"It's like a marathon here at the store," joked manager Lerma Jean Nakashima. "And they're still here. We see them walking around, some in a lot of pain."

The Running Room is one of many local businesses that benefit from the annual event, which pumped $86.8 million into the state's economy last year. It's the world's sixth-largest marathon and the nation's third-largest race.

Business was up 20 percent at Island Triathlon & Bike on Kapahulu Avenue during marathon week, said owner Frank Smith.

"It's a trickle-down thing," he said. "The whole economy has picked up."

While the Honolulu Marathon generates a nice chunk of his annual sales, the Honolulu Century Ride in September was the shop's biggest event. This year the 23-year-old bike race drew a record 1,500 cyclists from Japan and an estimated $2.2 million in visitor spending.

"They just mobbed the store," said Smith, whose 20-year-old shop is well-known in Japan. "It was great!"

The marathon boasted 25,671 registered runners this year, with about 80 percent, or 20,639 participants, from outside the state. Of the total participants, about 60 percent, or 15,723, came from Japan, where the event's title sponsor, Japan Airlines, has its headquarters. (JAL also sponsored the Honolulu Century Ride.)

An official estimate of the economic impact of this year's marathon won't be available for a couple of months.

But clearly the large influx of Japanese visitors in early December — which would otherwise be a slow week for tourism — was a boost for Waikiki. Hotels were filled, restaurants packed, stores in Waikiki busy as ever.

"We see a sharp increase over the (marathon) weekend," said Joseph Toy, president of Hospitality Advisors LLC, which tracks state hotel occupancy. "Hotels start filling up beginning Thursday and Friday, then starts tapering off after Sunday."

Hotels in December run about 60 percent occupied. But the marathon pushes occupancy in Waikiki hotels to 90 percent and higher, Toy said.

"To essentially fill up the town for a weekend is a tremendous bonus to the industry and to the community," said David Carey, chief executive officer of Outrigger Enterprises Inc., a sponsor of the marathon. "It felt like there was a broader base of customers this year compared to last. People seemed to have an awful lot of fun this year."

While the tourism industry got a boost this month, so did local small businesses that worked on every aspect of the marathon, from printing brochures to putting up tents to providing sponges and paper cups.

Peterson Sign Co., a division of Sun Industries Inc., has been providing custom signs for the Honolulu Marathon on-and-off for about 20 years.

Sporting events in general make up about 20 percent of the company's annual sales, said sales manager Bob Peterson, whose father started the business in 1968. The Honolulu Marathon is one of its smaller events. The NFL Pro Bowl is its largest job, accounting for 5 percent — or about $60,000 — of its annual sales.

But for its parent company, Sun Industries, which specializes in traffic control and safety, the marathon is a massive project.

"We start planning in the middle of the year for it," said Joe Aguon, general manager for roadway safety services and rentals. "Our whole warehouse is full before the marathon, then emptied the day of the marathon, then full again that night. It's massive."

For the past five years, the company has provided cones, personnel, barricades and other equipment for the marathon. It also services other sporting events, such as the Ironman Triathlon World Championship, the Sony Open and the NFL Pro Bowl.

The Honolulu Marathon accounts for about 15 percent of the company's December sales, Aguon said.

"It's a big impact for us," he said.

For other businesses, the marathon is their main source of revenue.

Consider the Brian Clarke School of Running, which charges $225 per person for its marathon clinic.

"It's a big, big part of my business," Clarke said.

This year 65 people enrolled in his marathon training program, with 46 finishing the race on Sunday. Clarke likes to keep his classes small — no more than 75 runners — while offering other training programs for local triathlons and other running events.

"Most people who do my training program need the discipline," Clarke said. "They wouldn't run the marathon otherwise. ... They feel they need the structure and a group to meet and help motivate them."

He has found that people who enroll in his marathon program will sign up — and pay for — another one with him. That, in turn, grows his business.

"This is a major source of income for me," he said.