By Russell Taylor | Reading Time: 11 minutes |

Before I get into this, if we are monitoring goal sets per workout (even though there’s some debate) most experts (Nuckols, Beardsley and Krieger for example) agree counting less than 5-8 reps may compromise hypertrophy per set. Luckily enough most of these papers are based on the typical hypertrophy range of 6/8-12. We do know the hypertrophy range is a bit of a myth but very low reps (<6) you will have to do more sets to equate growth.

A review of the current literature and a theoretical limit to maximal Hypertrophy per session.

Recent Ultra-High Volume Training Studies: Are These Simply Frequency Papers in Disguise?

Studies that favour very high volume

Recently there has been quite a stir recently over the 2019 Schoenfeld et al. paper titled “Resistance Training Volume Enhances Muscle Hypertrophy but Not Strength in Trained Men”^[1]Schoenfeld, BJ., et al. (2019): Resistance Training Volume Enhances Muscle Hypertrophy but Not Strength in Trained Men. In: Med Sci Sports Exerc. URL: https://www.ncbi.nlm.nih.gov/pubmed/30153194..

This paper displayed superior growth, in trained lifters, with volumes up to 30-45 sets per muscle groups (listed as 5 set in the graph).  Which was an unfathomable amount of volume you could recover from, based on traditional thinking.

Results stated in 8 weeks are if you were interested:

• Elbow extensor: +1.1% (6 sets) versus 5.5% (30 sets)
• Mid-thigh hypertrophy: +3.4% versus 12.5%.
• Lateral thigh hypertrophy: +5.0% versus 13.7% in the lowest and highest volume conditions.

An interesting note was there were less low responders with higher volumes.

Schoenfeld came under a lot of fire for shortfalls in methodology (not waiting for the fluid retention^[2]Howatson, G. / Milak, A. (2009): Exercise-Induced Muscle Damage Following a Bout of Sport Specific Repeated Sprints. In: J Strength Cond Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/19826279. to drop or not being blinded when doing the scans are two examples) but we have to remember this is a replication of a previous study from Radaelli et al. (2015) ^[3]Radaelli, R., et al. (2015): Dose-response of 1, 3, and 5 sets of resistance exercise on strength, local muscular endurance, and hypertrophy. In: J Strength Cond Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/25546444.

Change in muscle thickness (MT) during the 8-week study period. The subjects trained either with 1 set per muscle group per unit (1 SET), with 3 sets per muscle group per unit (3 SET) or with 5 sets per muscle group per unit (5 SET). (Graphic Source: Schoenfeld et al., 2019)

Radaelli et al. (2015) in military personnel had a similar outcome in 30+ sets (listed as 5 set).

Muscle thickness (MT) in elbow flexor and extensor (left arm) before and after the 6-month training. * p ≤ 0.05 statistically significant difference compared to pre-training value; # p ≤ 0.05 statistically significant difference compared to control group (CG); † p ≤ 0.05 statistically significant difference compared to 1-SET group; & p ≤ 0.05 statistically significant difference compared to 3-SET group. CG = control group; MT = muscle thickness. (Graphic Source: Radaelli et al., 2015)

Now we need to examine the counter-evidence which showed more moderate volumes gave better results.

Amirthalingam et al. (2017) – 1 years’ experience. If you read the full text it was 9 vs 14 sets a par, if for example you count bench press and incline press together. Hypertrophy favoured the lower 9 set group^[4]Amirthalingam, T., et al. (2017): Effects of a Modified German Volume Training Program on Muscular Hypertrophy and Strength. In: J Strength Cond Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/27941492..

The training protocol used during the 6-week study period in the 10-set group (actual 14 sets/muscle group) and the 5-set group (actual 9 sets/muscle group). (Graphic Source: Amirthalingam et al., 2017)

Body composition and muscle thickness before and after the 6-week training with 10 (14) sets and (9) sets per muscle group. (Graphic Source: Amirthalingam et al., 2017)

Barbalho et al. (2018) – on trained women performing 5/10/15/20 sets per muscle group per week^[5]Barbalho, M., et al. (2019): Evidence for an Upper Threshold for Resistance Training Volume in Trained Women. In: Med Sci Sports Exerc. URL: https://www.ncbi.nlm.nih.gov/pubmed/30779716.. What’s interesting is historically and hormonally (as oestrogen is protective) women are usually more resistant compared to men, and yet benefited the most on 5-10 sets a week depending on the muscle group (quads preferred a little more volume than pecs for example). It should be noted Barbalho did a follow-up study in 2019 in men which showed similar results^[6]Barbalho, M., et al. (2019): Evidence of a Ceiling Effect for Training Volume in Muscle Hypertrophy and Strength in Trained Men – Less is More? In: Int J Sports Physiol Perform. URL: https://www.ncbi.nlm.nih.gov/pubmed/31188644..

