Does Rep Count Even Matter? Controversial Findings of a Recent Study!

December 3, 2010

So I am going to to talk about a study that questions a lot of what you will read online regarding gaining strength and muscle. It was conducted a couple of years ago, but you won’t hear it being mentioned on most mainstream sites. This flies in the face of a lot of fitness programs. My point for bringing it up is to start a discussion on the findings. I will give you my take on this, but my hope is that others will chime in in the comment section.

rep count

[What if things like heavy weight vs low weight and high reps vs low reps didn’t make a difference? What if “effort” was the only variable that mattered in gaining muscle?]

First, I Will Reveal the Study…

So this study was published in the Journal of Exercise Science and Fitness (JESP). The cool thing about this journal is that the JESP website lets you download their PDF’s for free. The downside is that you can only access the last two years worth of issues (2009-2010)…and the study I’m referring to happened back in 2008. Luckily I saved it on my Desktop last year, so you can have access to it 🙂




Some Great Info, But Presented in a Dry Manner

These scientific papers have great info, but are as far from entertaining as you can get. The summary doesn’t do the paper justice either

“The size principle states that motor units are recruited in an orderly manner from the smaller (lower threshold) to the larger (higher threshold) motor units, and that the recruitment is dependent on the effort of the activity. Greater recruitment produces higher muscular force. However, the pervasive faulty assumption that maximal or near maximal force (very heavy resistance) is required for recruitment of the higher-threshold motor units and optimal strength gains is not supported by the size principle, motor unit activation studies, or resistance training studies. This flawed premise has resulted in the unsubstantiated heavier-is-better recommendation for resistance training.”

So Let’s Get Down to the Juicy Info About This Study!

So Dr. Ralph Carpinelli reviewed past scientific literature on the size principle and came to an interesting conclusion: It is the amount of effort NOT the amount of force that determines the degree of muscle fiber motor unit activation. So the heavier the resistance, the more force is required to lift a weight…but remember it is “effort” NOT force that is responsible for maximum muscle activation.

– – – – – – -> Effort VS Force <- - - - - - -

Dr Carpinelli explains it best by using in this example:

“If a person is holding a 20 kg dumbbell at an elbow angle of 90 degrees…the first 10 seconds may feel relatively easy. After about 60 seconds the person will no longer be able to hold the 20 kg mass.” <---So the force of 20 kg is constant, but the effort increased as the 60 seconds passed (interesting).

“At the point of maximal effort (~60 seconds), all the motor units in the pool were recruited for that specific isometric muscle action.”<---So the maximum effort is what recruited all of the muscle fibers, the force was just a secondary variable in this example.

Carpinelli Does Not Believe That Rep Count Matters

In this paper, Carpinelli found 20 studies that reported no significant strength gains from doing 2 reps to failure or 20 reps to failure —> “If a maximal—or near maximal—effort is applied at the end of a set of repetitions, the evidence strongly suggests that the different external forces produced with different amounts of resistance elicit similar outcomes.”

I Decided to Create a Quick Video Summary…


My Thought On This Study


There are a lot of variables that this study does not address: High total volume for gaining muscle vs low volume training. What happens to the muscle when you don’t train to failure. The different types of growth produced by high reps vs low reps. Like the findings of most studies, this is just a small snapshot at a few variables.

Go to failure if you want to build muscle: I believe in fatiguing the muscles over a series of sets with the final sets requiring maximum effort…in order to gain muscle. His study suggests reaching maximum effort for maximum muscle recruitment.

Higher reps can still build muscle: I’ve known this for ages, but if you are doing high reps close to muscular exhaustion…you are going to put on size. So even if you lift light, you can still add muscle. In fact I would say that higher reps are the best way to increase muscle size, due to the cumulative fatigue that “requires more effort” from set to set. Don’t let any recently certified personal trainer tell you otherwise!

Avoid failure…for strength without muscle size increase: This is an area the study doesn’t explore as much as I would have liked. The main point is that avoiding failure is a great way to consistently gain strength with very little muscle growth. Gaining strength is also a way to create muscle density (something this study doesn’t cover). My girlfriend does sets of 5 reps with weights that she could probably do 8 times. Over the past year she has gained a lot of strength and muscle tone, with ZERO increase in muscle size. Since she avoids maximum effort, she doesn’t need to worry about gaining muscle. Note: She wants to stay slim and lean instead of adding mass. My women’s course coming out in Feb 2011 is based upon this way of training.

Maximum force without maximum effort: So this is a similar point to my last point. If you want to increase strength without adding muscle then you would lift heavy (max force), but avoid failure (max effort).

Would like to see a study on the effects of avoiding failure: When I started this blog, I was almost 100% focused on increasing muscle definition WITHOUT gaining muscle. As Dr. Carpinelli shows in his study, training with maximum effort to failure is a great way to build muscle mass and strength…REGARDLESS of the reps being used. So what if you want to gain strength and build muscle density without putting on mass? Well, I have found the best way is to avoid failure altogether.

What is Your Opinion on This Study?

I never take the results of one study as the WORD on fitness. I just hope that I learn at least one tip that will improve my ability to create effective training programs. My biggest takeaway from this study was…reaching maximum effort on the last rep or two will help muscles grow regardless of the amount of reps being performed. If you have a particularly stubborn muscle then make sure you push those final reps hard with maximum effort.

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{ 15 comments… read them below or add one }

Sam March 6, 2011 at 9:00 pm

Great post. I’ve always thought that more effort = more gains. If you go in the gym, and do one rep of your max you’ll never really make any huge gains. However, if you go in the gym, and do 30 pounds below your max until you can’t put it up anymore, you’ll start to see great increases in the amount of weight you can lift as well as the size of your muscles. The harder you work, the more you get. That principle works in life as well as fitness.

