Ironman is full of familiar faces: a local accountant, a neighbor, the stay-at-home mom from church, a local YMCA instructor.
There are professionals whose lives are dedicated to the sport, but Ironman primarily consists of age-groupers, the term used for the non-professional athletes who make up the majority of the race. They balance careers with families and hours of training, a sacrifice not just for the athletes but for their families and friends.
Some just want to prove to themselves they can finish the race, others dream of a high finish at this weekend's world championships, hoping to be among the best triathletes in the world.
Marsha Goldberg had given up.
Her father unexpectedly died in March and she no longer wanted to train or deal with the pressure that comes with Ironman.
POLL: Do you plan to watch this weekend's Ironman?
She was broken. It was not supposed to happen. Her dad, Robert Skinner, had been sick but he was supposed to be OK. Then, his heart stopped.
He had once traveled from his Georgia home to Chattanooga to watch his daughter compete in her first Ironman in 2015. She had spent months getting her body in top condition for both Ironman 70.3 Chattanooga in May and Ironman Chattanooga this month, but with his death Ironman no longer seemed important.
"We weren't ready for him to go," Goldberg said. "That affected me bad. I lost all interest in training. I couldn't even get up on the bike or anything. I couldn't."
Elizabeth Baker, a training partner who first got Goldberg interested in Ironman, called and told her she could not quit; it would not have been what her father wanted.
"You have to do this for your dad," Baker told her. "You have to push hard for him, because he would be so upset if he knew you gave up on your dream." She was right and Goldberg knew it.
She got her father's name tattooed on her forearm where she can see it while on the bike and training resumed.
With the help of trainer Robyn Wilham, Goldberg said, she quickly got back into racing condition for May's Ironman 70.3. She finished in five hours and 22 minutes — far better than her expectations.
Goldberg, a local fitness instructor, then began preparing for the full event. It involved early morning workouts and sacrifice, she said, but more than anything, it involved a supportive family.
"I could not do anything I do without my husband, without his absolute complete support and dedication to my goal," she said. "He's my rock."
Goldberg starts her morning at 4 a.m. with a training ride or run. Her husband, Dan, a banker at Pinnacle, brings her breakfast once he wakes up. Then he gets their two children, 9-year-old Brody and 11-year-old Reese, ready for school, packs their lunches and gets them on the bus.
"If it wasn't for him I couldn't have done this," she said.
She finishes her morning workout, teaches her fitness classes and finishes with a swim or other workout before picking up the kids from school and shuttling them to activities.
Goldberg teaches spin, barre and other classes between her two jobs at the Downtown YMCA and Balanced Studio on Signal Mountain.
She is a hit among her students, who speak highly of her character, her intensity and, most of all, her kindness.
"The thing you know about Marsha is you know it's going to be intense, but you also know she's working as hard as we are," said Forrest Simmons, one of the men in her Wednesday spin class at the YMCA. "That's the thing that I love about the class. You know she's working as hard, if not harder, than anyone else in there, and it's really motivational.
"She's an inspiration knowing that she's doing the Ironman, just seeing how fit she is. The other thing is that before and after the class, she'll talk to you, and she's one of the nicest people you'll ever know. She's very encouraging."
While the classes certainly help with her fitness, Ironman requires more specialized training that can't come in her class settings, she said. So like many age-groupers, she trains, goes to work, gets off and trains some more.
Along the way, there's been a missed birthday party, time away from her children and added pressure on her husband during the training.
This weekend's race is going to be it for a while for Goldberg. She's not completely calling it quits — she may race again in the future and plans to continue to stay active in other events — but it will be a while before Goldberg is again seen competing in such a grueling race.