Biomechanical Principles and Levers

Question 1

What does a lever consist of

Answer 1

Fulcrum
Load
Effort

Question 2

What represents the levers

Answer 2

Bones

Question 3

What presents joints

Answer 3

Fulcrums

Question 4

What represents the effort

Answer 4

The muscle

Question 5

What represents the load

Answer 5

The weight of body part being moved

Question 6

What are the three types of levers

Answer 6

First class lever
Second class lever
Third class lever

Question 7

What does each classification of the levers depend on

Answer 7

The position of the fulcrum, load and effort in relation to each other

Question 8

What is located on the centre of a first class lever

Answer 8

The fulcrum

Question 9

What are the two examples of first class levers in the body

Answer 9

Movement of head and neck during flexion and extension
Extension of the elbow

Question 10

What is located in the middle of a second class lever

Answer 10

The load

Question 11

Give an example of a second class lever

Answer 11

Plantar flexion of the ankle

Question 12

What is located in the middle of a third class lever

Answer 12

The effort

Question 13

Give examples of third class levers in the body

Answer 13

Hip, knee and elbow flexion

Question 14

What is the effort arm

Answer 14

The length of the line between where the fulcrum and effort are labelled

Question 15

What is the load arm

Answer 15

The length of the line between where the fulcrum and the load are labelled

Question 16

What is a mechanical disadvanatge

Answer 16

-When the load arm of a lever is longer than the effort arm
-the lever system cannot move as heavy a load but can do it faster
-large range of movement

Question 17

What is mechanical advantage

Answer 17

-When the effort arm is longer than the load arm
-means that the lever system can move a large load over a short distance and requires little force
-Small range of movement
-difficult to generate speed and distance

Question 18

What is linear motion

Answer 18

Motion in a straight or curved line, with all body parts moving the same distance at the same speed in the same direction

Question 19

Give an example of linear motion

Answer 19

• 100m athlete will travel with linear motion in a straight line during their race
• 200m athlete will travel with linear motion in a curved line when running the bend

Question 20

What is inertia

Answer 20

The resistance an object has to a change in its state of motion

Question 21

What is Newton’s first law of inertia

Answer 21

A force is required to change the state of motion of an object

Question 22

What is Newton’s second law of acceleration

Answer 22

The magnitude (size) and direction of the force determines the magnitude and direction of the acceleration on an object

Question 23

What is Newton’s third law of motion

Answer 23

For every action (force) there is an equal opposite reaction (force)

Question 24

Give a sporting example of Newton’s first law

Answer 24

In the high jump, the athlete runs horizontally towards the bar and then changes their state of motion at take-off when they travel vertically to try and clear the bar

Question 25

Give a sporting example of Newton’s second law of acceleration

Answer 25

To provide the acceleration at the start of a sprint race an athlete will have to apply a large force internally with their gluteals, quadriceps and gastrocnemius as they drive forward

Question 26

Give a sporting example of Newton’s third law of motion

Answer 26

At the start of a sprint race the athlete pushes back in the blocks as hard as possible and the blocks push forward on the athlete and provides forward acceleration on the athlete

Question 27

What is ground reaction force

Answer 27

The equal and opposite force exerted on a performer who applies a muscular force on the ground

Question 28

What is a scalar quantity

Answer 28

When measurements are described in terms of just their size or magnitude

Question 29

Give examples of scalar quantities

Answer 29

Speed, distance, mass, temperature

Question 30

What is speed

Answer 30

The rate of change of position and can be calculated by speed = distance/time

Question 31

What is distance

Answer 31

The length of the path a body follows when moving from one position to another

Question 32

What is the centre of mass

Answer 32

• point of balance
• due to the irregular shape of human and it’s constant motion it is hard to identify this point
• e.g. raising your arm in the air raises the centre of mass to keep the body balance
• COM is usually in between the hip region when standing

Question 33

What is the line of gravity

Answer 33

This is the line extending vertically downwards from the centre of mass and should be central over the base of support to increase stability

Question 34

What factors affect your stability

Answer 34

• height of the centre of mass
• position of the line of gravity
• area of the support base
• Mass of the performer

Question 35

What does the area of support base refer to

Answer 35

The amount of contact points of the person

Question 36

How does lowering you centre of mass affect stability

Answer 36

It increases stability. A low stance makes it harder for an opponent to push you over

Question 37

What is the mechanical advantage of a second class lever

Answer 37

• can generate much larger forces

Question 38

What is the mechanical disadvantage of second class levers

Answer 38

• slow
• limited range of movement

Question 39

What is the mechanical advantage of a first and third class lever

Answer 39

• large range of movement
• any resistance can be quickly moved

Question 40

What is the mechanical disadvantage of first and third class levers

Answer 40

Cannot apply much force to move an object