The ability to make a cardio work out with machines (elliptical, treadmill, rower, stair climber etc.) and set pace, heart rate, resistance, and elevation with time blocking. ie. 5min warm up at 50% heart rate at resistance 3 elevation 1, followed up with a 2 min 70% heart rate at resistance 6 elevation 3, next up a 30sec sprint at 90% heart rate at resistance 9 and elevation 3, so on and so forth.