DeLoyce Alcorn is 92 years old — and pressing nearly four times that in weight at the gym.

On a recent Wednesday afternoon, Alcorn — dressed in a T-Shirt that read “Be Strong. Be Resilient. Be You.” — slid into the leg press machine, which was set at a whopping 312 pounds. He gripped the handlebars, closed his eyes and “got zen,” as he says. Then he pressed his legs forward very slowly.

“Slower, slower, smoooooth ...” urged his trainer, standing by his side.

The retired aerospace engineer, who lives in Sierra Madre, California, did about four reps before his teeth clenched, his legs trembled and he let out short puffs of air through pursed lips. The exercise was just one minute and thirty-three seconds. Afterward, Alcorn sprung to his feet, beaming triumphantly.

“I used to do 400 pounds!” he boasted. “But the COVID, it put me back. I’m working my way back.”

Alcorn was in the midst of his weekly workout at the Strength Shoppe in Echo Park, where he and his wife, Patricia Alcorn, 88, have been training for 12 years. They’re devotees of an exercise called slow-motion strength training.

Often referred to as SuperSlow or Power of Ten, the resistance training technique involves lifting weights very slowly and methodically, with 10 seconds each spent on the lifting and lowering motions of the exercise. Doing so eliminates momentum and is therefore easier on the joints and connective tissue — one reason many fans of this type of training are in their golden years.

The workout is typically done using MedX equipment, weight machines that were developed in the 1980s for rehabilitative purposes. They’re still used in physical therapy clinics, hospitals and gyms.

Strength training has become a hot topic in the world of exercise, in part because research continues to show benefits for health and longevity. It builds muscle strength and bone density and is good for cardio metabolic health, especially for women. But slow-motion strength training, in particular, is beneficial for older exercisers, people healing from injuries or those who are new to or returning to exercise because the slow cadence and focus on form — always with one-on-one supervision — reduces the chance of injury.

The method has also caught the attention of the wider exercise community because of its efficiency: a slow-motion workout is just 20 minutes long, once a week. It shouldn’t be done more than that, so the body has time to recover, says Melinda Hughes, co-owner of the Strength Shoppe. Slowing down the movement, eliminating momentum and not stopping to rest during an exercise set puts the muscle under greater tension for a longer period of time, forcing it to work harder, so exercisers may see greater benefit in less time compared with traditional strength training. Muscles typically fatigue from the exercise in just one to two minutes.

“Whereas traditional strength training takes three times the amount of time, with more reps and sets,” Hughes says, “and you don’t get to the level of intensity that you do with slow-motion strength training, where you just do one set to failure.”

“It’s only 20 minutes. I can go on my lunch break,” says Lai-San Ho, a 33-year-old TV editor. She started slow-motion strength training at the Workout Revolution in Studio City after tearing her ACL in 2022; it provided a low- impact way to exercise while recovering. But she stuck with it to stay fit.

“I could tell I was getting stronger in all areas of my body,” Ho says. “I’ve noticed certain aches and pains in my upper back, after a year, went away. I can’t imagine not doing it because I feel so many benefits.”

Jason Zaremski, a sports medicine physician at the University of Florida, says the technique is “legit, the real thing.”

“Any weight training is great for older individuals, but this routine reduces risk of injury while still gaining benefit,” he says. “There’s no jerky motions or throwing of weights. And it can increase your circulation — you get greater blood flow while activating your muscles. So you’re adding a cardiovascular benefit for something that’s typically anaerobic.”

Other experts are skeptical about the technique.

“Sets going to failure, with a long time under tension, is a very uncomfortable, unnecessarily painful workout,” said Casey Johnston, author of the weightlifting newsletter “She’s a Beast.” “It’s not necessarily more effective. So much of lifting is about coordination, neuromuscular activity in your body and stabilization and that’s not present using machines the way it is with free weights.”

There are about a dozen boutique fitness studios in LA that specialize in slow-motion strength training, as well as larger chains like the Perfect Workout. Momentum around this subset of exercise picked up during the COVID-19 pandemic, Hughes says. While gyms and fitness studios closed during early stay-at-home orders, many slow-motion strength training studios remained open because they offered an essential rehabilitative service: weight-bearing physical therapy for pain management, osteoporosis and other conditions.

After restrictions lifted, those looking for in-person studios with strong COVID protections found their way to slow-motion strength training. The environment of a typical studio is quieter and more intimate than a bustling gym. No more than two clients and their trainers are typically allowed in the space at once. The temperature is set at a chilly 68 to 70 degrees, because body heat rises with such strenuous exertion. There are typically no group classes offered and no music over the loudspeakers.

“It’s so absolute attention can be paid to form and alignment,” Hughes says, adding that her clientele ranges from age 12 to 93. “I, and other trainers who work with this, call it ‘the fountain of youth.’ We lose muscle and bone density as we age. It’s cumulative. When you gain — or regain — muscle mass, you feel younger, your body is more supported.”

Though slow- motion strength training has delivered results for many participants, those results come with a price: Sessions must be done with a trainer and typically cost between $80 and $100, so that a month’s worth of sessions are more than a monthly gym membership.

Still, devotees say the cost is worth it.

“You cannot put a price on health,” says Blake Boyd, a 58-year-old actor- producer and former fitness instructor who came to the Strength Shoppe six years ago after having been diagnosed with arthritis in his neck. “It’s effective, it works. I’ll do it for the rest of my life.”