In theory, what is the proper movement pattern for the legs while running?

The correct movement pattern for the legs while running is characterized as "in a cycle." This refers to the natural motion of the legs as they propel the body forward. Each leg goes through a cyclical pattern of movements that includes lifting, driving forward, extending, and repeating. This is essential for maintaining rhythm and efficiency in running. The cyclic motion not only helps in effective propulsion but also aids in balance and coordination.

When considering the other options, moving backward does not apply to running, as forward motion is the key component. A straight line suggests a lack of the necessary forward momentum and may imply rigidity, which is not functional in running form. Side-to-side movement can lead to instability and is not how the legs should operate in a running gait. Therefore, recognizing the cyclical movement pattern is crucial for effective running technique.