Not everyone has an hour or more to spend inside the gym. Many people can’t spare more than 45 minutes for a training session. However, that doesn’t mean those who have less time on their hands for fitness have to renounce muscle gain. 76-year-old Arnold Schwarzenegger has a training approach that not only saves you time but also builds muscle.

Arnold Schwarzenegger revealed how a “specific method of super-setting exercises can lead to impressive results.” The study that Hollywood action icons cited divided participants into two groups who trained twice per week. However, only one group used the superset method and spent less time in the gym per training session.

Arnold Schwarzenegger wrote in his newsletter that the study found that “despite spending 36 percent less time in the gym,” the group that trained using supersets got similar results. The former bodybuilding champion also explained how the groups trained. The scientists used “antagonist supersets,” which means training opposite muscle groups.

Instead of the push-pull-legs approach, these individuals did one exercise and took a 20-second break. They then performed an exercise that trained the opposite muscle group and rested for two minutes. Meanwhile, the other group did straight sets, resting for two minutes between each set. To help standardize the study, researchers made both groups do the same full-body workout.

The FUBAR actor explained that scientists found both groups built “similar amount of muscle, strength, and muscular endurance.” However, the superset group tried for 44 minutes per session, while the straight-set group trained for 70 minutes per session. However, Arnold Schwarzenegger and his contemporary, Frank Zane, have spoken about other factors that may be prolonging your gym sessions.

Arnold Schwarzenegger and Frank Zane spoke about distractions.

While training with supersets would be one way of working out, Arnold Schwarzenegger also said that smartphones distract people from training. The 76-year-old wrote about watching people lose track of time between sets because they get distracted scrolling on their phones. Meanwhile, Schwarzenegger’s rival-turned-friend, three-time Mr. Olympia Frank Zane, highlighted a different kind of distraction.

Frank Zane also advised people to focus during their training sessions. “Don’t waste time daydreaming or talking between sets, and you’ll be done in less than an hour,” the 81-year-old posted on Instagram last week. Zane also recommended using lighter weights and resting less to finish a productive training session in 45 minutes.

So while you may think that having less than an hour is not enough for the gym, think again. Arnold Schwarzenegger revealed the science that says otherwise.