Heaselgrave et al. (2019) showed in “experienced men” that the moderate group that performed 18 sets per week in 2 sessions, did better than the 9 or 27 set group, but the 27 group got largest strength increases ^[7]Heaselgrave, SR., et al. (2019): Dose-Response Relationship of Weekly Resistance-Training Volume and Frequency on Muscular Adaptations in Trained Men. In: Int J Sports Physiol Perform. URL: https://www.ncbi.nlm.nih.gov/pubmed/30160627.. The 9 set group, once a week, did the worse.

Left: Representation of the muscle thickness (MT) in the biceps (dominant arm) as average value (A1) and as individual percentage change of muscle thickness (B1). Right: Isometric maximum voluntary contraction (MVC) in the dominant arm as average value (A2) and as individual percentage change of MBC (B2). The dotted line in B & D represents the group average. HIGH (n=17): high weekly training volume; MOD (n=15): moderately high weekly training volume; LOW (n=17): low weekly training volume. (Graphic Source: Heaselgrave et al., 2018)

Papers that examine frequency directly with similar volumes

Saric et al. (2019) – Showed a trend in trained subjects that more acute volume leads to better hypertrophy^[8]Saric, J., et al. (2019): Resistance Training Frequencies of 3 and 6 Times Per Week Produce Similar Muscular Adaptations in Resistance-Trained Men. In: J Strength Cond Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/30363041.. In this case, 3x frequency did better than 6. This works out to be 4 sets per day, which worked better than 2 per muscle group.

Summary of study results by group (training frequency of 3 or 6 times per week). RT3 (n=14): 3 workouts/week; RT6 (n=13): 6 workouts/week. (Graphic Source: Saric et al., 2019)

Zaroni et al. (2019) demonstrated in subjects with 2 years’ experience that 15 sets is too much volume to handle vs 3 sets spread out^[9]Zaroni, R., et al. (2018): High Resistance-Training Frequency Enhances Muscle Thickness in Resistance-Trained Men. In: J Strength Cond Res. URL: https://www.researchgate.net/publication/326055694_High_Resistance-Training_Frequency_Enhances_Muscle_Thickness_in_Resistance-Trained_Men., which is similar to Barbalho.

Change in muscle thickness of the elbow flexors (MTEF), triceps (MTTB) and the outer thigh muscles (MTVL) by group. TOTAL (n=9): whole body training, 5 workouts/week, 3 sets per muscle group/workout; SPLIT (n=9): split training, 5 workouts/week, 15 sets per muscle group/workout. (Graphic Source: Zaroni et al., 2019)

Yue et al. (2018) mirrored Saric, showing 2 sets per session is sub-optimal vs 4 per session^[10]Yue, FL., et al. (2018): Comparison of 2 weekly-equalized volume resistance-training routines using different frequencies on body composition and performance in trained males. In: Appl Physiol Nutr Metab. URL: https://www.ncbi.nlm.nih.gov/pubmed/29216446..

Change in body composition (A & B), muscle circumferences (C & D) and bench press & flexion power at an intensity of 1 RM (E) and bench press power at 50% of 1 RM (F) before and after a 6-week low volume per workout training program at high training frequency (LV-HF, n=9) or high volume per workout at low training frequency (HV-LF, n=9). (Graphic Source: Yue et al., 2018)

Strength related papers, training systems or data

I have had to make some reasonable assumptions for this section, but decided to include these.

Although the Schoenfeld paper didn’t show strength increases it was short term and data does exist to show strength in elite athletes is linked to hypertrophy over the long term in papers such as Lovera et al. (2015) which I quote^[11]Lovera, M. / Keogh, JWL. (2015): Anthropometric profile of powerlifters: differences as a function of bodyweight class and competitive success. In: J Sports Med Phys Fit. URL: https://www.researchgate.net/publication/271331626_Anthropometric_profile_of_powerlifters_Differences_as_a_function_of_bodyweight_class_and_competitive_success.:

Also, Brechue et al. (2002) stated^[12]Brechue, WF. / Abe, T. (2002): The role of FFM accumulation and skeletal muscle architecture in powerlifting performance. In: Eur J Appl Physiol. URL: https://www.ncbi.nlm.nih.gov/pubmed/11990746.:

Rhea et al. (2005) showed optimal sets per session was around 8 in athletes^[13]Rhea, MR. / Peterson, MD. / Alvar, BA. (2005): Applications of the dose-response for muscular strength development: a review of meta-analytic efficacy and reliability for designing training prescription. In: J Strength Cond Res. URL: https://pdfs.semanticscholar.org/bfe1/b16ad8fc1d22f1de6bfa4adcb92bedde0980.pdf..

