It is preferable to use clipless pedals for this workout
Having mastered the one-legger drill, it's time to move on to a new exercise.
You will now add one minute of high-cadence training to your sets. This high-intensity workout will cause a net increase in your heart rate (15 to 25 beats), but that's completely normal.
However, this is not a maximal intensity workout. You should stay focused on your cadence instead of your heart rate monitor.