Week 1- Kinetics of Human Movement

Question 1

Kinetics

Answer 1

A branch of the study of mechanics that describes the effect of forces on the body

Question 2

Force

Answer 2

Push or pull that can produce, arrest, or modify movement

Question 3

Load

Answer 3

Force acting on the body

Question 4

How do healthy tissues respond to changes in structure and shape

Answer 4

Typically able to partially resist changes in structure and shape

Question 5

Stress

Answer 5

Force generated as a tissue

resists deformation

Question 6

Strain

Answer 6

Ratio of a tissue’s deformed

length to its original length

Question 7

Regions of the Stress-Strain Curve

Answer 7

• Nonlinear region
• Linear region
• Elastic region
• Yield point
• Plastic region’
• Ultimate failure point

Question 8

Nonlinear region of the Stress-Strain Curve

Answer 8

• Unloading, or “uncrimping” of tissue

- Up to ~2% of strain

Question 9

Linear/elastic region of the Stress-Strain Curve

Answer 9

• Physiologic upper limit of tissue strain
• Experience stretch
• If strain < 4%, tissue will return to original length

Question 10

Yield point of the Stress-Strain Curve

Answer 10

The change in length is reversible

Question 11

Plastic region of the Stress-Strain Curve

Answer 11

Change in length is NOT reversible

Question 12

Ultimate failure point of the Stress-Strain Curve

Answer 12

Microfailure accumulates until irreversible deformation takes place

Question 13

Tension

Answer 13

Equal and opposite loads applied away from the surface of a structure

Question 14

Compression

Answer 14

Equal and opposite loads applied toward the surface of a structure

Question 15

Shear

Answer 15

Opposing loads applied parallel to the surface of a structure

Question 16

Torsion

Answer 16

Opposing loads are applied to

the surface of a structure resulting in twisting about an internal axis

Question 17

Bending

Answer 17

Combination of three or more loads applied to a structure, causing it to bend about an axis external to itself

Question 18

Combined forces

Answer 18

Combination of two or more loading modes applied to a structure at the same time

Question 19

Viscosity

Answer 19

Ability of a material to resist flow and dampen shear forces

Question 20

Elasticity

Answer 20

Property of a material demonstrated by its ability to return to its original length after the removal of a deforming force

Question 21

Viscoelasticity

Answer 21

• Property of a material expressed by a changing stress-strain relationship over time
• Exhibited by all body tissues in which the properties of viscosity & elasticity are combined

Question 22

Time-Dependent Properties

Answer 22

• Creep
• Hysteresis
• Stress-relaxation

Question 23

Creep

Answer 23

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

Question 24

Hysteresis

Answer 24

- Lag of an effect when
forces acting upon a
material are changed
- Energy is often lost
as heat

Question 25

Stress-relaxation

Answer 25

Decrease in the stress within a structure in the presence of a constant strain

Question 26

Internal force

Answer 26

Produced from structures within the body (active or passive)

Question 27

External force

Answer 27

Produced by forces outside of the body (eg. gravity, physical contact, etc.)

Question 28

Internal torque

Answer 28

Product of the internal force (muscle) and internal moment/lever arm

Question 29

Internal Moment Arm

Answer 29

Perpendicular distance between axis of rotation and the internal force

Question 30

External Torque

Answer 30

Product of external force (eg. gravity) and the external moment arm

Question 31

External Moment Arm

Answer 31

Perpendicular distance between axis of rotation and the external force