High Reps Vs Low Reps For Muscle Growth • Russ Howe PTI

Last updated:

25 July 2023

Ever wondered why my programs push you through a variety of different rep ranges? Here’s the science on high reps and low reps!

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7 min read

When I was a young lifter I was advised to stay away from high reps.

“The golden zone for muscle growth is 8-12 reps per set,” they said.

My girlfriend was told the opposite. She was instructed that ladies need to do high rep work, as this would tone their muscles and avoid a big, bulky appearance.

You know what?

It was all bullshit.

It turns out high reps are just as effective as low reps when it comes to building muscle. Furthermore, the key to unlocking the absolute best results is not to choose between the two different styles, but rather to use them both, because they each offer unique additional benefits which play an important role in helping you to build your best body.

Check it out below.

Why Do We Believe This?

The old belief that lifting heavy weights for low reps is the only way to build muscle has taken on a life of its own throughout the years, but it all stems from a piece of missing information.

You see, if you were to ask ten “experts” what the goal of each rep range is, I guarantee nine of them would tell you the following:

1-5 reps is for strength
8-12 reps is for hypertrophy (muscle growth)
15+ reps is for muscular endurance

So what would the one in ten expert say?

Well, this expert would give you a more complete picture. You see, each rep range has more than one benefit. That means the information above is not necessarily wrong, it’s just missing some crucial information, and it could change the way you train forever:

1-5 reps is for strength and neuromuscular development
8-12 reps is for hypertrophy and strength
15+ reps is for muscular endurance and hypertrophy

What The Studies Say

When I was a young lifter I wouldn’t have even entertained the idea that lighter weights and higher reps could possibly build muscle.

I was wrong on this.

The first study to provoke interest in this topic arrived in 2010 from researchers at McMaster University, Canada. The team were looking at the neurological differences between having a group of trainees go to failure (the point of being unable to perform another good rep) with a heavy weight for 4-5 reps, and with a light weight for 20-25 reps, when they noticed something interesting…

… at the end of the trial, the high rep group had increased muscle protein synthesis (the anabolic response to training) a whopping 60% more than the other group! (1)

About a year later, a second study from the same university replicated the results. (2)

Holy flaps!

Eyebrows were raised at this point, because until these findings, high rep training had never really been explored on a muscle building front, and the old belief that they were just for “toning up” was still considered true in most gyms.

However, the caveat to these early studies is that they weren’t giving us a true comparison between high reps vs low reps. That’s because using a weight which causes failure at 4-5 reps is more typically associated with gaining strength (as explained above), so if we really want to see how effective high rep work can be for hypertrophy, we must conduct a study comparing it to going to failure in the classic 8-12 rep range.

Thankfully, that study arrived the following year. (3)

In a detailed analysis published in the Journal of Applied Physiology, researchers from the same university had one group of trainees performing sets with a weight which caused failure at 8-12 reps, and another group of trainees using a weight which caused failure at 20-30 reps.

Amazingly, this resulted in a near identical spike in muscle protein synthesis, and by the end of the trial both the low rep trainees and the high rep trainees has increased muscle mass by 7%.

This is the study which quite literally changed the game.

can you build muscle with high reps and light weights

What About Women?

should women do high reps and light weights to tone up

Women have long been advised that they need to train differently to men in order avoid, well, looking like men.

That old belief is absolute horse shit.

I can categorically state right now that any women reading this have absolutely nothing to fear by venturing into lower reps and heavier weights, and there is no need for you to train any differently to a man – you will NOT end up looking like Rambo.

There are two reasons why…

First, because if it was that easy to look like Rambo then every guy in your local gym would look like Rambo, and they most certainly do not. Interestingly, Stallone was one of the pioneers of high rep training, so you’re possibly already training like Rambo right now.

Second, the body of a human female produces significantly less testosterone than the body of a human male. Testosterone is the key player in the muscle building process (that’s why guys inject it), meaning it’s actually HARDER for women to build muscle than it is for men. That’s right, ladies, if you’ve ever felt frustrated that your husband or partner seemed to find results easier to come by, you were not going crazy, it actually is easier for men! (4)

I hope that allays any fears you may have had about lifting heavy. I felt like I needed to include this section, because unfortunately the fitness world is still behind the times when it comes to educating women on how to train properly.

Using Both For Maximum Results

Now that we know high reps are just as effective as low reps for building muscle, it gives you some interesting options going forward.

If you’ve used any of my most popular training programs, you’ll know that I often combine the two alongside each other.

I do this because they complement each other nicely, each bringing a unique set of benefits to the table while simultaneously helping you to carve a leaner, more defined physique.

As you can see in the graph above, low rep work typically yields more strength gains as a secondary benefit, and high rep work generally leads to improvements in muscular endurance.

Here’s where the magic happens:

For guys who stay exclusively in the 8-12 rep range, their quest to build muscle hinges entirely on achieving progressive overload (increasing the weight they lift), but eventually they reach a ceiling in terms of how heavy they can go, which causes progress to stagnate, and injuries begin to rack up as years of heavy lifting takes its toll.

(I’m sure you can name a few guys like this at your local gym!)

Now, if we could introduce a high rep phase to their training, it would enable them to continue building new muscle, while also serving as an opportunity to give their joints and central nervous system a well-deserved break from heavy training. It would also increase their ability to push through “the burn”, which could help them go heavier when they return to low rep work.

That’s why I recommend following a well-structured training program which uses periodization to incorporate both types of training. This would help the trainee to unlock continuous results, while keeping them as injury-free as possible! (5)

I hope you’ve found this guide on high reps vs low reps useful. If you’re looking for a program which does all of the above, check your Members Area for my Train To Success program now.

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