Levers

Question 1

Lever systems

Answer 1

• the coordination of our bones and muscles
• to create movement

Question 2

What are levers composed of

Answer 2

• F = a rigid structure hinged at 1 point
• L & E = 2 forces are applied at 2 other points

Question 3

4 components of a lever system

Answer 3

• lever
• fulcrum
• effort
• load/resistance

Question 4

In the human body - what are the levers

Answer 4

• The bone
• they are rigid and rotate around a fixed point

Question 5

In the human body what is the fulcrum

Answer 5

• The body’s fixed joints

Question 6

In the human body what is the effort

Answer 6

• The agonist muscle
• contraction of agonist muscle creates internal force/effort to move the bones they are attached to

Question 7

In the human body what is the load or resistance

Answer 7

• body part
• resistance to be moved

Question 8

2 main functions of levers

Answer 8

• to generate muscular effort and overcome a load
• to increase the speed of given movement

Question 9

If the effort is large enough to overcome the load then what happens

Answer 9

• movement of the levers occurs

Question 10

123

Answer 10

FLE

Question 11

Bicep curl - lever apply

Answer 11

• lever = radius and ulna
• fulcrum = elbow joint
• effort = biceps brachii
• load = weight / resistance of forearm

Question 12

First class lever system

Answer 12

• fulcrum is in the middle
• between the effort and the load

Question 13

Second class lever system

Answer 13

• load is in the middle
• between the fulcrum and the effort

Question 14

Third class lever system

Answer 14

• effort is in the middle
• between the fulcrum and the load

Question 15

Load arm

Answer 15

• the distance from the fulcrum to the load

Question 16

Effort arm

Answer 16

• the distance from the fulcrum to the effort

Question 17

Examples of a first class lever system

Answer 17

• skull joint when extending neck, e.g football header
• extension of the elbow in ah overarm throw

Question 18

Skull joint

Answer 18

• atlas

Question 19

Lever system - heading a ball/ neck extension

Answer 19

• fulcrum = atlas
• load = weight of head /ball
• effort = neck muscles e.g trapezius

Question 20

Extension of the elbow in an overarm throw - levers

Answer 20

• fulcrum = elbow joint
• load = resistance of ball/ resistance of forearm
• effort = triceps brachii

Question 21

Example of a second class lever

Answer 21

• ball of the foot when going into plantar flexion
• pushing up onto tip toes
• e.g take off phase in the high jump

Question 22

Levers - take off phase in high jump

Answer 22

• fulcrum = ball of foot, metatarsals and phalanges joint
• load = body weight/gravity
• effort = gastrocnemius and soleus

Question 23

Examples of third class levers

Answer 23

• kicking a football
• bicep curl

Question 24

Bicep curl - lever system

Answer 24

• Fulcrum = elbow joint when
• load = resistance of lower arm/ weight
• effort = biceps brachii ; agonist muscle

Question 25

When you kick a ball what are the 3 levers which are acting

Answer 25

- upper leg = pivoting about hip joint - lower leg = pivoting about knee - foot pivoting about your ankle

Question 26

Upper leg pivoting about hip joint - what muscle is this lever motion controlled by

Answer 26

Illiopsoas

Question 27

Lower leg pivoting about your knee - which agonist muscle controls this lever motion

Answer 27

Rectus femoris

Question 28

Foot pivoting about your ankle - what agonist muscle controls this lever motion

Answer 28

Tibialis anterior

Question 29

How to 3rd class levers act

Answer 29

- input force is applied closer to the fulcrum than the output force

Question 30

When we swing out leg backwards in preparation to kick your leg uses 3 other muscles which act in the opposite direction - what are these

Answer 30

- gluteus maximus - biceps femoris - gastrocnemius / soleus

Question 31

Where is the gluteus maximus located

Answer 31

- back of upper leg - pivoting about hip joint when

Question 32

Where is the biceps femoris located

Answer 32

- back of lower Leg - pivoting about knee joint

Question 33

Where is the gastrocnemius / soleus located

Answer 33

- back of lower leg - pivoting about ankle

Question 34

Using Practical Examples, explain how the elbow joint can act as a fulcrum for 2 different lever systems (4 marks)

Answer 34

- elbow joint works as the fulcrum in 1st class lever when performing an extension of the elbow in an overarm throw - elbow joint acts as the fulcrum in the middle - elbow joint works as the fulcrum in 3rd class lever during a bicep curl - where the effort is in the middle, in this case, the biceps brachii

Question 35

what do the best levers have

Answer 35

- LONG effort arm + SHORT load arm - LONG effort distance + SHORT load distance

Question 36

the greater the distance the effort or load from the fulcrum ...

Answer 36

- the more important the effort or load becomes

Question 37

why do longer levers generate more force

Answer 37

- load arm is longer - giving greater RoM and acceleration to projectiles, e.g tennis ball

Question 38

example of when being tall is an advantage

Answer 38

- taller athletes have longer levers (legs/arms) - in rowing

Question 39

example of when sports equipment gives an advantage with levers

Answer 39

- helps to increase the length of a lever/effort arm - e.g longer drive in golf

Question 40

what gives a mechanical advantage / disadvantage

Answer 40

length of effort and load arm

Question 41

mechanical advantage - 2nd class lever system

Answer 41

- load is between the fulcrum + effort - effort arm is always longer than load arm - effort is further away from fulcrum than load - so a small effort can move a large load - mechanical advantage

Question 42

Mechanical advantage - 2nd class lever example

Answer 42

- small effort can move a large load - = take off phase of a jump - relatively small effort produced by gastrocnemius and soleus - can drive a large weight of the performer off the ground

Question 43

Mechanical advantage - 2nd class lever = disadvantage

Answer 43

- only over a small distance - at the expense of velocity

Question 44

Mechanical disadvantage - 3rd class lever system

Answer 44

- effort is between fulcrum + load - load arm is longer than effort arm - it is never an advantage - because the effort arm can never be longer than the load arm - load is always further away from fulcrum than effort - always mechanical disadvantage - as a large effort is needed to move a small load

Question 45

Mechanical disadvantage - example

Answer 45

- kicking a ball - the ball is a small load - requires a large muscular effort from quadriceps to kick it

Question 46

Mechanical disadvantage - 3rd class lever - advantage

Answer 46

- 3rd class levers allow a greater RoM - allowing us to generate more momentum - and move a load at higher velocity

Question 47

is a 1st class lever mechanically advantaged or disadvantaged

Answer 47

- can be neutral, +, or - - depending on position of fulcrum - if it has long effort arm = advantage - if it has long load arm = disadvantage - if effort arm and load arm are equal = neutral

Question 48

lever systems - evaluate

Answer 48

- understanding lever system allows an athlete to manipulate their body to maximise performance - enables us to realise that some athletes are going to be better at specific sports due to height - e.g tall and talented - understanding how much effort is required to move a certain load allows an athlete to train their body efficiently

Question 49

tall and talented

Answer 49

- talent identification programme - helps identify rowers by those with long levers

Question 50

2 tennis players perform a serve - 1 is taller than the other. Evaluate mechanical advantage over each other

Answer 50

- taller player = longer effort arm = longer lever as effort arm is further from fulcrum than load = advantage in serve - taller player = needs more muscular effort to serve ball than shorter player = mechanical disadvantage - if taller player can create motion they will gain more momentum and generate more power = faster serve