Early in the morning, while most humans and their pets are still in bed, a few brave souls start the day with boot camp.
They are not just pounding the pavement with two legs, however, but with many more, three or four to be exact.
They are taking part in Thank Dog! Bootcamp, a training program for dogs and their owners that has expanded to locations nationwide.
"We have aggressive dogs. We have overweight dogs. We have little dogs. We have dogs with three legs," Jill Bowers, the program's co-founder, told ABC News.
The program, now in cities from Boston to Chicago to Los Angeles, provides a one-of-a-kind fitness training program that allows dogs and their owners to work out alongside one another for an hour at a time.
"It's sort of killing two birds with one stone," Bowers said. "No matter what, you need exercise. A dog needs exercise and obedience training so they come every day."
The idea for Thank Dog! Bootcamp was born in 2007 after Bowers began working out at Barry's Bootcamp, a California-based workout program popular with celebrities like Kim Kardashian. Bowers then had the idea to partner the company she already owned, Thank Dog! Training, Southern California's leading dog obedience training company, with a Barry's-like boot camp regime for owners and dogs alike.
"When people sign up for boot camp, they don't leave because it becomes more of a lifestyle than anything," Bowers said.
Bowers and her business partner at the time got the idea off the ground and, in 2009, Bowers partnered with Noelle Blessey, a personal trainer and boot camp instructor, to bring the boot camp portion of obedience training to life.
Blessey took " Good Morning America" special correspondent Cameron Mathison through the paces of a typical 60-minute Thank Dog! class, which range in price from $10 as part of a package to $25 for a single class.
Together Mathison and his workout partner, a dog named Quinn, stretched, sprinted, flexed and panted their way through the hour long class combining cardiovascular training, obedience training for the dogs, and strength training.
"The hour goes by so fast. You don't even know it's been an hour," said another boot camp attendee. "It's great to be outside in the park rather than in the gym. Your dog kind of makes you get up in the morning and go."
For those dog-less individuals longing to work out with a dog, Thank Dog! has a solution: they provide dogs that attendees can borrow for the duration of the hour-long class. And for those who don’t live within driving distance of a Thank Dog! Bootcamp hub city, Thank Dog has developed a doggie boot camp app, showing how owners can work out with their dogs in the comfort of their own home or a nearby park.
After a tough boot camp session, when dogs and their owners want to unwind, they can turn to dog yoga classes, another trend in the exercise-with-your pet phenomenon.
Like doggie bootcamps, doggie yoga classes, also known as doga, have now popped up across the country.
The Bidawee Animal Shelter in New York City offers doga events for "pet parents interested in trying this new fitness routine and helping their dogs maintain or achieve a healthy weight," according to its website.
Among other things, Doga is credited with helping calm nervous dogs' nerves and with helping to improve a dog's digestive tract.
"It makes so much sense to do yoga with your dog since dogs already routinely practice yoga," Amy Tobin, a doga instructor, told ABC News. "They [dogs] are very much of the moment, they live in the moment."