01/05/2012 08:37 am ET Updated Dec 06, 2017

GymPact: Skipped The Gym Today? That Will Be $5

What if you lost $5 every time you missed the gym? All those happy hours and late night movie marathons that normally separate you from your newly affirmed fitness routine would add up to one expensive couch potato habit.

That's the premise of GymPact, a new smartphone app that forces users to show up or pay up: users make a 'pact' with the service to go to the gym a set number of days per week. For each day that a user does not show up on an appointed day, the app debits $5 from his account.

GymPact was created by two recent Harvard graduates who took their behavioral economics class to heart: "Behavioral economics show that if you tie cash incentives to things that are concrete and easy to achieve like getting to the gym, it's very effective," co-founder Yifan Zhang told the New York Times. "People don't like losing money and it’s one of the strongest motivators, much more than winning money."

But others are skeptical of a business model that may not be sustainable in the long term: the app makes money when its customers do poorly. Wrote Matt Yglesias at Slate:

The problem with GymPact is that the more successful it is, the less revenue it generates, and the more revenue it generates, the more customers will despise it. If GymPact really works, and you go to the gym more to avoid losing money, then there won't be any revenue or any way to fund rewards.

GymPact isn't the first app to ask fitness newbies to put their money where their mouth is: Health Rally, which recently won $400,000 in seed funding, has a similar service, although their program prompts users to select their own "rally team" to help motivate them with both notes of encouragement or monetary incentives. In other words -- it's mostly carrot, little stick and all among a private network.

For more, Newsy has the story: