Movement Analysis Flashcards
What’s an example of a first class lever?
The joint between the skull and the first vertebrae
What’s an example of a second class lever?
Heel joint
What’s an example of a third class lever?
Elbow joint
How do you remember the lever classes?
123 FLE
1 = Fulcrum in middle
2 = Load in middle
3 = Effort in middle
What lever class is plantar flexion?
2nd class
Which is the most common lever class?
3rd class
- Exam tip: if you don’t know which lever the movement is, guess 3rd class!!
What’s the load arm?
Distance from the fulcrum to the load
What’s the effort arm?
Distance from the effort to the fulcrum
How does mechanical advantage relate to the lever system?
When a lever’s effort arm is longer than its load arm, it has a high mechanical advantage
What does it mean to have a high mechanical advantage?
Levers can overcome large loads, requiring relatively low effort
What are the disadvantages of having a high mechanical advantage?
- Short range of motion at the joint
- Limited speed
What lever has the highest mechanical advantage?
2nd class lever
In which lever system does the effort usually act down?
1st class lever
What’s the equation for mechanical advantage?
Effort arm/load arm
What’s the plane for flexion and extension?
Sagittal plane
