Jim Stoppani explains the light weight vs heavy weight debate and which is best for optimal muscle growth.

For those who first start weightlifting, it might seem obvious that the more weight you lift the more muscle you gain. But that’s not necessarily true. There are various ways to build muscle and in today’s age of exercise science the tactics have become even more varied. But in the bodybuilding world, the biggest debate often comes down to light weight vs heavy weight. Aka – do you lift light weight with high reps or heavy weight and low reps? Both tactics are used by successful pro bodybuilders – proving their validity. But is one truly better than the other? In our latest GI Exclusive collaboration with Barbend, Jim Stoppani explains the light weight vs heavy weight debate and breaks down which is best for ultimate muscle growth.

For those who love bodybuilding and weightlifting, there is nothing more exciting than seeing someone lift an insane amount of weight (or performing it yourself). It’s the ultimate proof of your ability in the gym. A showcase of just how strong you’ve become with your years of training. From an outward glance, it then seems that lifting hardcore heavyweight is the most inspiring and motivational tactic a bodybuilder can commit to.

However, other bodybuilders have shown time and time again that light weight can be an effective tactic as well. Dexter Jackson, for example, is a former Mr. Olympia champion and also the most decorated bodybuilder in the history of the sport. He has always promoted light weightlifting at high reps over heavy weight. In fact, he claims it is the reason he was able to continue his pro career into his 50s.

So what’s the science behind this? Can we scientifically prove that one style of training is more effective than the other? We turned to Jim Stoppani to help answer the question.

Comparing muscle protein synthesis of light weight vs heavy weight

Jim Stoppani starts off by mentioning and study that compared two lifting tactics. One group of individuals lifted 30 reps of light weight. The other group lifted five reps of heavy weight. The study was focusing on muscle protein synthesis – a key factor in muscle growth.

What the study concluded, Jim Stoppani explains, is that both groups achieved the same amount of protein synthesis. But there was a catch. This was only true if the individual trained to failure. This study further cements the statements made previously on Straight Facts by Jerry Brainum. Particularly for lifting light weight, training to failure is necessary for optimal muscle growth.

This is easier said than done. Many individuals who lift light weight at high reps often believe they are hitting failure but are actually missing the mark. The mind is very powerful and can psych a person out from achieving the true limit of their strength abilities. More often than not, those who struggle building mass muscle with lightweight tactics simply aren’t training to failure enough.

So does this mean light weight and heavy weight training are equal?

With this study, it seems that training light weight or heavy weight comes down to personal preference – as it yields the same results. Jim Stoppani points out that this isn’t necessarily true. Stoppani explains that protein synthesis is not the only factor in muscle growth.

For example, Jim Stoppani explains how lifting heavier weight leads to increased strength. That increased strength allows for lifting even more weight. This all compounds to allow for increased muscle growth. This is like compound investing in the stock market rather than paying the same regular payment into a savings account.

On the flip side, Jim Stoppani explains how light weight at high reps is more effective at increasing blood flow. This bring more nutrients to the muscle – which helps bring benefits towards increased muscle growth.

Conclusion: combine light weight and heavy weight for best results

Ultimately, this is why Jim Stoppani always recommends a combination of both tactics. Not only does a change up to your routine every 4-6 weeks help prevent plateaus, but the mix of light weight and heavy weight will bring added benefits that would not be found in sticking only to one tactic.

Weightlifting and bodybuilding progress is never about finding one routine and sticking with it forever non-stop for the rest of your life. It requires constant variety, adaptation, and change to keep growth from plateauing.

You can watch Jim Stoppani go into full detail about light weight vs heavy weight training in our latest GI Exclusive interview segment above. Make sure to stick around each Monday for new episodes of Jim Stoppani’s explainer videos.

Derek Dufour has been managing all digital operations on the Generation Iron Network for over six years. He currently manages a team of editors, writers, and designers to provide up-to-date content across the GI Network.