I was glad to see Daily Arm Workout as the free app today as I definitely need to increase arm strength for the daily rigor of moderating an Internet forum!The app includes two workout sets and workouts can be 5 minutes, 7.5 minutes or 10 minutes. There is a video of each exercise, a timer and a description. Workouts can be paused, and if you exit the routine and come back, you can start with a specific exercise. You can also create your own custom workout.
I think it works best in portrait mode, at least at first; you can see the description of the exercise as well as the video, and the video size doesn't get that much larger in landscape mode.
You can set an MP3 to play before starting the app and have it play while you work out. A suggestion: "Take My Breathe Away" by Berlin, which will last for the whole five minute workout. ;-) Longer workouts? You're on your own!