Anyway, just my two cents! I’ve done high rep workouts that put half an inch on my arms in just a few weeks, and I’ve done low rep workouts where I didn’t make any gains. It all depends on how hard you work.

If you get a chance, I’d really appreciate it if you’d check out my blog! I’m trying to break down fitness in a methodical, sensible manner, starting with basic anatomy and physiology of the muscle groups of the body. I also just posted a basic 12 week workout program for beginners. Eventually, I want to get more and more advanced, creating a resource for anyone from the beginners trying to lose a few pounds to the veterans trying to add a few more pounds to their bench press. Hit up the site if you get a chance!

Sam — Dedicated Fitness

Abdonda March 17, 2011 at 11:28 am

Interesting post about reps. I think many people would agree with you that higher reps tend to build muscle.

Troy - Cube.Dweller.Fitness March 18, 2011 at 12:24 am

Maybe I’m more of a hardgainer, but I’ve worked several different rep patterns. This post matches my experience that working to fatigue matters most; often that means working in different rep patterns.

I’ve done so many different types of programs: low-rep, German volume training with 10 sets of 10, 100 rep workouts, tabata drills, and more.

The variation every 4-6 weeks pushes the body. I guess P90 followers would call it muscle confusion. The principle matters and this post nailed it — work to failure.

Craig March 19, 2011 at 6:03 pm

So an individual who went from 100lbs X 5 in the dumbbell bench press, to 150lbs X 5, while avoiding training to failure would not have bigger chest muscles? That does not make one iota of sense.
As to your GF or any other individual, would not gross cal intake have a far greater bearing on whether or not additional bulk was put on. Not to mention how much cardio was employed over that time. Too, assuming she is natural, muscle building for women is definitely no easy task.
Anyone with any time in the trenches knows from their own trial and error that they will respond to some rep brackets and not others, and that this may very well change over time. So reps don’t matter? Bollocks.
Finally, for a drug free individual training to failure exacts a hell of toll on recovery. So much of failure training is from hyped shrunken testicled juice abusers. For those of who don’t go down that road though? If you can save your reserves and avoid going to failure, but progress your strength to some pretty bloody impressive levels by using the rep ranges you respond to, you are going to be big and strong. But that kind of commonsense doesn’t sell mags or supps.

shane March 23, 2011 at 2:24 am

took the words right out of my mouth. I was thinking, if you do heavy loads, do negatives after failure or take some weight off and do as many reps as possible immediately. You may get full muscle recruitment and any unproven benefits of heavy weight training?

Louber March 28, 2011 at 3:29 pm

Hi Rusty,
First time commenter. I had Dr R. Carpinelli during the ACSM Health and Fitness Instructor cert (which I pass) Very interesting and informative. Saw him years later and he had gone from 10 reps to 20 super slow reps. Tried it and it was not easy; very intense. Not many clients continued with it, but had mixed results with those that did. One positive; shorter workouts and thus longer rest time.

Tatianna June 15, 2011 at 10:47 am

This is a very interesting concept. I always believed that reps didn’t matter at all, and now this article confirms my beliefs. I really love reading fitnessblackbook, I found more information here than I did studying for my Personal Trainer Certification.

Nicholas August 5, 2011 at 2:46 pm

Thanks for putting this together. It’s very interesting and it makes a lot of sense to me that exhausting the muscle, whether with a heavy or lighter weight is going to increase strength. I prefer to lift fast, but the results of the study are saying that tempo isn’t really important, just the resulting force that the muscle had to exert?

hello nfl October 5, 2011 at 3:35 am

Thanks for putting this together. It’s very interesting and it makes a lot of sense to me that exhausting the muscle, whether with a heavy or lighter weight is going to increase strength. I prefer to lift fast, but the results of the study are saying that tempo isn’t really important, just the resulting force that the muscle had to exert?

Exercise On Abs November 8, 2011 at 10:16 am

I was a hardgainer, but exercising in 45-60 sec interval got me the best results. For example : 12 reps x 4 seconds = 48 sec
you can do 10 reps x 5 sec= 50 sec
Nice post!

David @ The Natural Health Service January 3, 2012 at 4:33 am

I like your video, and agree that the study is too narrow to have much meaning really.

I do know for certain that you will not increase in strength (beyond the beginner stage) doing sets of 12 reps, but you will doing sets of 3 reps.

If you use short rest periods with low reps and cause fatigue at the same time you will also gain size. Of course the weights you are using will have to be a bit lower for this than if you were taking longer rest periods.

Training with max weight to failure with low reps will soon overtax the central nervous system and stop gains. And even with higher reps only your last couple of sets should be max effort.

John Oxnard April 28, 2012 at 9:38 pm

I recently watched the documentary “Pumping Iron” which is about Arnold Schwarzenegger and body building. I remember Arnold saying that “the last few reps are the ones that build muscle”. Being able to squeeze out those last few reps will be the reason you build muscle. So as long as you are pushing yourself to your limit either method is fine.

Rocky May 1, 2012 at 8:52 am

I have been using this technique for about 2 months. I am currently in a juvenile prison facility that does not let us use weights but I have been using this method with body weight. I have noticed increased strength but I still have maintained my lean build. Also I have proven, using the maximum effort technique I can increase in size using strictly body weight, something that all of the inmates deny.

J January 10, 2013 at 5:50 am

Studies, studies, studies. everyone is doing studies and coming up with different answers and all contradicting themselves. its a joke going on the internet trying to find what to do and what not to do.

Logan Bates March 26, 2013 at 8:55 am

Interesting study!! I’ve always felt more repetitions gives me a better workout (simply using bodyweight techniques) but then again I don’t really fancy myself a body builder, I prefer to have an athletic build! I guess it just depends on your own personal goals!

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