparison to other tissues
Ligaments
91
Muscles can only control movement by transmitting force through
Passive components (tendons) to the skeletal segments
92
The only action muscles can perform
Muscles can only pull
93
How does force work in the muscle-tendon complex?
Force works to bring two insertion points closer together.
94
Muscles can act as
A motor, brake, spring, or strut
95
An action in which the muscle-tendon complex develops greater torque than the external torque acting on it and shortens.
Concentric action
96
Torque and displacement are in the same direction; MTC is doing positive work and increasing the energy of the skeletal system
Concentric action
97
An action in which the MTC develops less torque than the external torque acting on it and lengthens
Eccentric action
98
Torque and displacement are in the opposite direction; MTC is doing negative work and decreasing the energy of the skeletal system
Eccentric action
99
A concentric action immediately after an eccentric action
Stretch-shortening cycle
100
Energy stored during the eccentric action contributed to the movement during the concentric action
Stretch-shortening cycle
101
An action in which the MTC develops less torque than the external torque acting on it and lengthens
Eccentric action
102
Torque and displacement are in the opposite direction; MTC is doing negative work and decreasing the energy of the skeletal system
Eccentric action
103
A concentric action immediately after an eccentric action
Stretch-shortening cycle
104
Energy stored during the eccentric action contributed to the movement during the concentric action
Stretch-shortening cycle
105
An action in which the MTC develops a torque that is equal to the external torque acting on it and does not change length
Isometric action
106
There is no displacement; the MTC is doing no work; the energy of the skeletal system remains unchanged
Isometric action
107
Determines both the force producing capabilities and operating range of a muscle
Muscle architecture
108
Refers to his fibers are arranged relative to the vector of force generalization
Can be parallel or penate
Muscle architecture
109
One of the passive elements in the MTC
Tendons
110
Are not straight; have a natural crimp or waviness
Type 1 Collagen
111
Arrange more like sheets
| Converge at ends of the muscle bellies to form tendons
Fascia
112
Have both elastic and viscous properties
Viscoelastic
113
The primary components of tendon structure
Type 1 collagen
| Fascia
114
Structural property of tendons
Viscoelastic
115
Tendons act similar to
Rubber bands
116
A resistance to change in deformation
Stiffness
117
The opposite of stiffness
Compliance
118
Stiffer materials require more ____ to achieve the same amount if deformation
Force
119
The total force produced in a tendon
Sum of the viscous and elastic properties
120
Energy is being stored when the tendon is
Lengthening
121
Energy is being released when the tendon is
Shortening
122
Equals the anatomical cross-sectional area for a parallel muscle arrangement
Physiological cross-sectional area
123
An increase in the number of muscle fibers
Hyperplasia
124
An increase in the size of muscle fibers
Hypertrophy
125
The action of the MTC determines
the amount of force it produces
126
___ produces more force than ___.
Eccentric, concentric
127
Why does eccentric action produce more force?
Muscle fibers are attempting to act isometrically as the tendons lengthen.
128
The amount of force that can be produced per cross-sectional area
Specific tension
129
A motor neuron and all the fibers it innervates
Motor unit
130
Muscle recruitment is governed by two principles
All or none principle
| Size principle
131
An action potential does not directly excite muscle fibers, but does so through chemical processes.
If the action potential is strong enough, all the fibers innervated by that nerve will contract.
All or none principle
132
The all or none principle is similar to
firing a gun
133
Motor units are recruited in an orderly process from the smallest to largest.
Size principle
134
Which type of muscle is recruited first?
Type I
135
Type II muscle fibers are recruited as
more force is needed.
136
Force output is changed by either
Increasing the firing frequency, or
| Activating more motor units
137
The time between onset of electrical activity at the muscle and production of measurable force
Electrochemical delay
138
Why does the electrochemical delay happen?
It provides:
Time needed for chemical processes
Time needed for cross-bridge formation, and
Time needed to take up the slack in the tendon.
