Getting in shape can sometimes require reverting to our primal nature.

That’s trainer Matt Pack’s idea behind his new workout studio, Primal Fit, in Miami Shores. The goal is functional fitness. “I want the quality strength that we build in Primal Fit to carry into real life — to pick up groceries, work in the yard, carry your children, ride bikes and be active,” Pack says.

Thus, the movements mimic what we do in our daily routines. In small classes of no more than eight people, under the observation of two trainers, students are paired on large mats to run through an hour’s worth of exercises. Some of these use props like club bells that resemble miniature baseball bats but are made of metal and weighted and swung in a wide fluid arc to work the core or shifted back and forth behind the head to develop the triceps and biceps. Sliding foot pads on the floor are used to develop legs and the abdominals. Other movements feature pulling, pushing, climbing, rotating and even crawling, as if under a fence, via squats, bends and lunges using one’s own body weight.

“That’s why I call it Primal,” Pack says. “These are movements our bodies are designed to do so we’re bringing it back. We’re a society that sits way too much. At Primal Fit we keep you standing and moving and keep it simple.”

Earlier this month Primal Fit incorporated a nod toward technology. Students are outfitted with My Zone belts that wrap around the body and have built-in hard drives that can store up to 16 hours of information. As you exercise, the belt beams stats onto a wall display noting heart rate, energy consumption and calories burned. The system assigns “energy points” based on how high you can get your heart rate. The same information is uploaded to a computer and emailed home after every session so individual progress can be charted and goals set. Classmates can compete to best one another but they can also use the belts at home and Pack can analyze the data to see what a student needs to do to continue progressing.

“I love comparing in the email to the previous class,” says lawyer/lobbyist Darren Patz, 38. “It’s certainly motivating. If you don’t have data you can’t measure performance.”

Stephanie Traband, 39, a litigator, and Kathy Sullivan, 46, a Bay Harbor Islands police officer, also measure the results on how they feel.

“I came to a point in my life where I need to make major changes,” says Traband, a mother of two, citing the stress of work with a lack of exercise. “I was literally sick every three weeks. I believed I was going to stroke out at my desk.”

Traband says she has lost 50 pounds in a year’s time from three Primal sessions weekly and has better mental clarity. “I lost the weight slowly, consistently, and steadily saw results and so I’m not joking when I say I believe Matt saved my life.”

Sullivan was a triathlete but hit burnout after one too many Iron Mans. “I have two kids, took some time off, and got pudgy,” she says. “I saw results in 30 days I haven’t seen in 13 years of doing triathlons.”

The new computerized belt, however, is another prime motivator.

“The next time you go to Starbucks you’ll think twice about that cupcake,” Sullivan says. “You just burned 900 calories and you can put it all back on with that cupcake.”