03 Classes of Levers

Class 1 the fulcrum is in the ______ of the effort and the load

middle

Give example of Class 1

Tricep extension at elbow
Seesaw

A good real-life example is a seesaw and a joint-based example would be the triceps muscle at the elbow. The fulcrum is the elbow, the triceps is on one side of the elbow and the load is placed in the hand on the other side of the elbow. This system is good for strength creation but has slower speed.

Second Class Lever: This lever system has the fulcrum and effort/force on ________ sides with the load in the middle.

opposite sides

Second class lever example

tip-toe, wheelbarrow

The classic joint we think of here is the ankle. The fulcrum is the MTP, the effort is the gastroc/achilles complex, and the load is the body weight in the middle. A real-life example would be a wheelbarrow. The fulcrum is the wheel, the load is in the wheelbarrow, and the effort or force comes from us lifting the handles. This lever system is great for strength, but again has less speed.

Third Class Lever: This lever system has the fulcrum and load on ______ sides and the effort/force in the ______.

opposite; middle

Third Class Lever examples

elbow flexion

The muscular example would be the biceps at the elbow as the tendon (effort/force) attaches distal to the elbow (fulcrum) and the load is in the hand. A real-life example would be holding something with tweezers. This lever system is better for quick movements.