Krzysztof is correct, we do not prescribe cadence in the workouts. However, we strongly recommend a cadence of 90rpm for any given intensity, at least as the terrain and gears allow for it.
Professional cyclists are dialed in to 90rpm regardless of the terrain or speed, and ensure their gearing allows for that high cadence even in hills. See Lucía, A.; Hoyos, J. & Chicarro, J. L. (August 2001). “Preferred pedaling cadence in professional cycling”. Medicine & Science in Sports & Exercise. 33 (8): 1361–1366.
David