Russ Howe PTI
Posted in: Training

High Reps Vs Low Reps For Muscle Growth

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High Reps Vs Low Reps For Muscle Growth / 6th May 2018

Training is a numbers game.

And today we'll look at high reps vs low reps to note the differences you can expect (and the myths) when it comes to building muscle.

But first, check out this email from website member Lucy Daniels:

"Hey Russ, my friends keep telling me to go higher in reps to gain size. I've always trained exclusively with lower reps, and it's always worked for me, but am I missing something?"

So let's get stuck in.

The first thing I'd like to say is that if you are training exclusively in the lower rep range (and your goal is muscle growth, not pure strength) then you are absolutely missing something.

In fact, some of the startling research I'll cover here will probably change the way a lot of readers train forever.

When I am designing a client's personal training routine or any of  my online workout programs for this website, I always like to include a combination of both high reps and low reps to optimize lean muscle growth.

Do not be fooled that higher reps are "for the girls" (eek!), or "for toning" (nope!).

High rep training has been shown to build just as much lean muscle as low rep training, so sticking purely to one rep range means you are losing out on potential results.

"Whoa.. wait a minute

Did Russ just say what I think he said?!

High reps are as good as low reps for building muscle?!"

Damn skippy.

And today I'll show you how to use high reps to build a stack of new muscle tissue.

high reps vs low reps

Olympic athlete Amanda Lightfoot during a recent circuit session at the gym.

The Battle Of Ego Mountain

There are three different rep ranges that we should be training in, each with their own primary goal.

These are things we are taught as trainers, and things we pick up from years of experience.

They are:

  • 1-5 reps for strength
  • 8-12 reps for muscle growth
  • 15+ reps for muscular endurance

So it makes sense that most guys see this analogy and stick mainly to the 8-12 zone, right?

That's the so-called "sweet spot" for muscle growth right there. As a result, most of us spend our entire lifting career hovering between as low as 5 reps, or as high as 12 reps, as this allows us to feel the most impressive with regard to the weights we can throw around.

But when you hear stories about Sylvester Stallone sticking primarily to a 20+ rep range while getting into Rocky IV shape, or The Rock and his crazy 50 rep sets on the leg press... Heck, even Arnold Schwarzenegger recommends incorporating higher rep ranges for building bigger arms...

And you wonder, "Am I missing something?"

Maybe.

Well, rather, the information in the little table above is not giving you the full picture.

It is missing out some crucial information.

Instead, it should read like this:

  • 1-5 reps for strength and neuromuscular connection (mind/muscle connection)
  • 8-12 reps for muscle growth and strength
  • 15+ reps for muscular endurance and muscle growth

does Sylvester Stallone do high reps

Sly Stallone is one of the pioneers of high rep training, and used it to get into what many consider to be his best ever shape.

STUDIES ON High Reps Vs Low Reps

Let's take a look at the available body of research surrounding training with various rep ranges.

The first study to really rock the boat regarding high reps vs low reps was published back in 2010. (1)

Researchers from Canada had a group of subjects perform 4 sets of leg extensions with the following training protocols:

  • Group A performed 1-5 reps with a weight which caused muscle failure at the target number of reps
  • Group B performed 25 reps with a weight which caused muscle failure at the target number of reps
  • Group C performed 25 reps with a weight which did not cause muscle failure.

Surprisingly, the group B (high reps to failure) came out on top, increasing muscle protein synthesis (muscle building) by an astonishing 60%!

high reps vs low reps for building muscle

This research opened many people’s eyes to the potential benefits of training in a high rep range, but one drawback of the study itself is that it used a 1-5 rep max as the comparison group.

If pure muscle growth is the goal then very few people would train for this low number of reps, so although the results were interesting (and a 2011 study compared the same protocols and came to the same conclusions) they didn't provide a 100% accurate comparison of whether high rep ranges are as effective as low rep ranges for building lean muscle. (2)

To get that answer, we have to revisit a study from the same university which occurred 2 years later...

This time around, researchers from McMaster University, Canada, directly compared the muscle building effects of using 8-12 rep sets versus 25 rep sets.

