Which movement involves rapid shaking?

The correct choice is based on the specific technique that embodies the concept of rapid shaking in massage therapy. Vibration is characterized by its quick, shaking movements, which can vary in intensity and speed. This technique is often used to stimulate the muscles and can have various effects, such as relaxing muscle tension, improving circulation, and enhancing overall bodily awareness.

In contrast, the other techniques listed serve different purposes. Petrissage involves kneading and squeezing, which aims to release muscle tension and improve circulation through deeper manipulation of the muscle tissue. Tapotement consists of rhythmic tapping or striking movements, which are more about stimulating the body rather than the rapid shaking associated with vibration. Effleurage utilizes long, gliding strokes that promote relaxation and are typically less intense than the methods that involve shaking or tapping. Thus, vibration is distinct in its emphasis on rapid movements, making it the correct answer to the question.