139
Many activities occur in ___ time than it takes to develop the ___ amount of force.
less, maximum
140
The stretch shortening cycle
A well timed pre-activation of the muscle prior to the eccentric action
A short rapid eccentric action
An immediate transition from the eccentric action to the concentric action
141
Any reduction in force-generating capacity of the total neuromuscular system, regardless of the force required in any given situation.
Fatigue
142
The inability to continue or complete a desired action
Task failure
143
Occurs because one or several of the physiological processes involved in force production of the contractile proteins become impaired
Fatigue
144
Can occur in many potential sites within the neuromuscular system
Fatigue
145
The force-producing capabilities of the MTC decrease with
aging and disuse
146
A decrease in the physiological cross-sectional area
Atrophy
147
Age-related decrease in muscle mass
Sarcopenia
148
How is the tendon affected by aging and disuse?
Rapid decrease in stiffness and elastic modulus
| Decrease in cross-sectional area
149
How does heavy resistance training alter all the factors in the MTC?
Increases physiological cross-sectional area
Increases number of sarcomeres in a series
Increases force production (by improving recruitment and changing specific tension)
150
Injury to a muscle
Strain
151
Injury to a ligament
Sprain
152
The mechanics that result in an injury
Mechanopathology
153
The mechanics that are a result of an injury
Pathomechanics
154
It is accepted that strains are a result of
both a stretch and load placed on the muscle.
155
Strains occur during
eccentric muscle actions due to both excessive stress and mechanical strain.
156
The mechanopathology of this tissue is very poorly understood.
Tendon mechanopathology
157
Which undergoes greater strain: muscles or tendons?
Tendons
158
Repetitive straining can lead to
degenerative changes, which can lead to rupture
159
Has the ability to regenerate
Muscle
160
When muscle regenerates, it is sometimes replaced with scar tissue. What does scar tissue do in muscle?
It decreases optimal length, decreases range of motion, and leads to high incidence of reinjury.
161
Alters both mechanical and material properties
Tendon
162
How does tendon alter mechanical and material properties?
Tendon increases cross-sectional area by decreasing stiffness and Young's Modulus.
163
Occurs in a plane about an axis that is perpendicular to that plane.
Rotations
164
The plane of movement will not be coincident with any of the cardinal planes if
the axis is oblique.
165
Reference frames are attached locally to bone so that
problems with a global reference frame are avoided.
166
Rotations of bones
Osteokinematic Motion
167
Motions at the joint
Arthrokinematic Motion
168
The amount of rotation, measured in degrees available at a joint.
Range of motion
169
An angle between the long axis of the bone and some reference line
Segment angle
170
The angle between the long axis of the bone and some reference line in the global reference frame
Absolute
171
The orientation of one bone is measured relative to the orientation of another bone
Relative
172
The number of movements available
Degrees of freedom
173
1 degree of freedom
A movement in two directions (i.e.: flexion and extension)
174
Gliding joints
0 rotational degrees of freedom
| No axis of rotation
175
Hinge joints
1 rotation degree of freedom
| 1 axis of rotation
176
Pivot joints
1 rotational degree of freedom
| 1 axis of rotation
177
Condyloid joints
2 degrees of freedom
| 2 axis of rotation
178
Saddle joints
2 degrees of freedom
| 2 axis of rotation
179
Spherical (ball and socket) joints
3 degrees of freedom
| 0 Axis of rotation
180
Examples of hinge joints
Ankle
Elbow
Interphalangeal joints
181
Examples of pivot joints
Proximal radioulnar joint
182
Examples of condyloid joints
Wrist (radialcarpal joint)
183
Examples of saddle joints
First carpometacarpal joint
184
Examples of spherical (ball and socket) joints
Hip (glenohumeral joint)
185
What is the purpose of manual therapy?
Breaks up adhesions and scar tissue to improve movement and range of motion at the joint.
