Muscular Leverage

Question 1

A lever consists of?

Answer 1

A rigid bar that pivots around a stationary pivot point (fulcrum)

Question 2

First class levers

Answer 2

Have the fulcrum in the middle, like a seesaw (nodding the head is an example of a first class lever, with the top of the spinal column as the fulcrum)

Question 3

Second class levers

Answer 3

Have a resistance in the middle with the fulcrum and effort on either side, similar to a load in a wheelbarrow where the axle and wheel are the fulcrum points. (Body acts as a second-class lever when one engages in a full-body push up or calf raise. Using the calf raise exercise is an example, the ball of the foot is the fulcrum, the body weight is the resistance, and the effort is applied by the calf musculature. )

Question 4

Third class levers

Answer 4

Have the effort placed between the resistance and the fulcrum. The effort always travels a shorter distance and must be greater than the resistance. Most limbs of the human body operate as third-class levers.

Example: human forearm; the fulcrum is the elbow, the effort is applied by the biceps branching muscle and the load is in the hand, such as a dumbbell when performing a biceps curl.

Another example: standing hamstring curl, whereby the knee joint is the fulcrum, hamstring muscle is the effort, and resistance is at the ankle.

Question 5

When trying to remember levers think of:

Answer 5

F-R-E-1-2-3. Fulcrum is in middle =(F,1) resistance is in the middle of the second class (R,2), with effort in middle for a third-class lever (E,3).