Levers Flashcards
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:
- Fulcrum/pivot – point at which the lever rotates
- Resistance/load – force applied by the lever
- Effort – the force applied by the user
- Lever - bone
Fulcrum (definition)
Load/Resistance (definition)
Effort (definition)
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
First Class Lever
2 things about it?
Locations in the body?
Sporting Example with all parts named
“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
Second Class Levers
3 things about it?
Locations in the body?
Sporting Example with all parts named
“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
Third Class Levers
4 things about it?
Locations in the body?
Sporting Example with all parts named
“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
What is MECHANICAL ADVANTAGE ?
SECOND CLASS
- effort arm is greater than the load arm
- large load / small effort
- slower
What is MECHANICAL DISADVANTAGE ?
THIRD CLASS
- load arm is greater than effort arm
- small load / large effort
- faster