Differentiate between 3 classes of Levers and give an example of each in the human Body.

Question 1

Class 1 Lever

Answer 1

• Definition: The fulcrum (axis) is located between the effort (force applied) and the load (resistance).
• Example in the Human Body: The head and neck act as a Class 1 lever when nodding.
  1. Fulcrum: The atlanto-occipital joint (where the skull meets the spine).
  2. Effort: The neck muscles pulling downward.
  3. Load: The weight of the head.

Question 2

Class 2 Lever

Answer 2

• Definition: The load (resistance) is positioned between the fulcrum and the effort.
• Example in the Human Body: The foot acts as a Class 2 lever during a calf raise.
  1. Fulcrum: The ball of the foot.
  2. Effort: The calf muscles pulling upward through the Achilles tendon.
  3. Load: The weight of the body.

Question 3

Class 3 Lever

Answer 3

• Definition: The effort is located between the fulcrum and the load.
• Example in the Human Body: The arm acts as a Class 3 lever during bicep curls.
  1. Fulcrum: The elbow joint.
  2. Effort: The contraction of the biceps muscle.
  3. Load: The weight in the hand.