Exam 1 Flashcards
(249 cards)
1
Q
Define Kinesiology
A
The study of movement
2
Q
What fields are used in kinesiology?
A
Anatomy
Physics
Geometry
…all used and related to human movement
3
Q
What principles are utilized in kinesiology?
A
Mechanics or Biomechanics
Musculoskeletal Anatomy
Neuromuscular Physiology
4
Q
Define “Static”
A
nonmoving interaction of an object
5
Q
Define Dynamic Movement
A
Moving interaction of an objects
6
Q
Define Kinetics
A
Those forces causing movement.
Ex: pushing, pulling, collision
7
Q
Define Kinematics
A
The time, space and mass aspects of a moving system
Ex: speed, friction, resistance or weight of an object
8
Q
List examples of Static movement
A
Laying supine or prone
Sitting on the edge of the bed
Stil Stance
Watching TV on the couch
9
Q
What are some examples of Dynamic Movement?
A
Rolling in bed
Transitioning from supine to sit
Putting on your sock
Walking down the hallway
10
Q
Why is movement important?
A
Helps clinicians recognize balance and strength issues of patients
11
Q
What is Anatomical Position?
A
Upright position Eyes facing forward Feet parallel & close together Arms at the side of the body Palms of hands facing forward
12
Q
What is Fundamental Position?
A
Same as anatomical position, except palms are facing toward the body
13
Q
What is Fundamental Position used form?
A
To describe the ROTATION of the upper extremity
14
Q
What is Linear Motion?
A
Straight line from one location to another
15
Q
What are 2 types of Linear Motion?
A
Rectilinear Motion & Curvilinear Motion
16
Q
What is Rectilinear Motion?
A
Linear motion in which all parts of the object move in the same direction in a same line.
Ex: Child sledding/skateboarding
17
Q
What is Curvilinear Motion?
A
A type of Linear Motion in which movement occurs linearly but in a curved path but not a circular path.
Ex: Diver off a board curving down into the pool
(MOST HUMAN MOVEMENT IS CURVILINEAR)
18
Q
What is Angular Motion?
A
All parts of the object move through the same angle, same direction at the same time.
They DO NOT move the same distance.
Ex: Arm: wrist, forearm and elbow into flexion - all parts move at the same speed but forearm travels further
19
Q
What is another name for Angular Motion?
A
Rotary Motion
20
Q
What is another name for Linear Motion?
A
Translatory Motion
21
Q
What is Osteokinematics?
A
Joint Movement by muscular initiation
22
Q
What is Flexion?
A
Bending movement of one bone on another causing a DECREASE in the joint angle.
23
Q
Where does flexion usually occur?
A
Between the anterior surface of bones
24
Q
What is the term for flexion of the wrist?
A
Palmarflexion
25
What is flexion in the ankle called?
Dorsiflexion
26
What is Extension?
Straightening movement of one bone on another, causing an INCREASE in the joint angle.
27
What is the term for extension of the angle?
Plantar Flexion
28
Define Hyperextension
Greater than normal ROM
29
What is Horizontal Abduction?
Joint (shoulder) flexed to 90 degrees and moved away from the body
30
What is another name for Medial Rotation?
Internal Rotation
31
What is another name for Lateral Rotation?
External Rotation
32
What is Radial Deviation?
Hand moves laterally or toward the THUMB side in anatomical position.
33
What is Ulnar Deviation?
Hand moves medially from the anatomical position toward the LITTLE FINGER
34
What is Protraction?
Movement AT THE SHOULDER: flexion to 90 degrees and UE is parallel to the ground pushing forward/away from the midline.
35
What is Retraction?
Movement at the SHOULDER: Flexion to 90 degrees and UD is pulling towards the midline of squeezing the shoulder blades together.
36
What is Circumduction?
Movement that involves 4 major motions:
1. Flexion
2. Abduction
3. Extension
4. Adduction
37
How many bones are in the Appendicular Skeleton?
126
38
How many total bones are in the human body?
206 - can be more due to sesamoid bones
39
Where does longitudinal bone growth occur?
In the epiphysis
40
Where is the endosteum located?
It is the membrane lining the medullary canal (in the diaphysis)
41
What is the Metaphysis?
The portion of a long bone that supports the epiphysis - the flared portion of the bone
42
Where is the periosteum located?
Membrane covering bones - except on articular surfaces
43
The Periosteum contains blood vessels. True or False?
