If someone offered to pay you for doing exercise would you do it? What if you had to pay someone if you failed to do the exercise you promised? That's the idea behind a new app that taps into exercise app and website Runkeeper to reward or penalise you if you exercise.

In a move that could change the way you exercise in the future, RunKeeper has announced a partnership with GymPact, to help you overcome your excuses by putting real money on the line as a motivator.

"By using RunKeeper + GymPact together, if you don’t stick with the 'pact' you commit to around your fitness goals, you have to pay.  And if you stick to the 'pact', you get paid!  Now THAT is motivation," say the developers behind the idea.

RunKeeper users will be able to count specific runs tracked by GPS. Runs will have to be over a minimum of 800m in distance, or 30 minutes of activity with a pace above 3.2km per hour to qualify.

Users who fail to meet the pact they have made at the beginning of the week will be charged $5 per exercise they miss. Those who have meet their suggested quota will be rewarded.

"Every Sunday night, we will take attendance and charge the credit cards of people who did not meet their pact that week.  We then pool this amount and divide it among those who met their pact, based on how many times they committed," confirms the site. "For example, someone with a five-day pact will get five portions of the pool on Sunday night. Your stakes do not determine your rewards; only the days committed do!"

Exercise fans keen to go over their agreed quota will also be rewarded.

"Going extra days above your Pact is awesome, but you only earn for the number of days committed.  Users earn on average $0.50-1.00 per day committed."

At the moment the app only works with the iPhone, and iPod and iPad, but the company is hoping to add a HTML 5 version to allow Windows Phone and Android smartphone users to benefit too.

According to the GymPact, People who use the service make 86 per cent of the workouts they commit to.