6305: Test 2: Analysis Of Human Motion

Front 1

What type of motion?

Back 1

linear/translatory

Front 2

–
The number of independent movements allowed at a joint.
–
A joint can have up to three degrees of translatorymotions and three degrees of rotatorymotion.

Back 2

degrees of freedom

Front 3

–
Describes the motion that occurs between the articular surfaces of the joints.
–
Three movements: roll, slide, & spin

Back 3

arthokinematics

Front 4

For a convex-on-concave surface movement, the convex member rolls and slides in opposite direction

Back 4

ArthrokinematicPrinciples of Movement

Front 5

•
External Factors
–
Friction, air resistance, water resistance
•
Anatomic Factors:(modify motion of body segments)
–
Friction in joints
–
Tension of muscles, ligaments & fasciae
–
Anomalies of bones & joint structure
–
Presence of interfering soft tissue (fat)

Back 5

Factors that Modify Motion:

Front 6

types of motion

Back 6

Linear motionis the movement of all body parts in the same direction and at the same velocity.
•
Angular motionprovides for the circular rotation of an object around an axis,
•
Curvilinear motionis the movement of an object along a curved but not circular path

Front 7

Joint Motionis described in degrees of freedom of independent movement.
•
Jointsmove by rolling, sliding, spinning, and any combination of these motions.

Back 7

joint movement

Front 8

Push & pull exerted by one object on another that can produce, arrest, or modify movement.

Back 8

force

Front 9

Two consequences of force

Back 9

A force acting on a body has two effects, one to move it and two to rotate it.

Front 10

Normal forces that push 2 surfaces together

Back 10

comprehensive forces

Front 11

Streching force

Normal forces that push 2 surfaces together

Back 11

tensile force

Front 12

What type of force?

Back 12

comprehensive

Front 13

What type of force?

Back 13

tensile forces

Front 14

What type of force?

Back 14

shear

Front 15

Normal forces that act parallel to the surfaces
•
a stress which is applied parallel or tangential to a face of a material, as opposed to a normal stress which is applied perpendicularly.

Opposite directions

Back 15

shear/tangenital

Front 16

Principal types of force acting to move or stabilize the musculoskeletal system can be:

Back 16

–
Internal forces: produced from structures within the body
–
External forces: produced from structures outside the body

Front 17

What type of force?

Active: generated by muscles
–
Passive: generated by tension
•

Back 17

•
Internal Force
–

Front 18

what type of force?
–
Gravity pulling on body mass
–
External load, such as weights
–
Physical contact

Back 18

types of external force

Front 19

To describe force, you must know:
–

Back 19

To describe force, you must know:
–
Magnitude(spatial quality/extent of the force being exerted)
–
Direction(pull toward or away from the source)
–
Point of application(point at which the force is applied to an object)

Front 20

a graphical representation of a force; straight line drawn to scale, with an arrow pointing the direction of the force

Back 20

Vector –a graphical representation of a force; straight line drawn to scale, with an arrow pointing the direction of the force

Front 21

2+ forces acting along the same line, in same or opposite direction

Back 21

Linear Force
–

Front 22

Force action lines are parallel, in the same plane, and act at different points; same or opposite direction
•
E.g., lever system or 3-point bracing system; 3rdforce between them = stabilizer (law of action-reaction)

Back 22

parallel forces

Front 23

Two forces of different magnitudes & opposite direction applied simultaneously to an object

Back 23

Force Systems
•

Front 24

•
2+ Forces acting at angles from a common point of application

Back 24

CONCURRENT FORCES

Front 25

Example of Force Couple in the Body

Back 25

:Movement of the scapula

Front 26

•
____is not a standard term in mechanics.
•
____is used to designate the ability to produce or resist a force.
•
Muscle______ maybe measured in terms of the ability to overcome a resistance, to resist forces, or to support a load.

Back 26

strength

Front 27

is defined as the rate of doing work or work done per unit of time
= work / time

Back 27

power

Front 28

is defined as the product of force and displacement of object in direction of the force as the force is applied
= weight x distance x repetition
•

Back 28

Work

Front 29

The human body moves because the musculoskeletal system is a system of _________

Back 29

levers

Front 30

a rigid bar acted upon at two different points by opposing forces

They allow us to either do something with less effort or to increase the speed or force of an object being moved..

Back 30

lever

Front 31

Lever Components
•

Back 31

Lever Components
•
Fulcrum (axis) = A
•
Force Arm (force applied) = F
•
Resistance Arm (weight arm) = R

Front 32

What type of lever?

