One of the most hotly debated topic when it comes to fitness professionals and hypertrophy is- the hypertrophy rep range. Hypertrophy as you all must know is defined as an increase in the tissue mass of an individual corresponding to an increase in his/her cell (muscle) size. This increase is achieved by regular exercising, more precisely weight lifting, strength training etc.
Anyone aiming to attain the max amount of hypertrophy must have asked themselves this particular question at one point in time or another. The question we are referring to is something along the lines of- exactly how many reps should be performed to optimise hypertrophy. Or more simply what is the ideal hypertrophy range?
At a first look it seems to be a simple enough question with a simple enough answer. After all, all that we are seeking to assess is the number of reps give us optimum hypertrophy results? Right?
Wrong! Turns out it is pretty difficult to get a unanimous opinion on what is the perfect rep range for hypertrophy, if such a things exists at all to begin with. There are so many different studies and expert opinions that will leave most of reeling in its after effects. We have tried to compile such studies and opinions and reach a viable conclusion. By the end of this article we hope you have some clarity about what is the hypertrophy range and how significant it is to train within it.
- There are two mechanisms at play when comes to hypertrophy i.e. mechanical tension and metabolic stress. Both these mechanism lie on either sides of the rep range, i.e. more of one means less of the other. The tug of war like relationship between these mechanisms leads us to believe that the hypertrophy range (if any) is quite flexible.
- Many bodybuilding and weightlifting professionals believe that there is a certain hypertrophy range which must be strictly adhered to if you want to optimise muscle growth. But as it turns out this might not be the case.
- It is true that low rep/ heavy weights build to more strength, and higher reps/ lighter weights build strength endurance. But same cannot be said about moderate reps/ moderates weights (hypertrophy range) when it comes to muscle building.
- And even if there is some truth to it, deviations from this hypertrophy range do not result in significant losses.
- Then again, even though hypertrophy range is spread more over the weight/rep combos, there is still a bare minimum which must be met for hypertrophy to come into effect.
Initially, the research on hypertrophy range was lacking and it led to wide variety of opinions on the matter. While some believe that the moderate rep/ moderate weights is the this range, which is the only way to optimum hypertrophy. Others believe that the range is a hoax and there is no ideal number of reps corresponding to optimum hypertrophy results.
With time there has been quite some progress in terms of research on this particular topic. However, it has still not led to a unanimous verdict in the matter of optimum rep range or hypertrophy range. Following article is our attempt to sort through the available research and reach a conclusion here.
The Mechanics Behind Hypertrophy
Before delving into the discussion about hypertrophy range, let’s first understand the mechanics behind hypertrophy itself.
So do you know how do muscles grow to begin with? No? Well here’s a little peak into the mechanics behind it-
There are two different types of mechanisms that lead muscle growth or hypertrophy. They are namely- metabolic stress and mechanical tension. It is important to note that these two mechanisms are not mutually exclusive, i.e. more of one (say metabolic stress) implies less of the other (corresponding mechanical tension), and vice versa .
Mechanical tension is related to the weight being lifted, and metabolic stress to the number of repetitions done. This is why more of one implies less of the other. Because when you add more weight to the bar it naturally means that you won’t be able to do as many reps you would have done with lighter weights. Thus meaning more mechanical tension but less metabolic stress. Since we know that both these mechanisms are in effect when it comes to hypertrophy and that, more of one means less of other, we can expect the hypertrophy range to stretch over a variety of weight and rep combos.
But what is the hypertrophy range that everyone is talking about and how essential is it to adhere to it? Let’s start by looking at some of the research regarding the same, and see where that leads us.
The Specifics of Hypertrophy Range
The first thing that we need to do is to clarify the specifics of hypertrophy range. The totality of rep ranges and weights lifted cannot be split into three categories .
- Low reps/ heavy weights i.e. weights ≥ 85% 1RM for sets ≤ 5 reps. Those looking for building strength should train within this range.
- Moderate reps/ moderate weights i.e. weights between 60-85% 1RM for sets of 6-15 reps.
- High reps/ light weights i.e. weights ≤ 60% of 1RM for sets ≥ 15 reps each. Those working on strength endurance must adhere to this range for best results.
