Man versus machines? In the realm of fitness at least man seems to be winning.
Despite a gym floor bulging with weight-lifting equipment, fitness experts said the only thing people need to push, pull and lift is the weight of their own body.
"If more people knew you could get a good physique using your body as a bar bell, they could take matters into their own hands," said Bret Contreras, author of "Bodyweight Strength Training Anatomy," a guide to bodyweight-only workouts aimed at everyone from the exercise-challenged to the personal trainer.
Known as "the Glute Guy," Arizona-based Contreras has been resistance training for 21 years. But in high school, he couldn't do a push-up.
"At 15 I was so skinny people used to make jokes," the 37-year old said. "I just got so tired of being made fun of I decided to take charge."
Often thought of as a stepping stone to weight training, bodyweight training can be a complete, whole body workout in itself, Contreras said.
Once the person masters the simpler version of a push-up, squat, or chin-up, a more advanced version can be tackled, often with a little help from the living room furniture.
"Find things in the environment: a table to get underneath, hold on to the sides of and then pull the body upward; a rafter for a pull-up," he said. "To work your glutes (buttocks muscles), all you need is a couch."
Contreras recommends the beginner start with 15 minutes a day and increase over time.
"It doesn't have to be intimidating," he said. "You could do a 20-minute workout three times a week and have an incredible physique, so long as you push hard and keep challenging yourself."
Bodyweight exercises return people to the way they move naturally, according to Lisa Wheeler, national creative manager of group fitness at Equinox, the upscale chain of fitness centers.
"We squat, lunge, crawl, reach," she said, adding that a bodyweight class at Equinox is called "Animal Flow" because its crab crawls, lunges and swings were inspired by the primal movement patterns of man and beast.
"Bodyweight training is great for mobility, stability and creating movement patterns," she said. "You want to build a strong foundation, be stable around the shoulders, hips and spine."
Because the load doesn't change, progression is achieved by changing the center of gravity of the exerciser or the complexity of the movement.
Another challenge, she said, is getting enough pull to match the push of most bodyweight exercises.
"Bodyweight training can make everything else better," she said. "Dancers, moms, we all live push-pull now."
Jessica Matthews, an exercise physiologist with the American Council on Exercise, said bodyweight training blends with the trend toward functional training, or training that mimics the way we move in everyday life, as opposed to the older bodybuilder model of targeting one muscle group at a time.
"Our body is one kinetic chain, everything moves together, so most everyday exercises will move multiple muscle groups," she said.
Matthews said not only can bodyweight training be done anytime, anywhere, it also works easily into popular interval training, circuit and boot camp workouts.
"Using bodyweight exercises allow more of a cardiovascular component because you can move rapidly from one exercise to the next," Matthews said.
So are machines a thing of the past?
"I think there's a place for everything," she said, "For some people a fixed path might be the way to go. It boils down to having proper joint stability and quality range of movement, then adding load. Form is imperative."