Section 2 - Movement Analysis Flashcards
What is a lever?
A solid bar that moves around a fixed point when force is applied to it
What are the 4 components to a lever?
Lever Arm - bone or body part being moved about a point (straight line)
Fulcrum - the joint where the lever arm pivots (triangle)
Effort - the force applied by the muscles to the lever arm (arrow)
Load - resistance against the pull of the muscles on the lever arm - weight of body/ something being lifted (square)
What is the codes for going from 1st to 3rd class levers for the direction of the effort arrow?
Down 1st
Up 2nd
Up 3rd
Always points to the lever arm
What is the codes for what goes in the middle?
F
R/L
E
What is the 1st class and an example?
Load - Fulcrum - Effort
Elbow Extension (e.g football throw in)
What is the 2nd class and an example?
Fulcrum - Load - Effort
Planter flexion + Dorsiflexion at the ankle (e.g take off phase in long jump)
What is the 3rd class and an example?
Load - Effort - Fulcrum
Elbow flexion (e.g upward phase of bicep curl)
+ Flexion and Extension at shoulder, hip and knee
How do you calculate Mechanical Advantage?
mechanical advantage = effort arm / weight arm
What happens if a lever has a low mechanical advantage?
Will be able to move load quickly through a large range of movement.
What happens if a lever has a high mechanical advantage?
Will be able to move a large load with small effort from the muscles
But can only move the load short distances at low speeds
When does a first class lever have a high mechanical advantage?
If the fulcrum is closer to the load than the effort
When does a first class lever have a low mechanical advantage?
If the fulcrum is closer to the effort than the load
Does 2nd class levers have a high or low mechanical advantage , why ?
High mechanical advantage
The effort arm is longer than the weight arm
Do 3rd class levers have a high or low mechanical advantage, why?
Low mechanical advantage
Effort arm is shorter than weight arm
Where does movement happen?
Planes
