Flashcards in Section 2 - Movement analysis Deck (19)
What is a lever ?
a solid bar that moves around a fixed point when force is applied to it
What are the 3 components to a lever ?
Fulcrum - (pivot) where the movement occurs usually a joint
Effort - (force) where the force is applied to one part of the effort
Load - (resistance) is at the other end working against the force of the effort
What is the 1st class and an example ?
Load - Fulcrum - Effort
head - joint between cranium & vertebra - back muscles
e.g. neck extension (heading in football)
What is the 2nd class and an example ?
Fulcrum - Load - Effort
toe joint - body weight - gastrocnemius
e.g. plantar / dorsi flexion (standing on toes to jump)
What is the 3rd class and an example ?
Load - Effort - Fulcrum
weight of hand + weight - force of bicep - elbow joint
e.g. elbow flexion (lifting a weight)
How do you calculate Mechanical Advantage ?
mechanical advantage = effort arm / weight arm
When does a first class lever have a mechanical advantage ?
if the fulcrum is closer to the load than the effort
Second class levers always have a mechanical advantage, why ?
the effort arm is always longer than the weight arm
Third class levers always have a mechanical disadvantage, why ?
the effort arm is always shorter than the weight arm
When does a first class lever have a mechanical disadvantage ?
if the fulcrum is closer to the effort than the load
What is a mechanical advantage ?
when a lever can move a large load with a small effort from the muscle
What is a mechanical disadvantage ?
a large effort from the muscles to move a small load
Where does movement happen ?
What are the 3 planes ?
sagittal - divides the body into left and right
transverse - divides the body into top and bottom
frontal - divides the body's front and back
What does movement happen around ?
What are the 3 types of axis ?
sagittal - runs through the body from front to back
longitudinal - runs through the body from top to bottom
transverse - runs through the body from left to right
What type of plane and axis does flexion / extension use ?
sagittal and transverse
e.g. tuck and pike somersaults, running, forward roll
What type of plane and axis does abduction / adduction use ?
frontal and sagittal