True
44
What membrane of the bone promotes growth in diameter of immature bone? This membrane also repairs damaged bone.
The Periosteum
45
What is the definition of long bones?
Length is greater than the width of the bone
46
What is the definition of short bones?
The bones are more or less equal in height, length & width.
47
What is the definition of Flat Bones?
Flat bones have broad surfaces but are not very thick. They tend to have a curved surface rather than a flat one.
48
What are Irregular Bones?
These bones have mixed shapes of bones that don't fit into any other category.
49
What are Sesamoid Bones?
They resemble seeds and are located in tendons. They are free floating bones.
50
What are the 3 basic types of joints?
1. Fibrous
2. Cartilaginous
3. Synovial
51
What are the 3 types of Fibrous Joints?
1. Synarthrosis
2. Syndesmosis
3. Gomphosis
52
What are Synarthroses?
Suture joints
Ex: Skull
53
What are Syndesmoses?
Ligamentous joints that have a great deal of fibrous tissue (such as ligaments & interosseous membranes) which hold the joint together.
Ex: Distal Tibiofibular Joint
Distal Radioulnar Joint
54
What are Gomphoses?
Joints that "bolt together"
Ex: Tooth and socket of the mandible or maxilla
55
What is another name for Cartilaginous Joints?
Amphiarthrodial Joints
56
What are Cartilaginous Joints?
They have either hyaline or Fibrocartilage between 2 bones. They allow a small amount of motion (bending/twisting/some compression). Not as stable as Fibrous Joints but allow more movement.
Ex: Pubic Symphysis & Vertebral Disks
57
What are Synovial Joints?
There is a cavity at the end of one bone, rather than direct contact union between bone ends.
- Synovial fluid in thick, sleeve-like capsule
* Strong outer surface of fibrous material - holds jt together
* Inside lined with synovial membrane that secrets synovial fluid
* Provides shock absorption & nutrition to cartilage
58
What is another name for synovial joints?
Diarthrodial Joints
59
Describe the articular surfaces of synovial joints.
They are very sooth and covered with hyaline (articular) cartilage which allows easy/functional movement
60
What type of joints comprise the majority of the joints in the body?
Synovial Joints
61
What is a Nonaxial Joint?
It allows linear movement, not angular. These joint movements occur secondary to other motions. They have 0 DOF.
Ex: Carpal bones (intercarpal joints)
62
What type of movement occurs in Nonaxial Joints?
Gliding
63
What shape are Nonaxial Joints?
Irregular (plane)
64
What are Uniaxial Joints?
Angular motion occurs in ONE PLANE around ONE AXIS.
65
What are the 2 types of Uniaxial Joints?
Hinge Joints & Pivot Joints
66
What type of movement occurs in a hinge joint?
Flexion / Extension
67
List 3 examples of hinge joints.
Elbow
Interphalangeal Joints
Knee (except for the last few degrees of extension as it rotates)
68
What type of movement occurs in a pivot joint?
Rotation
Ex: Radius/Ulna; Atlas/Axis
69
What are Biaxial Joints?
Movement occurs in 2 different directions
70
What are the 2 types of Biaxial Joints?
Condyloid (ellipsoidal) & Saddle Joints
71
What kind of movement occurs in Condyloid Joints?
Flexion / Extension
and
Abduction / Adduction
Ex: Wrist & Metaphalangeal joints
72
What type of movement occurs in Saddle Joints?
Flexion / Extension
and
Abduction / Adduction
(also rotation as an accessory movement)
73
What is the one location in the body with a Saddle Joint?
The Thumb - the 1st Carpometacarpal Joint
74
What is the difference between Condyloid & Saddle Joints?
Arthrokinematics
| will be explained later
75
What are Triaxial Joints?
Motion occurs actively in ALL 3 AXES.
76
What type of joint is a ball & socket?
Triaxial
77
What movements occur in a Triaxial Joint?
Flexion / Extension
Abduction / Adduction
Rotation
78
What are the functions of ligaments in a joint?
Hold bones & capsule together
Provide attachments for cartilage, fascia or muscle
Allow for flexibility but prevent excessive movement
79
What are ligaments?
Bands of fibrous connective tissue.
80
What type of cartilage covers the ends of opposing bones?
