Planes and axis, levers Flashcards
What is the FULCRUM?
point of movement or pivot
What is the LOAD?
weight or resistance that the lever must move
What is the EFFORT?
muscular force to move the load
What is MECHANICAL ADVANTAGE?
measures the effiency of a lever
Formula to work out mechanical advantage
MA= effort arm// load( resistance) arm
What are LEVER SYSTEMS?
a rigid bar that turns about an axis to create movement
1st class lever
Fulcrum in middle
load on the left
effort on the right pointing down
Examples in the body where a 1st class lever occurs
> elbow (extension)
>neck
Sporting examples for 1ST CLASS LEVER
> throw in in football
>throwing a ball
Advantages of a 1ST CLASS LEVER
> strong
stable
increasing the length of lever increases ma
Disadvantages of 1ST CLASS LEVER
> slow acting movement
>limited flexibility
2nd class lever
Load in the middle
fulcrum on the left
effort on the right pointing upwards (long effort arm so HIGH MA)
Examples in the body where a 2ND CLASS LEVER is present
> ankle
|»_space;plantar/ dorsi flexion
Sporting examples of 2ND CLASS LEVER
> ice skating
dunk shot in basketball
sprinter leaving the blocks
lifting heavy weights
Advantages of 2ND CLASS LEVER
+HIGH mechanical advantage
+strongest lever effort arm is longer than load arm
Disadvantages of 2ND CLASS LEVER
- slow acting movement
- limited flexibility
3rd class lever
effort in the middle pointing upwards
fulcrum on the left
load on the right pointing down
Examples of 3RD CLASS LEVER in the body
> knee
hip
elbow (flexion)
> abduction
adduction
rotation
Sporting examples of 3RD CLASS LEVER
> tennis forearm
>upwards phase of a bicep curl
Advantages of 3RD CLASS LEVER
+Large range of movement
+Movement is fast
+Increase length of lever decrease MA
Disadvantages of 3RD CLASS LEVER
-the amount of force applied must always exceed weight of load
LOW MA longer load arm than effort arm
What is a PLANE?
an imaginary line that splits the body in two and depicts the direction of movement
What is an AXIS?
a line about which the body rotates
Description of FRONTAL plane and movement
side to side
>adduction, abduction
