Forces and movement in the human body

Question 1

Describe linear movement and how it is created

Answer 1

Linear movement is the movement of an object in a straight line. Force has to be applied at the centroid of an object.

Question 2

Describe angular movement and how it is created

Answer 2

Angular movement is the movement of an object in a circular motion. Force has to be applied away from the centroid of the body.

Question 3

Describe angular velocity

Answer 3

Rate at which a rotating body changes position

Question 4

Describe angular acceleration

Answer 4

Rate at which angular velocity changes

Question 5

What do each of the components of the lever systems represent?

Answer 5

Lever =  bone
Effort = muscle
Fulcrum = joints
Load = other forces (weight, gravity)

Question 6

Describe a 1st class lever system and give an example

Answer 6

Fulcrum is in the middle and the load and effort are situated on either side.
E.g = nodding your head

Question 7

Describe a 2nd class lever system and give an example

Answer 7

Fulcrum is to one end of the lever, with load in the middle and effort at the opposite end.
E.g = plantar flexion

Question 8

Describe a 3rd class lever system and give an example

Answer 8

Fulcrum is at one end of the lever, with effort in the middle and load at the other end.
E.g = bicep curl

Question 9

How do you calculate mechanical advantage and disadvantage of lever systems.

Answer 9

Effort arm length / load arm length
>1 = mechanical advantage
<1 = mechanical disadvantage

Question 10

Do first class lever systems have a mechanical advantage or disadvantage?

Answer 10

They can have either, depending on the arm lengths.

Question 11

Do second class lever systems have a mechanical advantage or disadvantage?

Answer 11

They always have a mechanical advantage (>1), so requires less effort to move the equivalent load

Question 12

Do third class lever systems have a mechanical advantage or disadvantage?

Answer 12

They always have a mechanical disadvantage (<1)

Require more effort to move the equivalent load, but they move at a greater speed and has a larger range of motion

Question 13

What are internal forces

Answer 13

Forces produced by muscles

Question 14

What are external forces

Answer 14

Forces made outside the body (being hit)

Question 15

How do tendons and ligaments help to prevent injury

Answer 15

They help prevent joints and muscles from being taken beyond their normal range of motion, helping to reduce injury

Question 16

Define stress

Answer 16

Pressure exerted on an object

Question 17

Define strain

Answer 17

The amount of deformation of a material caused by stress

Question 18

How can ligaments and tendons become damaged

Answer 18

Ligaments and tendons take a finite amount of stress and/or strain, but if the force is greater than their tensile, compressive or shear stress they become damaged

Question 19

Describe active movement

Answer 19

Movement carried out by the individual, with no help

Question 20

Describe passive movement

Answer 20

Movement carried out by someone/ something else

Question 21

What factors is range of motion affected by

Answer 21

Shape of joint
Ligaments
Length of muscle and tendon
Magnitude of force applied

Question 22

Define flexibility

Answer 22

Ability to move your joint, or series of joints, through the full ROM

Question 23

What factors affect flexibility

Answer 23

Age
Gender
Genetics
Use
Training
ROM

Question 24

Describe degrees of freedom

Answer 24

Degrees of freedom refer to the number of planes in which they can move
One degree of freedom = movement in one plane
Two degrees of freedom = movement in two planes
Three degrees of freedom = movement in three planes

Question 25

Define the following words:

1. Pronation
2. Supination
3. Radial deviation
4. Ulna deviation
5. Opposition

Answer 25

1. internal rotation of forearm/forefoot (palm up)
2. external rotation of forearm/forefoot (palm up)
3. abduction of the wrist
4. adduction of the wrist
5. combination of the thumb towards the fingertips

Question 26

Define the following words:

1. Dorsiflexion
2. Plantar flexion
3. Inversion
4. Eversion

Answer 26

1. flexion of the ankle
2. extension of the ankle
3. rotation in the frontal plane that moves the foot inwards
4. rotation in the frontal plane that moves the foot outwards