Say you're really determined to start going to the gym. So determined, in fact, that you're willing to follow oft-repeated expert advice and bribe yourself.

"If I go three times a week for the whole month, I'll buy myself that new TV/ fabulous handbag/ weekend away I've been craving," you might tell yourself. When it comes to motivation, that should do it, right?

Not according to fun recent research. The study, led by Mitesh Patel, a doctor and MBA at the University of Pennsylvania who specializes in healthcare management, investigated how financial incentives can best be deployed to encourage healthy behavior. He found the same incentives had wildly different effects on people's willingness to move more depending on how they were presented.

We fear loss more than we crave rewards.

To figure out how best to bribe ourselves to get healthy, Patel's team tasked 281 participants with reaching a goal of 7,000 steps a day for half a year. Each participant was assigned to one of four groups -- the control group got no incentive at all, members of a second group were given $1.40 for each day they made the goal (that's $42 a month), a third group was told they would receive one entry in a lottery to win that amount for each day they hit their target, and a final bunch were handed the $42 at the start of the month and told that $1.40 would be taken away for every day they failed to hit 7,000 steps.

Who walked the most? Not those who were given a reward for each successful day -- they walked no more than the control group. But fear of loss, apparently, is a much stronger motivator. "Participants who risked losing the reward they'd already been given (the loss-incentive group) achieved the goal 45 percent of the time, amounting to an almost 50 percent increase over the control group," reports the research release. That's double the motivation from a simple reframing of the same financial incentive!

What's the takeaway if you're an individual hoping to finally motivate yourself to start that fitness regime? Forget promising yourself that new flat-screen at the end of a month or year of being good. Instead, buy it and hand it to a close friend along with the receipt. Tell your buddy that should you make your goal, he or she can hand over the TV. If not, back to the store it goes. That, science says, is likely to double your motivation to actually hit the gym. (If your friend occasionally sends you taunting photos of the box, I doubt that would hurt either.)

A note for employers.

It's a fun conclusion for those looking to finally smash their stubborn resistance to forming healthy habits, but the research team also notes the findings have important implications for employers. If you want your wellness program dollars to stretch as far as possible, you need to pay attention to how you structure your incentives.

"Most workplace wellness programs typically offer the reward after the goal is achieved. Our findings demonstrate that the potential of losing a reward is a more powerful motivator," commented Dr. Kevin Volpp, who participated in the research.