Hyaline Cartilage (a/k/a articular cartilage)
81
What type of cartilage acts as a shock absorber?
| Ex: miniscus (knee), intervertebral disks, labrum in the hip/shoulder joints
Fibrocartilage
82
Where can elastic cartilage be found?
- External ear
- Nose (tip)
- Eustachian Tube
- Epiglottis
- Opening of the respiratory tract
83
What is the most common type of cartilage found in the body?
Hyaline Cartilage
84
What is the strongest, most durable type of cartilage in the body? What makes is so strong?
Fibrocartilage - due to the large number of cartilagenous fibers
85
What type of cartilage is most resilient?
Elastic Cartilage
86
What is the function of tendons?
Connect muscles to bones
87
What is an aponeurosis?
A broad, flat tendinous sheath of tendon that provides great strength.
Ex: Abdominals / Latissimus Dorsi / Cranium
88
What are Tendon Sheaths?
They cover tendons and prevent excess friction, especially when the tendon passes through a tunnel.
89
What are Bursae?
Small, pad-like sacs that help reduce friction between moving parts in the joints.
They can be natural or acquired due to excessive friction.
90
What is an avulsion?
A bone fracture wherein a piece of bone is pulled away, attached to tendon or ligament. May affect muscle.
91
What is a dislocation?
Complete separation of 2 articular surfaces of a joint. It is likely that a portion of the joint capsule will be torn.
92
What is subluxation?
A partial dislocation of a joint that usually occurs over a period of time.
- Commonly from weakened ligaments, overuse or medical etiology
- CVA patients can have this happen due to weight of a bone in a paralyzed area (why you often see them wearing a sling - prevent damage to the shoulder)
93
What is Tenosynovitis?
Inflammation of a tendon sheath
94
What type of movement occurs in the Saggital Plane?
| What AXIS do these motions pivot around?
Flexion / Extension - pivot around the X Axis
95
What 2 special cases occur in the Saggital Plane?
Wrist: Sagittal Plane runs through the 3rd Digit
Foot: Sagittal Plane runs through the 2nd Digit
96
What motion occurs in the Frontal Plane?
| What AXIS does this movement pivot around?
Abduction / Adduction - pivots around the Z axis
97
What type of motion occurs in the Transverse Plane?
| What AXIS does this motion pivot around?
Rotation: Medial & Lateral; Pronation / Supination
- pivots around the Y axis
98
What is the term for the point of intersection of the 3 Cardinal Planes?
Center of Gravity
99
Where is the center of gravity located in an adult?
Midline, just anterior to S2
100
What are kinetic chains?
A combination of several joints or links connected in a way to allow movement. Movement of on link causes motion at other links in a predictable way.
101
Do more distal segments in a kinetic chain have higher or lower degrees of freedom than proximal segments?
HIGHER
102
How many degrees of freedom exist between the thoracic wall to the finger? (That can be identified)
19 DOF
103
How many degrees of freedom occur between the pelvis and the toe?
25 DOF
104
Degrees of freedom in the LE permit feet to adjust to irregular or slanting surfaces. How do they affect the body's center of gravity?
The degrees of freedom allow the COG to be maintained within the small base of support of the planted foot.
105
Is the shoulder joint:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
d) Triaxial
106
What is the anatomical description of the shoulder joint?
ball & socket
107
What motions occur at the shoulder joint?
Flexion / Extension
ADD/ABD
Rotation
108
How many degrees of freedom does the shoulder have?
3 DOF
109
Is the elbow:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
b) Uniaxial
110
What is the anatomical description the elbow joint?
Hinge
111
What motions occur at the elbow?
Flexion / Extension
112
How many degrees of freedom does the elbow have?
1 DOF
113
Is the knee:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
b) Uniaxial
114
What is the anatomical description of the knee joint?
Hinge
115
What motions occur at the knee?
Flexion / Extension
116
How many degrees of freedom does the knee have?
1 DOF
117
Are intercarpal joints:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
a) Non-Axial
118
What is the anatomical description intercarpal joints?
Irregular
119
What motions occur at the intercarpal joints?
Gliding
120
How many degrees of freedom do intercarpal joints have?
0 DOF
121
Is the Atlas/Axis joint:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
b) Uniaxial
122
What is the anatomical description of the Atlas/Axis joint?
Pivot Joint
123
What motions occur at the Atlas/Axis joint?
Rotation (Right & Left)
124
How many degrees of freedom does the Atlas/Axis joint have?
