iInterval app for iPhone and iPad

Interval training is basically exercise which consists of activity at high intensity for a period of time, followed by low intensity exercise for a period of time. These sets are repeated.
Interval training can supercharge your fitness, boost your metabolism, and burn off more extra fat than training at the same intensity level.
iInterval allows you to save an unlimited number of interval configurations. It notifies you 5 seconds prior to an intensity change via a “beep” sound.
Also, iInterval allows you to listen to your favorite music while running the app.