Understanding First, Second, and Third-Class Levers

Fulcrum between motive and resistive forces.

First-Class Lever

the skull and plantar flexion of the ankle act as __ lever systems

first class lever

Teeter-Totter is an example of what lever system

first-class lever system.

Distance from fulcrum to force application point.

Moment Arm

Increased force from longer moment arm gives a __

Force Advantage

Speed of movement along lever's length.

Linear Velocity

Direction Change in a first class lever system

Opposite directions for motive and resistive forces.

Desrcibe the __ class lever system involved with elbow extension (motive, resistive, fulcrum)

first class

The elbow is the fulcrum.

The triceps muscle provides the motive force.

The weight of the forearm is the resistive force.

Resistive force between fulcrum and motive force.

Second-Class Lever

levers of the second-class are always used to gain an advantage in ___

force production.

A push up is a ___ class lever sysem. The fulcrum, resistive force, and motive forces are..

second class lever

Fulcrum at toes

resistance from gravity

motive force from the hands

Motive force between fulcrum and resistive force.

Third-Class Lever

Third-class lever systems are used to gain advantage in ___

linear range of motion and velocity

Knee Flexors are an example of what class lever system

third-class lever system.

First class levers are classified as versatile because....

First-class levers can perform all machine functions.

Resistance Direction in second class levers

The resistance is moved in the same direction as the applied force

Third-class levers optimize __ and __ in the human body

motion and speed

Location of the ___ affects lever function and efficiency.

Axis of Rotation

All points on a rigid segment travel their respective distances in the same amount of time in what class lever system

first class

Longer __ arm increases mechanical advantage.

moment

Because the musculoskeletal system is designed for increased linear range of motion and velocity many human movements are classified as what class of lever system

Many human movements resemble third-class levers

Arrangement of moment arms, resistive force, and motive force in 3rd class lever systems

the moment arm for the motive force will always be less than the moment arm for the resistive force.

Arrangement of moment arms, resistive force, and motive force in 2nd class lever systems

the moment arm for the motive force will always be greater than the moment arm for the resistive force.

Arrangement of moment arms, resistive force, and motive force in 1st class lever systems

The moment arms for the forces are the same length.

The specific use of the first-class lever in terms of the four functions of a machine depends upon the exact location of the ...

axis of rotation/fulcrum