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

Which of the following is an example of a class 1 lever?

1. Elbow flexion

2. Seesaw, nodding your head back and forth

3. Standing on the balls of your feet

4. Throwing a ball

The correct answer is: Seesaw, nodding your head back and forth

A class 1 lever is characterized by the fulcrum being located between the effort and the load. In the context of nodding your head back and forth, the fulcrum is the atlanto-occipital joint, where the skull pivots on the atlas (the first cervical vertebra). The effort comes from the neck muscles as they contract to tilt the head, while the load is represented by the weight of the head itself. This arrangement clearly illustrates the class 1 lever system, where the fulcrum is central and allows for efficient movement of the head through flexion and extension. In contrast, elbow flexion represents a class 3 lever where the effort is applied between the fulcrum (the elbow joint) and the load (the weight of the forearm and hand). Standing on the balls of your feet describes a class 2 lever, where the load (weight of the body) is between the fulcrum (the toe joints) and the effort (muscles in the calves). Throwing a ball involves multiple levers and complex movements rather than a single class 1 lever system. Thus, the example of nodding the head back and forth accurately aligns with the definition of a class