186
3 types of arthrokinematic motion
1. Gliding (sliding) - pure translation
2. Spinning - pure rotation
3. Rolling - combo of gliding and spinning
187
3 effects of the force produced by the MTC
1. Compression or distraction of the joint
2. Shear across the joint
3. Rotation of the joint
188
This component causes rotation or shear
Perpendicular component
189
This component causes compression and distraction
Parallel component
190
This determines the amount of torque produced by an MTC
1. The amount of force produced
| 2. Moment arm
191
The MTC moment arm is determined by
1. The length from the axis of rotation to the insertion point.
2. The direction of the line of pull.
192
2 factors that determine the direction of the line of pull
1. The sense
| 2. The angle of pull from the long axis of the bone
193
The sense
Direction of pull
194
Which part of the moment arm has a more profound effect: the length or the angle?
The length
195
Newton's First Law
A body will remain at rest or continue to move with a constant speed in a straight line unless acted upon by an outside force.
196
Newton's Second Law
Acceleration is caused by a net force and is proportional to the magnitude of the force, and in the direction of the force.
197
Newton's Third Law
For every force, there is an equal and opposite reaction force.
198
Formula for Newton's Second Law
Force = (mass)(acceleration)
199
Formula for Impulse
Impulse = (force)(time)
200
Impulse is basically the same as
Momentum
201
The product of average force and the time that force is applied.
Equal to the change in momentum
Impulse
202
A resistance to change in motion, specifically resistance to change in a body's velocity.
Inertia
203
A resistance to change in velocity of a moving body
Momentum
204
Formula for Momentum
Momentum = (mass)(linear velocity)
205
The amount of matter in an object
Mass
206
The angular equivalent of mass
Moment of inertia
207
Gives an indication of how difficult it will be to rotate an object
Moment of inertia
208
Formula for moment of inertia
Moment of inertia = (mass)(distance from the COM to the axis of rotation)^2
I=MK^2
209
Formula for angular momentum
Angular momentum = MK^2 x angular velocity
210
A push or pull by one body on another
Force
211
The turning effect of a force
Torque
212
Moment of force
Torque
213
Formula for torque
Torque = (lever arm)(perpendicular force)
214
Formula for work
Work = (force)(distance)
215
4 functions of a lever
1. Balance 2 or more forces
2. Change direction of the applied force
3. Favor speed and range of motion
4. Favor force production
216
A rigid body that is used in conjunction with a pivot point to multiply the force or speed applied to another body
Lever
217
5 components of a lever
1. Applied force
2. Force moment arm
3. Axis of rotation
4. Resistance force
5. Resistance moment arm
218
Levers are classified by
the force, the axis, and the resistance.
219
First class lever
F-A-R
220
First class lever favors
All four functions of a machine
221
Example of first class lever
Neck extension
| Elbow extension
222
Second class lever
A-R-F
223
Second class lever favors
force production
224
Examples of second class levers
Push ups
| Toe raise
225
Third class lever
A-F-R
226
Third class levers favor
resistance and speed and ROM
227
Examples of third class levers
Elbow flexion
228
The state of matter that makes things change, or has the potential to make things change
Energy
229
The 5 types of energy
1. Nuclear
2. Chemical
3. Electromagnetic
4. Acoustic
5. Mechanical
230
Energy due to motion
Kinetic energy
231
Energy due to position or deformation
Potential energy
232
Energy due to deformation
Strain potential energy
233
Potential energy due to position
Gravitational potential energy
234
The process of changing the amount of energy in a system.
| Can only occur if there is displacement
Work
235
The time rate of doing work.
| How quickly energy is entering or leaving a system.
Power
236
Formula for power
Power = work/change in time
237
How far a body has traveled
Distance
238
A change in position
Displacement
239
How fast a body is moving in a particular direction
Velocity
240
The time rate of change in position
Velocity
241
Change in velocity/change in time
Acceleration
242
Formula for kinetic energy
KE = 1/2(m)(v^2)
