2. Workout Trainer (Free; Android, IOS)

Skimble's Workout Trainer (Android, iOS) offers users thousands of free workouts complete with timed step-by-step audio and video instructions to help you get into shape. Whether you're looking to sculpt six pack abs or improve your conditioning for that next race, Workout Trainer has a routine just for you. In addition to the built-in workouts, users can access the app's library to build their own custom routines and share them online, as well as try out routines shared by the community. A premium subscription unlocks more features such as HD workout videos, more exercise routines, as well as removing ads.