West Ada School District · Web viewIn a 1st class lever, the fulcrum list between the muscle and...
3
Biomechanics: LEVERS A lever is a _______________ with a fixed point around which it rotates when an external force is applied. The fixed point is called its _______________________________(the center of a joint) Circle the fulcrum from the pictures on your worksheet Rotary motion occurs in _________ different planes. Look at the skeleton in front of you. Move the arm into flexion and extension. 1. Where is the axis or rotation (the point in which the lever rotates)? 2. What plane is the axis of rotation(the screw) in? 3. Therefore, the axis of rotation for flexion and extension movements is in the ______ plane. 4. The axis of rotation for ab/adduction is in the ___________ plane There are ______________________ each determined by the relative location of its axis, force and resistance. The first 2 classes are seen primarily outside the body. EX: ____________________________ They enable us to ___________________________________ The motive force acts farther away from the axis of rotation, allowing smaller forces to easily move large amounts of resistance (weight) We use a relatively ______________amount of force at the end of a long lever arm to move a relatively large force at the end of _____________ lever arm. Think wheelbarrow: if you put a 100 lb rock towards the back of the bucket it is going to be harder or easier to lift? Why? 1 st class lever In a 1 st class lever, the fulcrum list between the muscle and the load. Using the materials in front of you, build a 1 st class lever (your finger will have to be used) Draw it on your worksheet
Transcript of West Ada School District · Web viewIn a 1st class lever, the fulcrum list between the muscle and...
Biomechanics:LEVERS
A lever is a _______________ with a fixed point around which it rotates when an external force is applied. The fixed point is called its _______________________________(the center of a joint)
Circle the fulcrum from the pictures on your worksheet
Rotary motion occurs in _________ different planes. Look at the skeleton in front of you. Move the arm into flexion and extension.
1. Where is the axis or rotation (the point in which the lever rotates)?2. What plane is the axis of rotation(the screw) in?3. Therefore, the axis of rotation for flexion and extension movements is in the ______ plane.4. The axis of rotation for ab/adduction is in the ___________ plane
There are ______________________each determined by the relative location of its axis, force and resistance.
The first 2 classes are seen primarily outside the body. EX: ____________________________
They enable us to ___________________________________ The motive force acts farther away from the axis of rotation, allowing smaller forces to easily move large amounts of resistance (weight)
We use a relatively ______________amount of force at the end of a long lever arm to move a relatively large force at the end of _____________ lever arm.
Think wheelbarrow: if you put a 100 lb rock towards the back of the bucket it is going to be harder or easier to lift? Why?
1 st class lever
In a 1st class lever, the fulcrum list between the muscle and the load.
Using the materials in front of you, build a 1st class lever (your finger will have to be used)
Draw it on your worksheet
1st class lever of body: color
2 nd Class Lever:
In a 2nd class lever, the load lies between the joint and the fulcrum effort/force
Using the materials in front of you, build a 1st class lever (your finger will have to be used)
Draw it on your worksheet
2nd class levers in the body: Color
3 rd Class Levers
In a 3rd class lever, the effort/force lies between the fulcrum and the load
Using the materials in front of you, build a 1st class lever (your finger will have to be used)
Draw it on your worksheet
3rd class levers in the Body Color
What would be more difficult:
Holding a 30 lb weight with elbow at 90 degrees of flexion or with elbow extended and shoulder at 90 degrees of flexion.
WHY? Answer in terms of lever length
