But despite the proven benefits of an active lifestyle, less than half of U.S. adults meet the current recommended guideline of 10,000 steps per day. Knowing this, the question becomes: How can employers motivate their workforce to be more active?

Many employers offer incentives, such as rewarding employees who meet prescribed activity goals. Walk a certain number of steps with a wearable tracking device, get a reward, such as cash, a gift certificate, or discounted health insurance premiums.

So, why are so many employees still opting not to participate? It turns out that boosting fitness participation may have less to do with the rewards, and more to do with the goals employees must reach to obtain those rewards. Some incentive goals, if perceived as too difficult, may immobilize employees rather than inspire them to action.

To better understand how goal difficulty — or perceptions thereof — might impact employee participation in a physical activity program, in 2011, American Specialty Health (ASH) embarked on a retrospective study to compare two different goal structures within the company's own wellness program.

ASH has long had a wellness program administered by its Healthyroads subsidiary, and this wellness program has included an incentive structure that incorporates physical activity tracked monthly and quarterly via step tracking. A change in the incentive structure between 2011 and 2012 provided an opportunity to compare how well different goal structures worked.

Within this study, participation and achievement outcome measurements were compared for participating employees over these two years. In addition, a subset of the same group of 320 Healthyroads employees was studied over the two-year period in 2011 and 2012.

Here are the two goal structures the study compared:

• In 2011, the organization used a single-tier incentive design that awarded $100 to employees who took at least 500,000 steps per quarter.

• In 2012, the model was changed to a three-tier incentive design for employees, as follows:

  • 100 for 400,000 steps per quarter;

  • $125 for 650,000 steps per quarter, or;

  • $150 for 900,000 steps per quarter.

The study, published in the journal Population Health Management, found that the three-tier incentive design significantly boosted participation in the company's step program compared to the single-tier design used the previous year. Here are the key findings:

• Improved participation: The number of employees who participated in the step program increased from 64.7 percent in 2011 to 72 percent in 2012.

• Increased quarterly incentive goal attainment: The number of employees who reached at least one quarterly incentive grew from 36.3 percent in 2011 to 51.4 percent in 2012.

• Higher daily steps by the same individuals: The average number of steps per day taken by the same employees increased by 27 percent (i.e. 2817 to 3573 steps per day) between 2011 and 2012.

These findings suggest that offering employees additional options for setting fitness goals — including ones that feel easier to reach — may drive greater fitness participation.

Having more choices may have helped empower the same employees, with presumably the same physical limitations, strengths, and fitness levels, to strive for a goal they may have felt too discouraged to attempt the year before.

The idea is based on common sense. But it also reflects a basic theory of behavioral economics: Offer people a choice of two goods of the same quality or value, and most, logically, will buy the good with the lower price.

In the same way, offer employees the same $100 reward, but with an easier way of attaining it, and more employees will strive for that reward. Under the 2011 incentive plan, an individual earned one cent for every 50 steps.

But the 2012 design allowed that individual to earn one cent for only 40 steps, which made achieving the first tier reward 20 percent easier and increased the value of each step taken, compared to 2011.

A multi-tier incentive design offers something for everyone, rather than a one-size-fits-all approach. Multiple tiers allow you to meet your employees where they are with their varying, individual fitness levels. The bottom tier may help motivate less active employees to try for the first incentive, while the middle and top tiers provide a challenge to more active employees.

Finally, a multi-tier incentive design may help build self-efficacy — the belief held by employees that they really can make health-related changes. By replacing a single-tier step goal with a three-tier step goal, you allow more employees to experience success. That, in turn, may give participants the confidence to try for the next tier.

The study demonstrates how even small tweaks made to a wellness incentive program can help garner big gains in fitness outcomes for your employees.