Lever Types

There are three different types of levers utilized in mammals. Each is characterized by the position of the fulcrum (pivot point) in relationship to the position the in-force of a muscle is applied to the power arm to balance the out force on the load arm or set the lever in motion. As seen earlier the lengths of the power and load arms determines the efficiency of the lever.

Type 1 lever - activate lever - reset lever

• the fulcrum is somewhere along the lever arm
• the in-force is applied in the opposite direction of the out-force movers the load arm

Type 2 Lever - activate lever - reset lever

• the fulcrum is at one end of the lever arm
• the in-force is applied at the opposite end of the lever arm
• the out-force moves in the same direction as the in-force

Type 3 Lever - activate lever - reset lever

• the fulcrum is somewhere along the lever arm
• the in-force is applied in the same direction as the out-force moves

Each of these types of levers is utilized when moving your body, but type three are the most common. Make sure you understand the difference between type 1 and type 3 levers. A key to understanding how these types of levers differ is to pay attention to the point of muscle attachment along the power arm (in-force) and the direction of movement of the load arm (out force). To help you understand where different types of levers are utilized when you move do the exercise on page 27 in your lab manual. It will be collected at the beginning of the laboratory. You may want to do the exercise while referring to this section of the tutorial.

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