Three class of levers:
• First-Class Levers: o Fulcrum in the middle, between the effort and the resistance. o Examples:
The resistance is on the head, the fulcrum is the joint and the effort/resistance is the muscles that are attached to the skull such as the neck muscles.
• Second-Class Levers: o Now, resistance is in the middle between the fulcrum and the effort (applied.) o Examples: