Biomechanics

Question 1

Lever

Answer 1

A rigid bar (bone) that moves around an axis when a force is applied to overcome resistance

Question 2

Fulcrum/Axis (A)

Answer 2

The fixed point which the lever rotates around

Question 3

Force (F)

Answer 3

Effort (muscle) that causes the lever to move

Question 4

Resistance (R)

Answer 4

A force that hinders motion
•Weight
•Gravity

Question 5

Force arm/Lever Arm

Answer 5

The distance of the force to the fulcrumo

Question 6

Resistance arm

Answer 6

The distance of the resistance to the axis

Question 7

Levers

•1st Class

Answer 7

Fulcrum lies between the force and the resistance
•Designed for balance

   F                R
                A         •Crowbar or seesaw •Head sitting on the cervical spine

Question 8

Levers

•2nd Class

Answer 8

Resistance lies closer to the fulcrum than the force
•Advantage is Power

           R            F A •Wheelbarrow •The ball of a foot (A) serves as the axis of rotation as the ankle plantar flexors apply force to the calcaneous (F) to lift the resistance of the body at the tibial articulation (R) with the foot

Question 9

Levers

•3rd Class

Answer 9

Force is applied closer to the fulcrum than to the resistance
•Advantage is ROM (distance)
•Most of the levers in the body
Screen door
•Elbow is the axis (A) as the biceps force (F) moves the forearm (R)