  • Group A performed 3 sets of leg extensions using a weight which caused failure at 8-12 reps
  • Group B performed 3 sets of leg extensions using a weight which caused muscle failure at 20-30 reps

The 10 week study was eventually published in the Journal Of Applied Physiology and it rocked the bodybuilding world as the first to conclusively prove that high rep training is just as effective for building muscle as low rep training.

Both groups increased muscle size by around 7%. (3)

is high reps good for muscle growth

While muscle growth was near enough the same regardless of the rep range used, the key difference between the two groups was that the lower rep trainees enjoyed a greater strength increase, while the higher rep trainees experienced a greater gain in muscular endurance.

One of the very best studies on this topic was published in the Journal of Strength and Conditioning Research in 2015, where researchers again concluded that muscle growth can be achieved when training with heavy weights for low (8-12) reps and when training with lighter weights for higher (25-35) reps, with the key differences being that the lower rep group noticed greater strength gains alongside the muscle growth, while the higher rep group noticed greater muscular endurance alongside their muscle growth. (4)

This also ties in with the information in the table above, and supports data from a previous (2007) study which found that cyclists performing low reps experienced greater strength gains in the leg press exercise versus cyclists performing high reps, despite both groups noticing similar improvements in overall muscle growth. (5)

During the 2012 study published in the Journal of Physiology which showed a 7% increase in muscle across both high and low rep ranges, the researchers concluded in their own words:

"In accordance with our previous acute measurements of muscle protein synthetic rates, a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure."

The key word here is failure. I'll explain below.

does The Rock do high reps

Why It All Works

In order to truly compare high reps vs low reps, we must take a look at what goes on inside the muscle when we perform a typical set.

Our muscles are made up of two very different types of muscle fibers.

  • Slow twitch fibers (weaker fibers with more endurance, but much less strength)
  • Fast twitch fibers (with much greater strength, but far less endurance).

When we perform heavy, explosive moves we develop our fast twitch fibers more. And most guys want to hit those fast twitch fibers because, after all, they’re the ones which have the largest potential for growth.

But the real “secret” lies in hitting both types of fibers.

You see, the human body tries to get away with doing the absolute minimum it can do, in order to keep you functioning at 100%. It looks for ways to make every task as easy as possible.

So when we lift something heavy, our muscles are recruited from smallest to largest.

Example:

Curl a heavy bar, and your slow twitch (the small, weak fibers) are the first to be recruited, as the body is trying to do as little as possible while still performing the task at hand.

Of course, they quickly realize they are no match for the weight involved and bail out on you, calling in some of the bigger fast twitch fibers instead. If the weight is still too heavy, all of the remaining fast twitch fibers from the muscles being worked are called into action and you get the weight up.

So that’s exactly what’s happening inside your biceps when you do a set of curls with a challenging weight for 8-12 reps.

The problem here is your fast twitch muscle fibers have been worked hard, but your slow twitch fibers have not been worked at all.

Remember, they bailed on you the moment it got tough!

how to build muscle

Let’s try it again, but this time we’ll use a weight which allows us to fail at 20-25 reps…

Example:

Once again, our biceps are going to recruit the slow twitch fibers as we start the exercise.

This time they can actually handle the stress (for the time being), and once the weaker fibers begin to fatigue, the cavalry is called and the bigger, fast twitch fibers take over again. If you’re using a weight which causes you to “fail” after around 20-25 reps, you will have worked both types of muscle fibers extremely hard.

That's the key difference between high reps vs low reps.

And that’s why high rep training is effective for building muscle!

Another point worth noting here is that studies show our levels of growth hormone increase dramatically as a by-product of lactic acid.

By training in a higher rep range, you will feel “the burn” (lactic acid build-up in the muscle being worked) much more, kicking your growth hormone levels into overdrive.

In the section above I mentioned that the key word was "failure".

I was talking about muscle failure.

You see,  training a muscle to failure (regardless of rep range) has been shown to increase muscle growth time and time again versus using weights which you can comfortably handle. For instance, the researchers in studies (1) and (3) both pointed out that the trainees who pushed to failure experienced greater results than those who were instructed to end their set before they reached a point of failure.

