Biomechanics: Chapter 1 & 4

Front 1

Osteokinematics

Back 1

The term used to describe the movement between bones

Front 2

Arthrokinematics

Back 2

The term used to describe the movement between the joint surfaces of bones

Front 3

Closed Kinetic Chain

Back 3

describes a position where the distal segment is fixed

Front 4

Open Kinetic Chain

Back 4

describes a position where the distal segment is free to move

Front 5

Closed packed Position

Back 5

unique position within most joints of the body where the articular surfaces are most congruent and the ligaments are maximally taut.

Front 6

What is the Sliding Filament theory?

Back 6

Active force is generated as actin filaments slide past the myosin filaments, resulting in contraction of an individual sarcomere.

Front 7

Loose-packed position

Back 7

places within most joints of the body where the articular surfaces are least congruent and the ligaments are slackened

Front 8

Mechanical advantage

Back 8

ratio of the internal moment arm to the external moment arm

Front 9

Internal Moment Arm

Back 9

distance between the axis of rotation and the perpendicular intersection with a muscle force

Front 10

External Moment Arm

Back 10

distance between the axis of rotation and the perpendicular intersection with a external force

Front 11

Agonist muscle

Back 11

muscle or muscle group that is most directly related to the initiation and execution of a particular movement

Front 12

Creep

Back 12

a progressive strain of a material when exposed to a constant load over time

Front 13

Leverage

Back 13

relative moment arm length possessed by a particular force

Front 14

Viscoelasticity

Back 14

property of a material expressed by a changing stress-strain relationship over time.

Front 15

Translation (Glide and Slide)

Back 15

linear motion in which all parts of a rigid body move parallel to and in hte same direction as every other point in the body.

Front 16

Antagonist muscle

Back 16

muscle or muscle group that has the action opposite to a particular agonist muscle.

Front 17

Kinetics

Back 17

branch of mechanics that describes the effect of forces on the body.

Front 18

Shear

Back 18

forces on a material that act in opposite but parallel directions

Front 19

Stiffness

Back 19

ratio of stress (force) to strain (elongation) within an elastic material

Front 20

Strain

Back 20

ratio of a tissue's deformed length to its original length

Front 21

Plasticity

Back 21

property of a material demonstrated by remaining permanently deformed after removal of a force

Front 22

Force-couple

Back 22

interaction of two or more muscles acting in different linear directions, but producing a torque in the same rotatory direction

Front 23

First Class Lever

Back 23

the axis is between the opposing forces (RAE). MA can be less than, equal or greater then 1 depending on the location of the axis.

Front 24

Second Class Lever

Back 24

the resistance is between the axis and effort arm (ARE). MA is always greater than 1

Front 25

Third Class Lever

Back 25

the effort is between the axis and resistance arm (AER). MA is always less than 1

Front 26

Equilbrium

Back 26

when the sum of the internal and external forces acting on a lever are equal.

Front 27

In the elastic zone when the strain is removed from the structue what happens to its length?

Back 27

It returns to normal

Front 28

Given the following information for a first class lever: R= 5, RA=10, E=2, EA=15. What direction would the system move, clockwise or counter-clockwise if the Resistance force is applied to the left of the axis?

Back 28

Counterclockwise

Hint 28

Determine the torques for both forces by multiplying the force times the distance. Which ever one is larger will ditate the motion the lever will move. Since in this case the Resistance is to the left of the axis and has a torque of 50 which is greater then the torque of the Effort which is 30, the lever will move in a counterclockwise direction.

Front 29

Lever systems utilize what kind of force system?

Back 29

Parallel

Hint 29

Since the Resistance and Effort force are applied to the same lever and are parallel to one another.

Front 30

When concurrent forces are applied to an object, what do they create?

Back 30

Resultant force

Front 31

What class of lever system always has a Mechanical Advantage that is greater than 1?

Back 31

Second

Front 32

Define Mecahnical Advantage

Back 32

Measure of the efficiency of the lever ( the relative effectiveness of the effort compared to the resistance).

Front 33

Define Moment Arm.

Back 33

Shortest distance b/t the action line and the jt axis and is found by measuring the length of a line drawn perpendicular to the force vector, intersecting the joint axis.

Front 34

If the moment arm of a constant force increases what happens to the amount of torque that is produced?

Back 34

It increases

Front 35

The Translatory force is applied _______________ to the lever system.

Back 35

Parllel

Front 36

The Rotary force is applied ________________ to the lever.

Back 36

Perpendicular

Front 37

Translatory and Rotary forces are examples of what kind of force system?

Back 37

Concurrent

Front 38

Define Center of Gravity

Back 38

A point within a object where it mass is evenly distrubted.

Front 39

Where is the center of mass located in an upright human body?

Back 39

Just anterior to the second sacral vertebraa

Front 40

Define base of support.

Back 40

defined as the area between the feet and ground where the centre of pressure can be maintained during stance.

Front 41

What is Newton's first law.

Back 41

A body remains at rest or in constant linear velocity except when compelled by an external force to chage its state.

Front 42

What is Newton's second law.

Back 42

The linear acceleration of a body is directly proportinal to the force causing it, takes place in the same direction in which the force acts, and isinversely proportional to the mass of the body.

Front 43

Define Newtow's third law.

Back 43

For every force there is an equal and opposite directed force

Front 44

Define Passive length-tension

Back 44

Ocurrs when the parallel and series elastic components are stretched within a muscle.

Front 45

Define Active length-tension

Back 45

The force generated by a muscle in response to a stimulus from the nervous system.

Front 46

Define Resting (optimal) length

Back 46

The length that allows the greatest number of cross-bridge attachments and, therefore, the greatest potential active force.