Once the world’s largest sporting goods retailer, Sports Authority filed for Chapter 11 bankruptcy Wednesday and said it will close 140 stores, nearly a third of its locations, over the next three months.

Customers and others had long complained that Sports Authority’s shopping experience was drab and outdated. The company’s stores were more warehouses of athletic supplies than the updated locations of its competitors, namely Dick’s Sporting Goods, that offer an “immersive” experience.

“In retail, you can’t just leave all the stores alone forever,” said Paul Swinand, an analyst at the investment research firm Morningstar. “You have to constantly reevaluate your stores or else they get old. If you don’t see changes coming and you let that go for too long, you end up with tired stores and tired customers and brands that don’t want to give you their best product.”

In an open letter to customers, chief executive Michael Foss acknowledged the challenges of a changing retail environment. He said the bankrupcty process would allow the retailer to upgrade its in-store experience and enhance its website.

“This was a tough decision to make, but we believe it was a necessary step in our plan to make Sports Authority an even better partner for our customers,” Foss wrote.

Headquartered in Englewood, Colo., the privately held company employed 16,000 people and recorded $3.5 billion in sales last year, according to Forbes. Sports Authority disclosed $1 billion in liabilities in its petition and between $500 million and $1 billion in assets.

Sports Authority was purchased by Kmart in 1990 but spun off independently five years later. It merged with Gart Sports in 2003. After its $1.4 billion purchase by the private-equity firm Leonard Green & Partners in 2006, it ceased to be listed publicly.

After the deal, the new owners pledged to reinvest in the retailer’s locations, but then the Great Recession hit, and competitors gained ground.

In January, the company reported that it missed a $20 million debt payment.

“They haven’t been in a good position competitively for a while,” said Charles Lindsey, an associate professor of marketing at the State University of New York at Buffalo.

Swinand, the Morningstar analyst, agreed. He said fitness retailers have tended to weather competition from online outlets better than other businesses, in part because if shoppers want an item such as a baseball glove, they typically prefer to go to the store and try it on.

Sports retail is a convenience and experience-based business. Sports Authority just couldn’t keep up with its more nimble rivals.

“It sounds like Monday-morning quarterbacking,” he said, “but in my mind they had tired stores, and Dick’s just has better brands, better stores and a better shopping experience.”

Sports Authority is the latest of niche big-box retailers to file for bankruptcy protection or close. Circuit City filed for bankruptcy in 2008, and so did Borders in 2011. Both chains closed soon after. RadioShack filed for bankruptcy in 2015 and sharply reduced the number of stores.

Sports Authority has yet to identify the stores it would close. Foss sought to reassure customers that the terms of their gift cards, loyalty programs and credit cards should not change.

In 2011, Sports Authority bought the naming rights to the Denver Broncos’ stadium through 2035. It pays $6 million a year for those rights.

It’s unclear after bankruptcy proceedings whether the stadium, Sports Authority Field at Mile High, will continue to bear the company’s name.

An earlier version incorrectly identified Charles Lindsey as an associate professor of management. He is an associate professor of marketing. The story has been updated.