The Gym Rat: Ultimate Sandbag class

Sometimes, in this high-tech era of fitness apps, vibration platforms and electro-stimulation, it’s the simpler, more basic stuff that stands out most — like moving a bag of sand.

Doing deadlifts, squats and clean-and-presses with a 35-pound sandbag, as I did one morning in the Ultimate Sandbag class at the OmniSport Fitness gym in Tustin, is a lot harder than it looks. Unlike dumbbells and kettle bells, the rectangular sandbags are constantly changing shape, from awkward to more awkward. The sand shifts as you hoist the bag at varying speed and direction, forcing microsecond muscle balancing and rebalancing that builds killer all-body functional strength and stability. “I call it 360-degree training,” says OmniSport owner Josh Raphael, one of the country’s 36 certified master instructors of Dynamic Variable Resistance Training. You know how the paleo diet supposedly gets us back to our healthy caveman roots? Ultimate Sandbag is the paleo workout.

Omnisport Fitness and Performance, 500 El Camino Real, Tustin; omnisportfitness.com

Aura: Seven men and women, from newbies to old bags, spread out at this old-school neighborhood gym. As your heart rate rocks to Bon Jovi, Aerosmith, Guns N’ Roses, and AC/DC, all eyes stay fixated on the burly Raphael as he lays out the technique of each exercise and makes you do it right.

Effort: Serious. This is hard labor — prison-movie stuff. “Oh, God. When’s it over?” I moaned after five minutes. No rhythmical, aerobics-style endorphin high here, just heaving breaths, screaming muscles and dripping T-shirts. We rotated the multi-handled bags around our heads and shoulders, deadlifted them to the side while doing rear steps and side-step Good Mornings. We did bear-hug squats (imagine picking up a giant grocery bag). The complexity grew as we worked up to the highlight of the hour, a couple of super-heavy, minute-long walking carries. At the end, I threw down the bag as if I hated it. My classmate Lisa Deathereage, a toned 56-year-old Tustin local, told me she’d lost 75 pounds doing this and a boot camp three times a week.

Style: Having learned years ago not to push clients too hard too fast, Raphael starts with 15 minutes of bag-free, full-range-of-motion, strength-and-stretch warmups. A stickler for form, he throws exercises at you nonstop until the last 10 minutes, when he grants a few 15-second breaks. You will need them.

health@latimes.com