Pushups are one of the most effective overall bodyweight-only conditioning exercises. Doing them with the proper form is important to gaining the most benefit.
Its Pushup Time is a pushup counter that uses advanced algorithms to make sure that you are using proper form when doing pushups.
Just strap your device on your arm using one of the many iPhone armbands that are available and get to work.
Audible feedback is provided when you have reached the proper point in your descent.
Also see other apps: Sit Up Time and Jump Rope Time!