Levers

Question 1

Levers

In order for a body part to move, the appropriate bones and muscles need to work in partnership, as a series of levers.
It has 4 components:

Answer 1

• Fulcrum/pivot – point at which the lever rotates
• Resistance/load – force applied by the lever
• Effort – the force applied by the user
• Lever - bone

Question 2

Fulcrum (definition)

Load/Resistance (definition)

Effort (definition)

Answer 2

The joint involved in the movement

The weight that is being moved e.g. dumbbell, or the body itself

Is the muscle acting as the agonist

Question 3

First Class Lever

2 things about it?
Locations in the body?

Sporting Example with all parts named

Answer 3

“EFL”

• Fulcrum lies between the effort and resistance/load
• Effort Arm and Load Arm are equal = no mechanical advantage

Only 2 examples in the body:

        - Neck – moving backwards and forwards
       - Elbow during extension

Sporting Example – When throwing the javelin:

   - Effort = Tricep Brachii provides the effort to extend at the elbow
   - Fulcrum = Elbow Joint
   - Load = Javelin

Question 4

Second Class Levers

3 things about it?
Locations in the body?

Sporting Example with all parts named

Answer 4

“ELF”

• Load/Resistance lies between the effort and the fulcrum
• Larger effort arm, smaller load arm = Mechanical Advantage
• Mechanical Advantage means if can lift a relatively heavy load

Only one example in the body:

       - Ball of the foot

Sporting example – When jumping:

      - Effort = gastrocnemius
      - Fulcrum = ball of the foot
      - Load = body weight

Question 5

Third Class Levers

4 things about it?
Locations in the body?

Sporting Example with all parts named

Answer 5

“FEL”

• Effort is between the fulcrum and the load
• This is the most common and, therefore, acts for all other joints in the body
• Mechanical Disadvantage because Load arm is bigger than effort arm therefore can move a lesser load
• Large load arm means there is a greater range of movement of speed
  E.g. knee flexion and extension

Sporting example – upward phase of bicep curl:

    - Effort = biceps brachii
     - Fulcrum = Elbow Joint
     - Load = dumbbell

Question 6

What is MECHANICAL ADVANTAGE ?

Answer 6

SECOND CLASS
- effort arm is greater than the load arm
- large load / small effort
- slower

Question 7

What is MECHANICAL DISADVANTAGE ?

Answer 7

THIRD CLASS
- load arm is greater than effort arm
- small load / large effort
- faster