College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Which activity is an example of a class 2 lever?

1. Raising the arm

2. Standing on the balls of your feet

3. Using a shovel

4. Pushing a swing

The correct answer is: Standing on the balls of your feet

In biomechanics, a class 2 lever is characterized by the load being located between the fulcrum and the effort. This configuration allows for a mechanical advantage, making it easier to lift heavier weights with less effort. When standing on the balls of your feet, the toes act as the fulcrum, the body weight creates the load, and the calf muscles apply the effort to raise the heel. This arrangement exemplifies a class 2 lever, as the load (body weight) is indeed positioned between the fulcrum (toes) and the effort (calf muscles). In contrast, the other options represent different lever classes. Raising the arm is an example of a class 3 lever, where the effort is placed between the fulcrum (shoulder joint) and the load (weight of the arm). Using a shovel generally illustrates a class 1 lever because the effort is applied on one side of the fulcrum (the shovel's pivot point) while the load is on the other. Pushing a swing is also indicative of a class 1 lever, where the swing's pivot acts as the fulcrum, with the force applied at one end and the swing’s weight at the other.