Scientists Show the Rock’s Muscle-Building Workout Move Really Works

• Dwayne “The Rock” Johnson uses eccentric exercise to build muscle, his strength coach says.
• It involves lengthening muscles under tension, such as when you lower a weight (called a negative rep).  
• Eccentric exercises can build strength and more muscle in less time, research suggests. 

Don’t just focus on lifting weights — lowering them may help you build as much muscle in half the time, a small new study suggests.

Researchers from Edith Cowen University in Australia tested different types of dumbbell exercises on a group of 53 university students over 10 training sessions in five weeks. 

They found that the most efficient way to build strength and muscle was focusing on the lowering portion of exercise — known as “eccentric contraction,” or putting tension on muscles as they lengthen.

Their findings won’t come as a surprise to Dwayne “The Rock” Johnson, who is one of many elite athletes to swear by eccentric exercise. This specific move was a crucial part of The Rock’s Black Adam workouts to take his fitness to the next level, his strength and conditioning coach Dave Rienzi told Insider. 

According to the study, published September 2022 in the European Journal of Applied Physiology, participants who did eccentric exercise had the same strength gains, and more muscle growth, but did half the amount of reps, compared to their peers who did more typical exercise (raising and lowering weights). 

“This latest study shows we can be far more efficient in the time we spend exercising and still see significant results by focusing on eccentric muscle contractions,” Ken Nosaka, co-author of the study and professor of exercise and sports science at Edith Cowen University, said in a press release. 

How to do a ‘negative’ rep 

Most traditional exercises also include a concentric contraction, which involves shortening the muscle, often by lifting a weight.

Concentric exercise has benefits for improving strength and endurance, so doing both types of exercise (concentric and eccentric) can help you be a well-rounded athlete, Chris Travis, owner and coach at Seattle Strength and Performance, previously told Insider. 

You can do eccentric versions of exercises with dumbbells, a barbell, kettlebells, or body weight too. An eccentric exercise involves controlling a weight while lowering it, sometimes called a negative rep.

Examples of eccentric exercises with body weight include:

• Creating a tempo by counting to five as you lower into a squat or lunge
• Slowly descending from the top of a pull-up
• Lowering yourself to the bottom position of a push-up

If you’re using weights, Nosaka recommended using both arms to lift a weight, and then using a single arm to lower it for exercises like a shoulder press, bicep curl, or overhead extension. Gym machines like knee extensions and leg curls can help you use a similar technique for lower body gains, he said in the press release. 

Eccentric exercise can build muscle in fitness newbies or pro athletes

One advantage of eccentric exercise is that it can be safe for beginners and helps develop good form and prevent injury, according to Travis.  

“We do a lot of eccentric work because it builds muscle really well and we do it in a way that people who are starting in strength training aren’t moving too quickly and are understanding the range of motion,” he said. 

But they’re just as good for seasoned athletes, The Rock’s strength coach Rienzi previously told Insider.