Read this: Chopin's polonaises show a marked advance on those of his Polish predecessors in the form (who included his teachers Zywny and Elsner). As with the traditional polonaise, Chopin's works are in triple time and typically display a martial rhythm in their melodies, accompaniments and cadences. Unlike most of their precursors, they also require a formidable playing technique.

Chopin's polonaises needed what kind of playing technique?
What is the answer? (If it cannot be answered, return "unanswerable")
formidable