What is a defining feature of Level 4 in difficulty groups for linear and rotating elements?

The defining feature of Level 4 in difficulty groups for linear and rotating elements is that it must consist of a choreographic series. This requirement emphasizes the importance of incorporating artistic and technical complexity into the performance, as well as ensuring that the elements are seamlessly connected within a cohesive routine. A choreographic series allows for the display of creativity and skill in synchronization, which are critical components in higher-level scoring in synchro skating.

By requiring a choreographic series, the evaluation criteria reflect an appreciation for not just the execution of elements but also how they are interwoven with artistic expression. The presence of a choreographic series signifies a higher level of performance because it demonstrates the team's ability to create a visually engaging and harmonious routine that maintains synchronization throughout, thereby meeting the advanced standards necessary for Level 4.