Roberts had been teaching fitness classes using inflatable exercise balls for about seven years at the time, and he thought his adult clients might get even more out of themand have more funif the balls had handles.
"As adults, we tend to not do what we should, which is play like children," said Roberts, 49.
So he invented a harness that fits around the balls, making them more stable and useful. The harnesses sell for $59.97 each.
Since creating Bounderball in 1999, Roberts has invested about $300,000 on manufacturing and marketing his innovation. He incorporated the company in 2003 and began aggressively promoting the product about a year ago.
This year, he expects to bring in about $450,000 selling the harness and Duraball Pro balls through his Web site, www.bounderball.com.
Despite his progress Roberts continues to practice as a chiropractor to support his rather expensive "hobby." Roberts, who has taught ball classes about 16 years, also developed 150 exercises using the Bounderball.
His original idea of a bouncy ball for adults has evolved.
"Adults break more easily than children," Roberts said, so the harnesses include a warning label advising adventurous users to not bounce on the ball after all.
Instead, the handle adds stability for seniors and physical therapy patients who may want the benefit of working with a ball but don't feel up to chancing the risk of rolling right off one.
It also provides athletes a more ergonomic way to exercise.
"How you train is how you perform," Roberts said.
Standard training involves working out in a slow, linear mannerlifting weights, for examplebut athletes actually use fast, rotational movements when they are competing, Roberts said.
By combining the Bounderball harness with the elastic bands often used in resistance training, he found athletes could move more quickly, bouncing the ball off a wall for a fast-paced core workout. The Bounderball harness doesn't come with tubing, but has a place to attach it.
Roberts believes in exercise balls so much that he doesn't accept patients unless they buy one, though he said he doesn't push his own product on his clients.
In addition to selling the harnesses on his Web site, he has promoted the product by introducing it to fitness trainers and physical therapists in central Indiana.
Velocity Sports Performance has been using Bounderball about 18 months. Sports Performance Director Chris Powell said trainers use it to keep athletes balanced and as an alternative to the medicine ball throw.
Powell said they still use the medicine ball to vary athletes' workouts, but Bounderball essentially does the same work without putting weight on athletes' spines. Because the exercise ball is lighter than medicine balls, which can weigh anywhere from 2 to 22 pounds, athletes can isolate their core muscles but save their spines from carrying the extra weight.
"[Bounderball] helps them rotate with a lot more body control," Powell said.
Powell just used the product with a 23-year-old professional pitcher and children as young as 12.
Velocity is a national franchise with operations in 27 states, but the Carmel location is the only one using Bounderball. Powell is working to change that by introducing it to other sites.
Roberts fully believes in his product, and that faith has helped him in his journey as a self-funded inventor. Like many of his peers, he has been approached about licensing his creation to another company that would manufacture, sell and market it. Roberts isn't interested.
Larry O'Cull, founder of product-development firm Priio, has seen (and created) a lot of new products in his 13 years in the business. Although he doesn't advocate one way or the other, O'Cull cautions that keeping control of a product could cost an inventor the chance to keep creating.
"I think the licensing method in a lot of cases, it's underrated." O'Cull said. "A lot of people get an idea, and they think they have to make it big. [Licensing] is more secure."
Plus, licensing out to a large company takes the stress out of marketing, as a brand name is already attached to the product. And getting a product into big chain stores is incredibly difficult without the force of that brand name.
Even so, O'Cull said there are still plenty of opportunities for stand-alone inventors, too. He said Bounderball's Web site is a good way for Roberts to get Bounderball out on the market, especially since the product line is limited. He also advises inventors like Roberts to have a sound business plan and realize that marketing can cost much more than actually creating the product.
Inventing and marketing his product has been a long journey for Roberts. He went to a local venture capital club for funding early on, but said members were mostly interested in biotechnology at the time. They did offer advice, though.
If he had it to do over again, Roberts would try to start with more money and begin promoting his product sooner. He advertises Bounderball in fitness and physical therapy magazines and gets most sales through therapists' recommendations.
Roberts tried to manufacture locally, but the cost was prohibitive, so he went to China. After a second round of manufacturing, Roberts said, he's happy with the product.
Safety is a priority. Bounderball is made of a thick material and sewn with the same stitching used in seat belts.