Some joggers weren't joking when they said they were going out for a "brief run."
In briefs, boxers, bras and bloomers, they ran three-quarters of a mile in a Valentine's Day-related charity event benefiting sick children.
Saturday's annual Cupid's Undie Run featured 1,000 people in their underwear and little else, except for maybe some body-painted hearts, angels and Cupid's arrows on their chests. Participants, some of whom shaved hearts into their chest hair, ran through the streets near the city's sports stadiums.
Previous years' events have taken place despite snow, but weather for this year's was sunny with temperatures approaching 70 degrees, prompting runners in their scanty panties to chirp, "Sun's out! Buns out!"
Sisters Melissa Tamimi, in gray panties and a matching sports bra, and Sofia Tamimi, in black panties and a gray lacy bra, had no problem mentioning their unmentionables.
"I'm about as comfortable as you could be running in underwear," Melissa Tamimi said.
Similar events took place in other cities, including St. Louis, Miami, Pittsburgh and Cleveland. Money was raised for the Children's Tumor Foundation to help research neurofibromatosis, a genetic disorder that causes tumors in the nervous system. The incurable disorder can cause physical deformities, blindness, deafness and chronic pain, usually in adolescents.
Runner Jeff Eckert, who's 30 years old, said he was diagnosed with neurofibromatosis, also called NF, when he was 5. He said he was participating in the Undie Run wearing Superman boxer shorts to help raise money and awareness.
Philadelphia race director Dan Frenia, whose wife and 12-year-old son have been diagnosed with NF, said this year's race raised hundreds of thousands of dollars and the national events have raised about $20 million over the last few years. He said he hoped to grow the Philadelphia event from 1,000 people to 3,000 or more and spread the word about NF so a cure can be found.
"This is our passion in life," he said. "This isn't just a one-day event for us."
Cupid's Undie Run is a fun run, not a race, organizers said, so there was no declared winner other than the Children's Tumor Foundation.
Friends Ellie Russo and Kendra Scherer ran among the 53 members of a team called Hope for Ella, which was named in honor of a 10-year-old girl with NF and raised the most money on Saturday, $26,810. They wore red bras and matching cheeky boy shorts with a message on the buttocks: "I take my pants off for charity."
In total, the event brought in $207,000 for charity, organizers said.