Sit-ups are one of the most effective exercises for your overall core strength. A strong core can help prevent back issues and who doesn't want a six-pack? Doing them with the proper form is important to gaining the most benefit.

Situp Time is a sit-up counter that uses advanced algorithms to make sure that you are using proper form when doing sit-ups.

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.

Pushup Time and Jump Rope Time also available.