1 DOF
125
Is the Proximal Radioulnar joint:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
b) Uniaxial
126
What is the anatomical description of the Proximal Radioulnar joint?
Pivot Joint
127
What motions occur at the Proximal Radioulnar Joint?
Rotation
128
How many degrees of freedom does the Proximal Radioulnar Joint have?
1 DOF
129
Is the Radiocarpal Joint (wrist):
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
c) Biaxial
130
What is the anatomical description of the Radiocarpal Joint (wrist)?
Condyloid
131
What motions occur at the Radiocarpal Joint?
Flexion / Extension
| ADD / ABD
132
How many degrees of freedom does the Radiocarpal Joint have?
2 DOF
133
Is the CMC #1 (thumb):
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
c) Biaxial
134
What is the anatomical description of the CMC #1 (thumb) joint?
Saddle
135
What motions occur at the CMC #1 (thumb) joint?
Flexion / Extension
ADD / ABD
(accessory to rotation - only by adding other motions)
136
How many degrees of freedom does the CMC #1 (thumb) joint have?
2 DOF
137
Is the hip:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
d) Triaxial
138
What is the anatomical description of the hip?
ball & socket
139
What motions occur at the hip?
Flexion / Extension
ADD / ABD
Rotation
140
How many degrees of freedom does the hip have?
3 DOF
141
Are the ribs:
a) non-axial
b) uniaxial
c) biaxial
d) triaxial
a) Non-Axial
142
What is the anatomical description of the rib joints?
Irregular
143
What motions occur at the rib joints?
Rib #1 is immoveable (synchondrosis)
| Ribs 2-7 are partial synovial joints - gliding
144
How many degrees of freedom do ribs have?
0 DOF
145
What motions take place in the Frontal Plane?
ABD / ADD
146
What Axis is located in the Frontal Plane?
Z Axis
147
What motions take place in the Sagittal Plane?
Flexion / Extension
148
What Axis is located in the Sagittal Plane?
X Axis (a/k/a horizontal axis)
149
What motions take place in the Transverse Plane?
Rotation
150
What Axis is located in the Transverse Plane?
Y Axis (a/k/a vertical axis)
151
Where is the center of gravity located in the adult?
Midline & slightly anterior to S2
152
What the definition of Synarthrosis?
This is a type of fibrous joint a/k/a suture joints.
| Their shape allows bones to interlock & fit tightly together.
153
What is an example of a synarthrosis?
Skull
154
What is the definition of Syndesmosis?
This is a type of fibrous joint that is ligamentous.
| These joints have a great deal of fibrous tissue (ligaments/interosseous membranes) holding the joint together.
155
Examples of Syndesmoses:
Distal Radioulnar Joint
| Distal Tibiofibular Joint
156
What is the definition of Gomphosis?
This is a type of fibrous joint which "bolts together" its parts.
157
What is an example of a Gomphosis?
Tooth & Socket (mandible/maxilla)
158
What is the definition of an Amphiarthroidial Joint?
This is another name for Cartilaginous Joints.
These joints have either hyaline cartilage or fibrocartilage between two bones. (like disks)
They allow a small amt of motion (bending/twisting and some compression)
159
Examples of Amphiarthroidial joints:
Pubic Symphysis
| Vertebral Disks
160
What is the definition of a Synovial Joint?
These Joints have no direct contact union between the ends of the bones. They have a cavity instead.
A/K/A Diarthrodial Joints
Cavity is filled with synovial fluid located within a thick, sleeve-like capsule
161
Examples of Synovial Joints:
Hip
Elbow
Knee
162
Describe the structure of a synovial joint capsule:
| 3 Important details
1. Outside is a strong, fibrous material that holds the joint together
2. The inside is lined with a synovial membrane that secretes synovial fluid
3. Provides shock absorption and is a major source of nutrition for cartilage
163
What are the 3 types of cartilage?
1. Fibrocartilage
2. Hyaline Cartilage
3. Elastic Cartilage
164
What type of cartilage is the most durable? What makes it so durable?
Fibrocartilage - due to the large amount of cartilaginous fibers
165
What type of cartilage is typically found on articular surfaces of synovial joints?
Hyaline
166
What is the most common type of cartilage in the human body?
Hyaline
167
Where is elastic cartilage found?
