It began with a handshake between two friends at a little diner in Dedham.

Just two years later, the Hingham-based athletic footwear firm they dreamed up has established a reputation in its niche market, experienced healthy growth, and is about to launch an expansion into the apparel industry.

That’s no bull.

Or, more precisely, that’s NOBULL, the firm Marcus Wilson and Michael Schaeffer created and targeted at the functional fitness crowd. It’s a niche perhaps best known for CrossFit, an exercise regimen focused on combining the core movements of life into a workout aimed at improving health and fitness.

The name represents both the simplicity of the product and the company mentality, said Schaeffer, 48.

“There’s no rocket science technology here,’’ he said. “The name came from what we thought the product would look like. It’s a basic design, really well-made, without engineering gimmicks. This shoe isn’t going to make you run faster or jump higher; your hard work does that.’’

But it does, he said, provide the stability, support, and comfort needed to work out in a functional fitness exercise program.

The company’s founders didn’t come to their venture cold: They both know something about footwear design and marketing from many years at Reebok, the industry giant. Wilson, who’s in charge of NOBULL’s marketing operations and finances, was head of Reebok’s brand strategy from 2004 until 2007. Schaeffer, who oversees the finished product itself and the company website’s graphic design and content, was Reebok’s global creative director from 2005 until 2012.

After Wilson left Reebok, they’d meet often at the Dedham diner to catch up, as friends do. At first, both said, they had no intention of creating their own footwear company.

Initially their combined talent in marketing and website design led to the 2012 creation of Bold & Co., a marketing/design agency that serviced startup brands and some multibillion-dollar companies. But with their footwear experience and a vision for an under-served fitness category, they soon turned their diner talk toward starting — and self-funding — the venture that came to be NOBULL.

“NOBULL just organically happened,’’ said Schaeffer. “We are both passionate about sports and staying fit. It was a no-brainer to explore a fitness and training brand.’’

The footwear is partially made in this country. The upper portion is made from a rubber-compound military-grade material that is puncture-resistant, breathable, and flexible. It’s made in Minnesota, but the product is assembled in China.

New patterns not typical of a workout shoe, including flowers and argyle prints, come out every few months and have customers coming back for more with each release.

“We are so surprised by the passion our customers show,’’ said co-founder Wilson, who lives in Newton with his wife, Anisha, and two daughters. “It’s humbling ... and it’s amazing to see. People don’t own just one pair. They collect them, and they talk about it on social media.’’

One committed consumer even created a NOBULL Project Fanclub, which now claims 8,000 members.

The way the company releases products contributes to customers’ obsession.

First, in the United States at least, the company is exclusively an e-commerce venture, and designs and styles are one-time events.

“Once we release a design and the stock sells out, it’s gone,’’ said Wilson. “We don’t bring back the same patterns. It creates a sense of urgency and keeps the excitement and energy going.’’

With each new release, the production number approximately doubles, said Schaeffer. “Social media has been a key factor in our success,’’ said Wilson. “We couldn’t have done this five years ago.’’

Another part of their strategy: The designs and styles, which range in price from $99 to $299, are not specific to men or women — the floral patterns are as popular with men, just as women love the red and black lumberjack print, said Wilson. Right now, the company also offers hats and gym bags, and early this year it will launch an extensive apparel and accessory brand, to be manufactured in Lawrence.

The company does little else to advertise or market its products, but it does have four professional CrossFit athletes under contract to endorse the stuff. One of them, photogenic blonde Brooke Ence, a self-proclaimed professional exerciser and up-and-coming actress, is featured on the company website looking tough as she works out.

As with most startups, there have been bumps in the road. The very first shipment meant for a debut at a trade show was unexpectedly “not good and sloppy,’’ said Schaeffer, who lives in Norwell with his wife, Amy, and their three young sons. “It was not the quality and craftsmanship we hoped for and didn’t represent the company we wanted to be. We had to make a hard decision, but we made the right decision’’ — to reject them and eat the cost of the shipment.

Even as their firm seeks larger quarters and appears poised for growth, Wilson and Schaeffer say they plan to keep things simple. Their current space is furnished with plywood boxes they built for their first trade show, and the boxes will make the move to the new space.

“The simplicity keeps us grounded,’’ said Schaeffer.

Their eight employees share one large table that abuts a small workout station, which doubles as the location for the marketing videos and photo shoots they produce in-house. The working environment is very laid-back, with no set vacation or sick-day policy.

“We let them use their judgment,’’ said Schaeffer. “If they need a day off, they take it.

“It’s been a roller-coaster experience,’’ he said, “but it’s been a ton of fun, and we wouldn’t have it any other way.’’

Christie Coombs can be reached at mccoombs@comcast.net.