The middle range mentioned above is considered to be the hypertrophy range i.e. one which results in best muscle growth. While the purpose of the low rep as well as high rep ranges have been verified, the same cannot be said about hypertrophy range. So let’s have a look at some research to get some answers regarding the same.
Many studies have been conducted to assess the impact of the hypertrophy range (moderate rep/weights) in comparison to other rep ranges. One such study was done by Schoenfeld  wherein a group of 17 trained men were split into groups of two. One group performed 3 sets of 10 repetition maximum and the other performed 7 sets of 3RM. At the end of the study the 3RM group showed 12.18% muscle size growth, and the 10RM group showed 12.17% growth. While both the groups independently experienced muscle growth, there was no significant difference observed in between the two.
Another study by Campos  performed on three groups of untrained individuals, called for a low rep group to perform 4 sets of 3-5RM, an intermediate rep group to perform 3 sets of 9-11RM and a high rep group to perform 2 sets of 20-28RM. At the end the low rep group showed 19.9% growth in muscle size, the intermediate group showed 17.1% growth, and the high rep group showed only 10% growth. This shows that while there may not be significant difference in hypertrophy over a broad rep range, there is definitely an upper and lower bound to it.
Mitchel et al. also  conducted a study on two groups of untrained men one of which performed 3 sets to failure at 80% 1RM and the other 3 sets to failure at 30% 1RM. The analysis showed 6.8% increase in muscle size for 80% group and 6.01% for the other. There was no record difference in hypertrophy within the groups in comparison.
Similarly a study by Van Roie  compared 3 groups of untrained older adults to check effects of low- and high-resistance training on muscle strength, volume and force velocity characteristics. The study resulted in a 3.2% muscle size increase in the group that performed 4x 10-15 at 80%1RM, 2.6% for group that performed 2×80-100 at 20%1RM and 2.4% for those that performed a mixed intensity workout of 20+40%1RM. The study failed to register any significant difference in hypertrophy amongst the groups, despite individual growth. Another study by Schoenfeld  comparing muscle growth in biceps, triceps and quads amongst two groups (low versus high load) showcased overall growth in various muscle groups but no significant difference when the groups where compared to each other.
Some of the more recent studies confirm that there is no long term/ significant benefit of sticking to the stipulated hypertrophy range. A 2016 study by Morton et al  studied two groups of moderately trained med one of whom performed 3 set of 8-12 reps, other 3 sets of 20-25 reps for various exercises, all taken to failure. There was no record significant different in growth measures between the groups, despite individual growth. A meta-analysis conducted by Brad Schoenfeld et al  compared hypertrophy post low-load, i.e. <60%1RM and high-load i.e. ≥60%1RM training. The analysis shows that hypertrophy is same when comparing moderate load training results to the results of low-load training.
Another study aimed to determine the effects of different intensities of resistance training on hypertrophy and muscle strength. The study by Thiago Lasevicius et al.  equated volume load between test subjects, and the sets were taken to failure. Its conclusion showed nearly identical biceps and quad hypertrophy for 40%, 60% and 80% 1RM. However they also observed that the growth was halved for those who performed at 20% 1RM. This study does not only reiterate the conclusions for earlier studies, but also gives us a unique insight. It shows that the stipulated ‘hypertrophy rep range’ is much bigger and flexible than what we originally thought. However there is a bottom limit to the range.
There are many other professionals who believe that the ‘hypertrophy range’ is not all that rigid as traditionally claimed. But even so, there is a lower and upper limit. Evan Peikon for example believes there is a maximum and minimum intensity threshold when it comes to hypertrophy training. Which according to him is between 30% and 90% of 1RM .
Gerg Nuckols from Stronger by Science , conducted a concise comparative analysis of various studies (some of which are already mentioned above). He performed required adjustments to give each study justifiable and fair importance in the analysis. The results he reached are as follows:
- The first observation made compared the hypertrophy range to the overall average results of various studies. Note that the ‘hypertrophy range’ in question is 6-15 reps per set. A comparison of unadjusted values within the studies showed no effective difference between hypertrophy results. Adjusted values on the other hand did show minor differences wherein means for low rep ranges out-performed means for moderate reps by 7% on an average. And means for moderate reps out-performed means for high reps by 8% on average. The results still did not show any significant difference between various rep ranges when it comes to hypertrophy impact.