External Ear
Eustachian Tube
Epiglottis
Opening of the Respirator Tract
168
What is the purpose of studying clinical kinesiology?
To understand the forces acting on the human body causing movement (biomechanics) and to manipulate these forces in treatment procedures so that human performance may be improved and further injury may be prevented.
169
What is Mechanics?
It is concerned with the effects of forces acting on objects
170
What is Biomechanics?
The study of how forces lead to movement in the human body
171
What are the 4 main forces on the human body?
1. Gravity
2. Muscle Tension
3. External Resistance
4. Friction
172
How does gravity affect movement?
weight of body parts and attachments like splints, casts, eating utensils, books or weights
173
How does muscle tension affect movement?
Muscles produce forces on the bone segments by active contraction or by being passively stretched
174
How does friction affect movement?
It can provide stability if optimum, retard motion if excessive and lead to instability if inadequate.
175
What does the term Statics mean?
It deals with NON-movement systems
176
What does the term Dynamics mean?
Deals with moving systems
177
What are the two parts of Dynamics?
Kinetics & Kinematics
178
What is Kinetics?
It is a description of motion with regard to what causes motion.
179
What is Kinematics?
The science of motion of bodies in space, osteokinematics & arthrokinematics
180
What is Osteokinematics?
How the bones move in space without regard to the movement of joint surfaces
181
What is arthrokinematics?
How adjoining joint surfaces move in relation to eachother
182
What is a vector?
A quantity having both magnitude and direction
183
What is Force?
A push or pull action that can be represented as a vector
184
What is Scalar?
It describes magnitude only
| Length, Area, Speed, Volume & Mass
185
What is Mass?
It refers to the amount of matter that a body contains
186
What is Inertia?
The property of matter that causes it to resist any change of its motion in either speed or direction
187
What is Torque?
The tendency of force to produce rotation about an axis
188
What is Friction?
A force developed by two surfaces (prevents motion of one surface across another)
189
What is Velocity?
A vector that describes speed and is measured in units: feet per second / miles per hour
190
What is Newton's 1st Law?
The Law of Inertia:
| An object at rest tends to stay at rest - an object in motion tends to stay in motion
191
What is Newton's 2nd Law?
The Law of Acceleration:
| The amount of acceleration depends on the strength of the force applied to the object
192
What is Acceleration?
Any change in the velocity of an object
193
What is always needed to change the direction an object is moving?
Force
194
How does Mass affect acceleration?
Acceleration is inversely proportional to the mass of an object
195
What is Newton's 3rd Law?
The Law of Action-Reaction:
| For every action, there is an equal and opposite reaction
196
What kind of motion can occur without a force?
NONE! No motion can occur without force
197
What kind of internal forces cause motion?
muscular contraction
ligamentous restraint
tendon restraint
bony support
198
What kind of external forces cause motion?
gravity
weight
friction
etc.
199
What kind of force is created by Push?
Compression
200
What kind of force id created by Pull?
Tension
201
When does movement occur in a Push/Pull situation?
When one side of force is greater than the other.
202
When a person is pulling a load with a rope, what is the magnitude of the vector?
The rope tension
203
When a person is pulling a load with a rope, what is the direction of the vector?
The direction of the rope
204
When two people are pulling on opposite sides of a rope (tug of war), what happens when the tension is equal on both side?
There is no movement
205
When two people are pulling on opposite sides of a rope (tug of war), what is the Point of Application?
The center from which both forces are originating
206
What is Linear Force?
It results when 2 or more forces are acting along the same line
207
What is Parallel Force?
It occurs in the same plane and in the same or opposite direction
208
What is Concurrent Force?
2 or more forces must act from a common point but pull in different directions. (The example of 2 people pushing a desk from 2 sides)
209
In a Concurrent Force, what is the net effect of the 2 forces called?
Resultant Force
210
What are Force Couples?
2 forces act in an equal but countercurrent or opposite direction resulting in a turning effect.
Ex: Jar lid
Spinning in an innertube
Trapezius turns the Scapula
211
The amount of torque on a lever depends on what 2 things?
1. The amount of force that is applied
2. The distance it is from the axis
Remember the wrench example
212
In the body, what is Torque?
The amount of force needed by a muscle contraction to cause rotary joint action.
213
In the body, what is the moment arm? (torque arm)
The perpendicular distance between the muscles line of pull and the center of the joint (the axis of rotation)
214
When is torque the greatest?
