In the age of pop-ups and food trucks, it was only a matter of time before the fitness world popped on the bandwagon.

All aboard Dryft, a San Francisco–based mobile gym, equipped with 36 workout stations, that's rolling up to some of the city's most scenic locales—Marina Green on Saturdays, Ocean Beach on Sundays—for Insta-worthy sweat sessions.

There are few places we'd rather spend a Sunday than at Ocean Beach, and that's where we headed for our noon class with Dryft, a big, blue, solar-powered semi truck that, transformers-style, opens up with a kind of terrace to let in the ocean breeze for open-air workouts once parked (you can check out a video of its nifty setup online). And like any chichi fitness studio in SF, there are electronic lockers and a boutique where you can purchase sports drinks and the like.

Dryft's philosophy of fitness is simple: Work out effectively, strategically, and in under 50 minutes. "We want this class to feel like you got 90 minutes worth in an hour setting," said our class' co-instructor Landan Laurusaitis, as we snaked through a sea of rowing machines and strength training stations, backdropped by rolling waves. "We rotate between high-intensity rowing to focused strength training, so that you feel that you've hit every muscle in your body when you leave."

When the hour hand struck 12, we collected our dumbbells, saddled our benches, and we were off to the races.

A series of jumping jacks, stretches, and yoga-inspired poses limbered us up for the various bootcamp-style movements to come: burpees, fast high-knees, dumbbell bench presses, weighted lunges, and a litany of core-activating exercises. Then, a quick 30-second break before cozying up to our rowing stations.

Bass-thumping, adrenaline-inducing EDM set the soundtrack, and for the next 15 minutes, we rowed like no one was watching, ebbing and flowing between bursts of high intensity, with abdominal- and bicep-targeting movements, and the odd in-motion break. We managed to paddle 2,500 meters, a class best (and hard won). We were also encouraged to keep increasing the resistance throughout the rowing portion, maxing out our device; Dryft head trainer Kym "Nonstop" bounced around the room, making sure we were testing our limits.

For the remaining 30 minutes, it was rinse and repeat: another strength training sesh followed by 10 more minutes of rowing, this time at a more even pace. Our Dryft class closed with a bit of mindful stretching and mental centering.

As Laurasaitis assured us we had earned our dinner over this sweaty lunch hour, we looked out to the sunny Pacific Ocean for validation—and it delivered.

// Dryft classes start at $35 per class, with bundle deals also available. Towels and water filling station are provided. Pop-up classes are at 1 Marina Green Dr. (Marina) on Saturdays and 962 Great Highway (Golden Gate Park) on Sundays, letsdryft.com.