Biomechanics Quiz 4

Question 1

Devices for directly measuring joint angles:

Answer 1

1. Goniometer

2. Electrogoniometer

Question 2

range of motion can be measured as:

Answer 2

1. Maximum joint angle

2. Excursion: total movement

Question 3

What can restrictions in range of motion can impair?

Answer 3

performance

Question 4

Excessive or restricted range of motion can indicate what?

Answer 4

injury or disorder

Question 5

What is osteokinematics?

Answer 5

the motion bones relative to the three cardinal planes of the body (horizontal, sagittal, frontal)

Question 6

Osteokinematics: axis of rotation – located? example?

Answer 6

located: through the convex member of the joint
ex: shoulder

Question 7

Osteokinematics: angular degrees of freedom

Answer 7

“accessory movement”

Question 8

What is Arthrokinematics?

Answer 8

the motion that occurs between articular surfaces of joints.

Question 9

examples of Arthrokinematics

Answer 9

–Congruency
–Surface Area
–Guide

Question 10

Arthrokinematics: what is roll?

Answer 10

Multiple points along one rotating articular surface contact multiple points on another articular surface.

Question 11

Arthrokinematics: what is slide?

Answer 11

A single point on one articular surface contacts multiple points on another articular surface.

Question 12

Arthrokinematics: what is spin?

Answer 12

A single point on one articular surface rotates on a single point on another articular surface.

Question 13

One primary way that a bone rotates through space is by:

Answer 13

rolling of its articular surface against another bone’s articular surface.

“roll-and-slide”

Question 14

The rolling of the typically involves:

Answer 14

a concurrent, oppositely directed slide.

“roll and spin and slide”

Question 15

Musculoskeletal Torques:

moment arm

Answer 15

the perpendicular distance from an axis to the line of force

Question 16

Angular Kinetics: internal. produced from?

Answer 16

structures within the body

Question 17

Angular Kinetics: internal: active is generated by?

Answer 17

Generated by stimulated muscle, generally but not necessarily under volitional control.

Question 18

Angular Kinetics: internal: passive is generated by?

Answer 18

Generated by tension in stretched periarticularconnective tissues, including the intramuscular connective tissues, ligaments and joint capsules.

Question 19

Angular Kinetics: external. produced by? originate from?

Answer 19

forces acting outside the body.

originate from either:

1. gravity pulling on the mass of a body segment
2. an external load, such as a weight or physical contact

Question 20

Musculoskeletal Torque

Answer 20

a TORQUE rotates an object about an axis of rotation.

whereas force pushes and pulls object linearly

Question 21

TORQUE can be considered what in relation to force?

Answer 21

a rotatory equivalent to force.

Question 22

Moment Arm (MA):

Answer 22

Perpendicular distance between the joint axis of rotation and the force.

Question 23

Torque formula

Answer 23

Torque = force x MA

Question 24

Internal Torque formula

Answer 24

Internal Force x Internal MA (D)

Question 25

External Torque formula

Answer 25

External Force x External MA (D)

Question 26

Static equilibrium occurs when:

Answer 26

internal torque = external torque

Question 27

Musculoskeletal Torque: Joint angle can alter …

Answer 27

… the torque producing capabilities of muscle.

Question 28

The larger the moment arm

Answer 28

The smaller the resistance

Question 29

3 Types of Muscle Interaction:

Answer 29

1. Isometric
2. Concentric
3. Eccentric

Question 30

Isometric Activation

Answer 30

when a muscle is producing a pulling force while maintaining a constant length

*NOTE: the internal torque produces within a given plane at a joint is equal to the external torque; hence, there is no muscle shortening or rotation at the joint. (i.e. static equilibrium)

Question 31

Concentric Activation

Answer 31

a muscle produces a pulling force as it contracts (shortens).

*NOTE: , the internal torque at the joint exceeds the opposing external torque. The contracting muscle creates a rotation of the joint in the direction of the pull of the activated muscle.

Question 32

Eccentric Activation:

Answer 32

a muscle produces a pulling force as it is being elongated by another more dominant force.

*NOTE: the external torque around the joint exceeds the internal torque. The joint rotates in the direction dictated by the relatively larger external torque.