When the angle of pull is at 90 degrees
215
If the angle of pull DECREASES from the perpendicular position, what happens to Torque?
Torque decreases
216
If the angle of pull INCREASES from the perpendicular position, what happens to Torque?
Torque decreases
217
In the body, what is Stabilizing Force?
When nearly all of the force generated by the muscle I directed back into the joint, pulling the bones together.
218
Where does Stabilizing Force occur in the body?
In joints when they are close to 0 degrees.
Ex: Elbow going into ext - distance of the moment arm is less and nearly all of the force generated by the muscle is directed back into the joint and pulls the two bones together
219
What are 2 uses of Sesamoid Bones?
Protect tendons
and
Mechanical Advantage
220
What are the 3 types of force related to Torque?
1. Stablizing Force
2. Angular Force
3. Dislocating Force
221
What is a Dislocating Force?
When the angle of pull is past 90 degrees, the force is directed away from the joint.
222
What is Angular Force?
When the angle of pull is at 90 degrees, the perpendicular distance between the joint axis and line of pull is much larger, causing an angular or movement force.
(most of the force generated by the mm is directed at moving the joint and not stablilizing the joint)
223
What is the term used when an object is balanced and all torques acting on the object are even?
State of Equilibrium
224
In a State of Equilibrium, stability is reliant upon what?
The relationship between the object's center of gravity and base of support.
225
What is Gravity?
The mutual attraction between the earth and an object
226
Where is gravitational force directed?
Vertically downward toward the center of the earth
227
What is Center of Gravity?
The balance point of an object at which torque on all sides is equal.
228
Is a child's COG higher or lower than an adult?
Higher
229
What is Base of Support?
The area of the body that is in contact with the supporting surface
230
What is Line of Gravity?
An imaginary vertical line passing through the COG toward the center of the earth.
231
What is Degree of Stability?
Resistance to being overthrown
232
What 4 factors affect degree of stability?
1. The height of the center of gravity above the base of support
2. The size of the base of support
3. The location of the gravity line within the base of support
4. The weight of the body
233
What 4 things enhance stability?
1. Low COG
2. Wide BOS
3. Gravity line at center of support
4. Heavy Weight
234
What 3 things enhance Instability?
1. High COG
2. Narrow BOS
3. Light weight
235
When does Stable Equilibrium occur?
When an object is in a position that to disturb it would require its COG to be raised
Ex: Person laying on the floor - you would have to tip them up to change their equilibrium
236
When does Unstable Equilibrium occur?
When only a slight force is needed to disturbe the object.
Ex: Balancing a domino upright or a person standing on one leg
237
When does Neutral Equilibrium occur?
When an object's COG is neither raised nor lowered when it is disburbed.
238
What are the 8 rules of stability?
1. The lower the COG, the more stable the object
2. The COG and LOG must remain w/in the BOS for an object to remain stable
3. The wider the BOS, the more stable the object
4. When the COG is no longer over the BOS, the object will fall
5. Stability increases as the BOS is widened in the direction of the force
6. The greater the mass of the object, the greater the stability
7. The greater the friction between the supporting surface and BOS, the more stable the body will be
8. People have better balance while moving if they focus on a stationary object, not a moving object
239
What is a First Class Lever?
The axis is located between the force and the resistance. (FAR)
Ex: Seesaw
Atlanto-occipital joint
Intervertebral joints
240
What type of lever is used to maintain posture or balance?
First Class
241
What is a Second Class Lever?
The resistance is in the middle, with the axis at one and the force at the other end. (ARF)
Ex: Wheelbarrow
Ankle PF muscles
242
What is a Third Class Lever?
The force is in the middle, with resistance and the axis at the opposite ends (AFR)
Ex: Person moving one end of a boat toward or away from a dock
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What is the most common type of lever in the body?
Third Class
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What is the advantage of a third class lever?
Speed and Distance
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What is the advantage of a second class lever?
Force Advantage (large weights can be supported or moved by a smaller force)
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In a third class lever, is the resistance arm or the force arm longer?
The resistance arm is always longer than the force arm. It requires more force but moves a larger distance.
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What 2 factors can change the lass of a lever?
Weight and Direction of movement
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What is Mechanical Advantage?
The ratio between the force arm and the resistance arm.
MA = FA / RA
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If Mechanical Advantage is great, is more or less force needed?
Less
