"Somewhere in the middle of that run we stopped and said, 'Hey, how do those toe socks feel?'" recalled Joaquin, now 33.
"It feels like I'm barefooted," said Randuz, 34.
Sitting around the campfire that night, the brothers - renaissance types who surf, play music and stage photo exhibits - could only talk toe socks.
"From that evening on," Joaquin said, "that was the rest of our lives."
Today, the brothers are founders of San Diego-based Injinji Footwear Inc., a toe-sock company that sells its product at 63 Recreational Equipment Inc. stores, hundreds of specialty running shops and to distributors in six countries.
The company is privately owned and the brothers will not give sales figures. Since a November 2001 Runner's World article endorsed their product, the brothers say they've doubled sales every year. Besides three partners, Injinji employs six people.
In 2005, Time magazine called the socks one of the year's most amazing inventions.
Suffice it to say the brothers have come a ways since 2000 when they'd run 5K and 10K races, and then, with racing bibs still pinned to their shirts, hustle off to peddle socks out of their 1971 Volkswagen van.
Randuz and Joaquin were raised in New Jersey. Their Honduran father was a longshoreman. Their Spanish mother, Vilma, raised the boys. It was Vilma who nurtured their creativity.
"She encouraged us to draw," Randuz said.
"Being from New Jersey, the West Coast always symbolized treasures, finding treasures," Randuz said. "Kind of like the Gold Coast."
They did piecemeal work to pay the bills. Randuz tended bars and waited tables. Joaquin sold Birkenstocks. They did freelance photography, shooting a model one day, and brochures the next. If a band needed a percussionist or drummer, they'd fill in. They formed their own band, Moceans, named after a New Jersey surf shop.
"We were always the salt and pepper for other projects," Joaquin said.
Until the toe socks. Originally, they thought the action-sports world would be their niche, but upon setting up a booth at the Action Sports Retail Show in 2000 they quickly realized it wasn't.
"Sixteen-year-olds breaking their arms jumping stairs (skateboarding) wasn't our demographic," Joaquin said.
At the expo they met Greg McMillan, a former Clif Bar representative who coaches runners, gave him a pair of the socks and McMillan loved them.
Eight years later, marathoners and ultramarathoners form the core of Injinji's clientele. Runners say the socks help prevent blisters and alleviate pain from growths on the foot. They also say the socks allow the toes to move individually for better gripping.
Marathon runner David Goggins won a pair of Injinjis at a 50-kilometer race last August and has worn them ever since.
"I thought they were phenomenal," Goggins said. "I stopped getting blisters, I'll tell you that."
"It feels like you're not wearing anything," said Mike Jackson, a manager at Movin Shoes in San Diego's Pacific Beach neighborhood. "You feel like you're barefooted."
Jackson estimates that Injinjis comprise 10% of the store's sock sales. He said runners, unaccustomed to feeling something around each toe, at first are "perplexed" by the socks.
"I'm 32," said Goggins. "Anytime you go 32 years wearing normal socks, then put something different on your foot, when each little toe has its own little sock, it's weird at first. But after wearing them a couple of times, it just feels good to have all your toes grabbing."
WHAT'S IN A NAME?
Why call the socks Injinji?
Randuz Romay said he had a chance, 10-minute meeting with a woman who was a musician. She was learning to play percussion instruments from a master African drummer. Randuz plays percussion instruments as well.
The master instructor told the woman that drummers like to achieve a certain level of performance he called injinji.
Said Randuz: "It's that pinnacle moment of a traditional drum circle where the dancers and the rhythm of the music become one. Like a trance or acrescendo. You're not thinking. You're in the moment."
AT THE BEGINNING
The socks, which are also sold in an everyday style, are not cheap. They sell for $12 to $16, twice as much as some athletic socks. Runners say they're worth it because they last significantly longer than others.
Joaquin remembers the first time he went to the original Movin Shoes in La Mesa, Calif., in late 2000. Randuz waited outside in the car. Joaquin pitched the sock and was rejected.
"Runners aren't going to wear that," said a salesman.
Joaquin lied to a friend who was working for the brothers, shipping boxes out of the basement of their home. Joaquin told him they'd won an account.
"I didn't have the heart," Joaquin said. "It would have devastated us all."
The next day he went to the Movin Shoes store. The owner liked the socks and was soon selling them on consignment.
"Randuz and I had a gullibility, a naivete back then," Joaquin said. "We thought we'd design this sock and it would be immediately embraced. ... It kind of helped that we were ignorant. We wouldn't take no for an answer. Now, honestly, knowing as much as I do now, I don't know if I'd do it again."
In the back of their Pacific Beach building the brothers store some of their toys. Eight surfboards, golf clubs, bikes, a practice putting green, a drum set.
Mocean, their band, used to practice twice a week. Once a month is the norm now.
Joaquin plans to get an Injinji logo tattoo when sock sales hit a specific number.
"A seven-figure number?" he's asked.
"It is a high number," he said. "It's up there."