Lever System (basic concepts of biomechanics) Physiotherapy class
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summary of the video with the time for reference:

1.Torque and Lever system
Leverrigid body
Fulcrumfixed point
Torque = Force x MA
Moment arm is always parpandicular distance from line of force to fulcrum

2.Lever System
FREE
First class fulcrum is in the center
Second class Resistance arm is in the center
Third class Effort arm is in the center
Effort arm always wins and resistance arm always looses

3.First class lever system
like a see saw
Resistance arm can be greater than, equal to, or less than effort arm
flexion extension of head at occiput
Abduction and adduction at shoulder joint

3.Second class lever system
Effort arm greater than the resistance arm
Ankle planter flexion
Elbow flexion with brachioradialis action

3.Third class lever system
Effort arm less than the resistance arm
Knee extension with quadriceps
Elbow flexion with biceps action

#centreofmass #centreofgravity