American men haven't won an Olympic weightlifting medal since the 1984 Games, when the sport's longtime behemoth, the Soviet Union, stayed home.

But a 15-year-old boy in small-town South Carolina is raising hopes for an American weightlifting renaissance. His name is C.J. Cummings, and at the 2015 USA Weightlifting National Championships this month in Dallas, he set a national record. In a sport where athletes typically peak in their mid to late 20s, this teenager lifted more than any American grown-up in his weight class had ever achieved.

"In 37 years of coaching, I've never seen anything like this kid," said Dennis Snethen, coach of the U.S. team at the Beijing Olympics and a former longtime top executive of USA Weightlifting. "He's the Michael Jordan of weightlifting in America."

That praise may sound faint, considering America's lack of stature in the sport: Its last two Olympic medals, awarded to women, came at Sydney 2000.

But as a youth, Cummings is becoming a force on the international stage. At the junior worlds this June in Poland, Cummings competed as a 15-year-old against athletes as old as 20 and finished fourth in the clean and jerk and seventh overall. At the nationals this month, his clean and jerk of 175 kilograms (about 386 pounds) broke not only the American national senior record but also exceeded by two kilograms the international youth record in his weight class (69 kilograms, or about 152 pounds). That record was unofficial, because it didn't occur at an international meet. But even on an unofficial basis, it tops anything any American weightlifter has accomplished in decades.

No American man competed in Cummings' weight class at the 2012 London Olympics. Of 18 international men who competed in that weight class in London, four racked up scores below Cummings's score at the nationals this month of 306 kilograms, a combination of his snatch and clean-and-jerk lifts. But that number falls far below the 332 that won a bronze medal at those Games.

A high-school sophomore in Beaufort, S.C., Cummings lives with his parents, trains an hour or two a day and studies enough to make the honor roll occasionally. When asked if he hopes to travel with the U.S. team to next year's Rio Olympics, he didn't hesitate. "Yes, sir," he said.

The second half of that response pleased his mother, Savasah Cummings, more than the first. "We've always told our children that manners will take you farther than money," she said.

Cummings belongs to a burgeoning force of Olympic-style weightlifters in the U.S. At USA Weightlifting, the sport's national governing body, membership has jumped to more than 22,000 from only 9,000 in 2012, said Michael Massik, its chief executive. A decade ago, it barely stood at 5,000. "We're seeing that kind of phenomenal growth in all categories—youth, junior and senior," Massik said.

In weight rooms across America, a cultural shift is taking place. For a long time, the weight room has been the province of power lifters, not Olympic-style lifters. For power lifters, the measure of an athlete is how much he can bench press—something not included in Olympic competitions.

Olympians execute the snatch and clean and jerk, movements arguably requiring more overall athleticism. During the clean and jerk, for instance, the athlete lifts a barbell off the floor and ultimately overhead, requiring balance and full-body strength, and particularly powerful legs.

The rising popularity of these lifts may be partly attributable to the popularity of CrossFit, which emphasizes Olympic-style lifting. A Brooklyn, N.Y., program called CrossFit Virtuosity offers a class called Olympic Weightlifting. "We place a heavy emphasis on Olympic Weightlifting due to the sport's unique ability to develop an athlete's explosive power, control of external objects and mastery of critical motor recruitment patterns," says the CrossFit Virtuosity website.

Actually, this trend represents a return to an age when Olympic-style lifting was prevalent in American weight rooms. In the history of the modern Olympics, dating to 1896, America ranks third in medals behind China and the Soviet Union/Russia.

Now, American weightlifting leaders are hoping for a return to those glory days. Only three U.S. weightlifters qualified for the London Games, compared with 10 for China. So the first step is for the U.S. team to do well at the IWF World Weightlifting Championship in Houston in November. "We anticipate sending more people to Rio than we did to London," said USA Weightlifting's Massik.

It remains to be seen whether Cummings will be one of them. To make the cut, an athlete must be ranked high internationally in his weight class, and to get there the teenager must continue to execute eye-popping lifts, starting with a meet next month in Mexico.

His coach, Rayford Jones, won't entertain any talk of Cummings ending America's weightlifting medal drought in Rio. "This is a 15-year-old boy, and we're going slow and steady," Jones said. "But you give this boy four years beyond Rio, you talk about the Tokyo Olympics, well, now that's a real opportunity."

Write to Kevin Helliker at [email protected]