Members subscribed to the Training Pack get access to Dynamic Intervals.
Dynamic Intervals use your best times for each stroke to intelligently adjust the intervals on each set to you.
To use Dynamic Intervals, you must be a Premium Subscriber (or be on a free trial). Navigate to the Profile page, tap on the gear icon, then in Workout Settings and tap on Dynamic Interval Times. Input your best time for each stroke and distance. (It's ok to guess if you're not sure. Even vague guesses at your best time will help us shape the intervals to you.)
After you've inputted your times, all MySwimPro workouts (WOD, Training Plans, and Workout Library) will be adjusted using Dynamic Intervals.