What is the requirement for arm movement during a pi rotation?

The requirement for arm movement during a pi rotation is that it must be uninterrupted. This means that the arm movements should flow continuously and not be broken or halted while executing the rotation. Interrupted movements can detract from the aesthetic quality of the performance and may affect how the judges perceive the skater's proficiency and control during the rotation.

Fluid and uninterrupted arm movements enhance the overall visual appeal and demonstrate a skater's ability to maintain balance and composure throughout the maneuver. This requirement is essential for showcasing technical skill and artistry in synchro skating, where coordination and synchronization with teammates are key components of the routine.

The other options do not align with the established guidelines for arm movement in this context. For instance, having fixed arms would limit expression and flow, while positioning them below the shoulders or alternating positions might disrupt the continuity that is crucial for a graceful performance.