Lifting heavy weights is how you get strong.

We all know that.

However, since the adaptations caused by low-rep strength work are largely neural, many athletes who lift mainly in the 1-5-rep range never come close to maxing out their muscular development despite possessing decent relative strength.

Would some higher-rep “pump” work after your low-rep heavy sets help you build more muscle faster? In a study published in the Journal of Strength and Conditioning Research, Japanese scientists decided to test this hypothesis.

The Study

To start, they recruited 17 university students and had them perform Leg Presses and Leg Extensions twice per week over a 10-week period. All participants followed a hypertrophy-focused program for the first six weeks. Since the goal was to build muscle, they performed a high volume of work, with nine sets of 10-15 reps at 40-80% of their 1RM.

After the six-week mark, they switched to a strength-oriented plan for the final four weeks. In the strength phase, they performed five sets of 3-5 reps at 90% of 1RM.

But half of the participants also performed a “back-off set” after their last heavy set. This back-off set consisted of one additional set performed until failure with 50% of their 1RM. They performed this back-off set exactly 30 seconds after the completion of their final heavy set.

What happened?

Trainees who complemented their heavy sets with an additional, high-rep “back-off” set (25–35 repetitions) witnessed greater increases in 1RM leg strength, muscular endurance and thigh muscle size compared to those who did not. According to the researchers, these gains could be due to the higher training volume or higher growth hormone levels caused by the extra set.

How to Use This Information

Although they couldn’t pinpoint the exact mechanism behind the greater gains, the results were clear: A single low-intensity, high-rep “back-off” set potentiates greater muscle growth following the lifting of heavy loads. So, if you want to gain muscle size, simply strip some plates off the bar after moving big weights. You want to get down to around 50% of your one-rep max for the exercise. Wait 30-60 seconds, then bang out as many reps as possible (or close to it) for that one all-out set.

Depending on the movement and weight being utilized, don’t be afraid to venture into higher rep ranges than you normally would. The subjects in the above study used 25-35 reps for the back-off set and witnessed significant muscle gains.