And this backs up the results of a 2012 study published in the Journal of Physiology which despite performing the same number of repetitions per set, a group of trainees who kept the working muscle under tension for longer (therefore achieving failure, while the other group did not) experienced far greater muscle protein synthesis (muscle building). (6)

And then there's the growing body of research behind newer training methods like  Kaatsu (blood flow restriction training) which shows that great muscle growth can still be achieved even when reducing training load to just 20% of your one rep max. (7, 8)

high reps for muscle growth

So while the golden 8-12 rep range will still be your best friend for muscle growth and strength gains, don't be afraid to go lighter and aim for more reps per set from time to time.

You're not at risk of "losing your gains" at all.

In fact, you'll be better preparing your body for superior results when you return to those lower rep ranges.

You see, by experiencing the muscle building results which are associated with higher rep ranges, you will also yield the muscular endurance benefits (improving your conditioning, and making your muscles capable of handling "the burn" to a greater degree), so when you switch back to using a lower rep range with a heavier weight you should notice that you are able to perform slightly better, too.

There are gains to be had all round, and that's why I have clients changing it up all the time.

high reps vs low reps

What About Girls?

If you’re a girl reading this, you might be panicking a little bit.

After all, for years women have been told to stay away from heavy weights or they run the risk of building up and looking like The Hulk in a prom dress.

But here I am telling you that you'll build just as much lean muscle with high reps...

What the heck are you supposed to do?

Well, the main thing this should show you is that the whole “you’ll get bulky” thing is absolute bulls**t.

Just like guys, girls should be training both types of muscle fibers for maximum results.

You have simply been misled for years (decades, even) by fitness industry nonsense which portrays higher reps as "for toning" and lower reps as "for the guys".

should women do high reps

Here's the truth:

  • Your muscles are incapable of "toning" (they'll grow or they'll shrink, how "toned" you look depends on body fat percentage)
  • You don't possess the testosterone levels necessary to "get huge" anyway

All those massive female bodybuilders you're worried you'll turn into if you pick up a challenging set of weights?

They're taking more than just the protein and amino acids they claim in the magazines, my friend.

The fact is, lifting heavy weights is pretty damn great for fat loss!

A study published in the American Journal of Clinical Nutrition found that subjects following a heavy weight training regimen were able to lose as much weight as subjects performing a cardio routine, but while the cardio group lost a combination of fat and lean muscle tissue, the weight training group lost the same amount of weight with a much greater percentage of body fat. (9)

Regardless of whether your goal is to gain muscle, to lose fat, one thing is very clear:

You have no reason to fear lifting weights, both for higher reps and for lower reps.

should women do higher reps and light weights

Rachel has dropped 6" so far and totally changed her body shape with a heavy weight lifting program.

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References:

  1. Burd, N. A., et al. Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise In Young Men. PLoS ONE 5(8): e12033, 2010.
  2. Burd, N. A., et al. Enhanced Amino Acid Sensitivity Of Myofibrillar Protein Synthesis Persists For Up To 24 Hours After Resistance Exercise In Young Men. J Nutr. 2011 Apr 1;141(4):568-73.
  3. Mitchell, C. J., et al. Resistance Exercise Load Does Not Determine Training-Mediated Hypertrophic Gains In Young Men. J Appl Physiol. in press, 2012.
  4. Schoenfeld, B. J., et al. Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. J Strength Cond Res. 2015 Oct;29(10):2954-63. doi: 10.1519/JSC.0000000000000958.
  5. Jackson, N. P., et al. High resistance/low repetition vs. low resistance/high repetition training: effects on performance of trained cyclists. J Strength Cond Res. 2007 Feb;21(1):289-95.
  6. Burd, N.A., et al. Muscle Time Under Tension During Resistance Exercise Stimulates Differential Muscle Protein Sub-Fractional Synthetic Responses In Men. J Physiol. 2012 Jan 15;590(Pt 2):351-62.
  7. Takarada Y, et al. Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion. J Appl Physiol 1985;88, 61-65.
  8. Weatherholt A, et al. Modified Kaatsu training: adaptations and subject perceptions. Med Sci Sports Exerc 2012;45, 952-961.
  9. Geliebter, A., et al. Effects of strength or aerobic training on body composition, resting metabolic rate, and peak oxygen consumption in obese dieting subjectsAm J Clin Nutr. 1997 Sep;66(3):557-63.

high reps or low reps