- The next observation was made comparing the effect sizes for hypertrophy range against high and low reps. The average effect size for low rep measurements was calculated at 0.68, and that for moderate reps was 0.71. After making necessary adjustments for comparing moderate to high reps, the average effect size for high reps was 0.85, and for moderate reps was 0.99. In both the cases there is no significant difference between the rep ranges.
- The last point of comparison was made in terms of percent muscle growth in each individual study. Of all the 9 studies which were used to compare hypertrophy between low reps and moderate reps, 3 studies favoured moderate rep range, 3 favoured low rep ranges and the remaining 3 were ties between the both.
Next of a total of 14 studies studied hypertrophy impact caused by high reps vs. moderate reps. Of these, 6 studies favoured high rep range, 5 favoured moderate rep range and the remaining 3 were ties. Pooling the results for all the studies together, none showed significant difference between the impacts made by different rep ranges on corresponding hypertrophy.
It is safe to say that if a hypertrophy range does exist, it is quite widespread and cannot be fixated to a definite rigid interval. For those who accept 6-15 reps per set to be the hypertrophy range, may experience somewhat better results. But the overall advantage of strictly adhering to this range does not completely justify altering your whole training routine around the hypertrophy range.
It is best to train in a variety of ranges to make the most of a training routine as a whole. Moreover, also logically speaking there is no way to make sure that a certain defined hypertrophy range will work for each everyone looking to gain muscles out there. In this sense it is best to train in all rep ranges, including moderate range, and stick to what works best for you.
- Greg Nuckols. (February 25, 2016). The “Hypertrophy Rep Range”- Fact or Fiction? Retrieved from- https://www.strongerbyscience.com/hypertrophy-range-fact-fiction/
- Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Sonmez GT, Alvar BA. Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. J Strength Cond Res. 2014 Oct;28(10):2909-18. Retrieved from- https://pubmed.ncbi.nlm.nih.gov/24714538/
- Campos GE, Luecke TJ, Wendeln HK, Toma K, Hagerman FC, Murray TF, Ragg KE, Ratamess NA, Kraemer WJ, Staron RS. Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol. 2002 Nov;88(1-2):50-60. Retrieved from- https://pubmed.ncbi.nlm.nih.gov/12436270/
- Mitchell CJ, Churchward-Venne TA, West DW, et al. Resistance exercise load does not determine training-mediated hypertrophic gains in young men. J Appl Physiol (1985). 2012;113(1):71-77. Retrieved from- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3404827/
- Van Roie E, Delecluse C, Coudyzer W, Boonen S, Bautmans I. Strength training at high versus low external resistance in older adults: effects on muscle volume, muscle strength, and force-velocity characteristics. Exp Gerontol. 2013 Nov;48(11):1351-61. Retrieved from- https://pubmed.ncbi.nlm.nih.gov/23999311/
- Schoenfeld BJ, Peterson MD, Ogborn D, Contreras B, Sonmez GT. 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. Retrieved from- https://pubmed.ncbi.nlm.nih.gov/25853914/
- Robert W. Morton et al. (July 6, 2016). Neither load nor systemic hormones determine resistance training-medicated hypertrophy or strength gains in resistance-trained young men. Retrieved from- https://journals.physiology.org/doi/full/10.1152/japplphysiol.00154.2016
- Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW. Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. J Strength Cond Res. 2017 Dec;31(12):3508-3523. Retrieved from- https://pubmed.ncbi.nlm.nih.gov/28834797/
- Lasevicius T, Ugrinowitsch C, Schoenfeld BJ, Roschel H, Tavares LD, De Souza EO, Laurentino G, Tricoli V. Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy. Eur J Sport Sci. 2018 Jul;18(6):772-780. Retrieved from- https://pubmed.ncbi.nlm.nih.gov/29564973/
- Evan Peikon. (September 13, 2019). Training intensity and why rep ranges don’t matter for hypertrophy. Retrieved from- https://evanpeikon.medium.com/training-intensity-and-why-rep-ranges-dont-matter-for-hypertrophy-1e6c58443c1f