FIRST CLASS LEVER
–
Fulcrum is between the weight (R) and force (F) arms
•
Lever characteristics
–
balanced movement
•
axis is midway between force and resistance
•
e.g.: seesaw
–
speed and range of motion
•
axis is close to force
•
e.g.: elbow extension
–
force
•
axis is close to resistance

Back 32

first class lever

Front 33

•
This type of lever favors equilibrium.
•
This lever is used to gain either force or distance.
•
It is the most versatile of the three levers.
•
Frequently used for maintaining postures or balance.
•
Commonly used in orthotics, called a 3-point system for applying force.
•
Examples: seesaws, scissors, crowbars, & jacks

Back 33

first class lever

Front 34

What type of lever?

Back 34

first class lever

Front 35

What type of lever?

Weight (R) is between the fulcrum and force (F) arm

Back 35

second class

Front 36

What type of lever?

Back 36

second class

Front 37

lever provides a force advantage to support large weights or to be moved by a smaller force.
•
This type of lever favors the force of effort.
•
Force arm is always greater (longer) than the resistance arm.
•
ROM is sacrificed to gain force.
•
In the human body, this type of lever is seen when gravity is the force and muscles are the resistance.
•
E.g. wheelbarrow,Nutcracker,Paddle,

Back 37

Second Class Lever

Front 38

What type of lever?

Force (F) arm is between the fulcrum and weight (R) arm

Back 38

THIRD CLASS LEVER

Front 39

lever used to produce speed & distance of the distal segment of the body
–
What is gained in speed or distance is lost in force.
–
What is gained in force is lost in speed.
•
Force arm (FA) will always be shorter than the resistance arm (RA)
•
Designed to produce speed and distance of movement at the expense of force; allows minimal muscle shortening because the muscles insert near the joint
•
Most common lever type in the body.
•
Ex. Baseball bat, Boat paddle, Broom, Electric Gates, Fishing rod, Hockey stick, Mandible, Mousetrap (Spring-loaded bar type), Shovel (the action of picking or lifting up sand or dirt), Stapler, Tongs, Tweezers, Hammer, Tennis racket, The Human Arm

Back 39

third class lever

Front 40

rigid bar which moves around a fulcrum (axis) for motion

Back 40

bone

Front 41

in a leverage system when does movement occur

Back 41

Movement occurs when the force of muscle contraction is sufficient to overcome the resistance, which is at least the weight of the part being moved

Front 42

F-----A------R

Back 42

first class lever

Front 43

A------R-------F

Back 43

second class lever

Front 44

A-----F-------R

Back 44

third class lever

Front 45

What type of Lever?

Back 45

First Class Lever

Front 46

What type of lever?

Back 46

2nd class

Front 47

What type of lever?

Back 47

third class

Front 48

The principles of the ______are used to visualize the complex system of forces that produce rotary motion in the body –muscles, gravity, & physical contact.

Back 48

levers

Front 49

A lever is in balance or______ , when force x force arm = resistance x resistance arm

Back 49

equilibrium

Front 50

•
Refers to the efficiency of a lever.
•
Is the relationship between the length of the force arm (FA) and the length of the weight arm (RA)
MA = FA / RA
•
When only a small effort of force is needed to overcome a larger resistance, the lever is efficient.

Back 50

mechanical advantage

Front 51

: waste energy and force to gain speed and distance

Back 51

3rdClass Levers

Front 52

utilizes less force and energy to gain little speed or distance.

Back 52

2ndClass Levers:

Front 53

Majority of the human body levers are quite ________as far as force requirements are concerned, but they do provide a large amount of motion at the distal end.
•
Goal of human function is the placement or relocation of the distal segments of the body.

Back 53

inefficient

Front 54

the most constant force encountered by the body. It affects the stability of the body as well as the movement of the trunk, extremities & head.

Back 54

GRAVITY

Front 55

is enhanced by a low center of gravity, wide base of support, the gravity line at the center of the support, & heavy weight.

Back 55

Stability

Front 56

Any change in _____distribution results in a change in the center as well as line of gravity.

Back 56

WEIGHT

Front 57

•
is enhanced by a high center of gravity, narrow base of support, & light weight.
•

Back 57

Mobility

Front 58

--------can & does provide the force for motion.

Back 58

GRAVITY

Front 59

are easier to maintain when the base of support is increased or the center of gravity is lowered.

Back 59

Balance & Stability

Front 60

WHAT TYPE OF LEVER?

Used to gain force, distance, or stability

Back 60

FIRST CLASS

Front 61

The human body uses a system of _______to move. The -------of a muscle pull directly effects the force it is capable of producing.

Back 61

LEVER, EFFICIENCY

Front 62

WHAT TYPE OF LEVER?

Allows for support of large weights or for the weights to be moved by a smaller force
–
Utilizes less force and energy to gain little speed or distance.

Back 62

2ND CLASS

Front 63

WHAT TYPE OF LEVER?

–
Produces speed & distance of distal segment
–
Wastes energy & force to gain speed & distance

Back 63

3RD CLASS

Front 64

Changing the length of the force arm (FA) or resistance arm (RA) will make

Back 64

–
Movement easier or harder and
–
Lever more or less efficient.