In biomechanics, which lever class has the load located between the fulcrum and the effort?

• A. Class I
• B. Class III
• C. Class II
• D. Class IV

Answer: (C)

In lever systems the arrangement of the fulcrum, load, and effort determines the class. When the load sits between the fulcrum and the effort, that is a second-class lever. A wheelbarrow is the classic example: the wheel is the fulcrum, the load sits in the barrow between the wheel and the handles where you apply force, so the load is between the pivot and your effort, providing a mechanical advantage. In biomechanics, standing on tiptoes illustrates this: the ankle acts as the fulcrum, body weight is the load between that pivot and the calf muscle force applied at the heel. The other lever types place the effort between the fulcrum and load (first-class), or place the load at the end with the effort at the other end (third-class). So the described setup corresponds to the second-class lever.