Volume of training: the number of sets performed (per muscle group) during each workout. (Graphic Source: Peterson et al., 2005)

Wernbom et al. (2007) did a systematic review on all the literature on hypertrophy at the time^[14]Wernbom, M. / Augustsson, J. / Thomeé, R. (2007): The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans. In: Sports Med. URL: https://www.researchgate.net/publication/6479274_The_Influence_of_Frequency_Intensity_Volume_and_Mode_of_Strength_Training_on_Whole_Muscle_Cross-Sectional_Area_in_Humans.. If we use 10 reps as the standard we are looking around 4 to 7 sets per session based on experience level.

Alexander Sergeyevitch Prilepin was a USSR coach and researcher who put together some general recommendations for lifters. Using the hypertrophy intensity mirrored in most of the above papers the 70-80% 1 RM (of 1 rep maximum) seems to be the most applicable giving you a rough guideline of 3-6 sets per session.

There is no real limit on frequency in the table as some trained daily or more.   The minimum of 6 reps for 3 sets is probably the closet guess we can make here.

Limiting Injury risks and disclaimers

First of all, none of this is prescriptive advice. The big issue here is people will jump straight into high volumes. Unfortunately one of the most linked causes of injury are rapid increases in volume and or intensity which was shown in a systematic review by Jones et al. (2017) on 68 papers concluded^[15]Jones, CM. / Griffiths, PC. / Mellalieu, SD. (2017): Training Load and Fatigue Marker Associations with Injury and Illness: A Systematic Review of Longitudinal Studies. In: Sports Med. URL: https://www.ncbi.nlm.nih.gov/pubmed/27677917.:

So, if you are going to try higher volumes a slow increase in volume over time then an assessment each step is required to check progress, the onset of fatigue and help reduce injury risk. Eckard et al. (2018) also gave a similar conclusion^[16]Eckard, TG., et al. (2018): The Relationship between Training Load and Injury in Athletes: A Systematic Review. In: Sports Med. URL: https://www.ncbi.nlm.nih.gov/pubmed/29943231.:

One thing to consider is in the Schoenfeld et al. (2014) study: People who trained at a lower intensity (10 rep max) were able to do more productive volume than the lower rep group (3 rep max) with less fatigue and less injuries but had similar growth^[17]Schoenfeld, BJ., et al. (2014): Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. In: J Strength Cond Res. URL: https://www.ncbi.nlm.nih.gov/pubmed/24714538.. So going really heavy is probably not advised when trying to do a lot of sets.

Are you toying with the idea of running a high-volume program? Increase the volume slowly, because otherwise you risk unnecessary injuries. (Image Source: Fotolia / jomkwan7)

Some early evidence may suggest that a 20 rep widow maker squat for example might cause more fatigue than a 10 rep with similar growth so the range of 6-12 reps makes more sense than say 3 or 20.

What I think is happening is that

1. Trained people are more resistant to damage

The above papers (and several not listed) seem to suggest novice lifters require less volume to progress. They are more responsive to stimulus and also seem to be easier to damage as they are not used to the repeat bout effect which leads to point 2.

2. Frequency is modulating how much damage is happening per session

Growth can be independent of actual tissue damage, the higher frequencies seem to be modulating the amount of damage caused in-between each session allowing less recovery time that required to first repair the tissue then initiate growth. This is supported by Damas et al. (2018) which states^[18]Damas, F. / Libardi, CA. / Ugrinowitsch, C. (2018): The development of skeletal muscle hypertrophy through resistance training: the role of muscle damage and muscle protein synthesis. In: Eur J Appl Physiol: https://www.ncbi.nlm.nih.gov/pubmed/29282529.:

3. The quality of lifting is improved on higher frequency

As during marathon sessions work capacity becomes compromised and you may have to use overall less volume toward the tail end of the session. So probably doing less productive sets.

My anecdotal experience as an elite lifter

I have personally done routines such as Sheiko which would easily be within Schoenfeld study sets and managed it fine, however, the program is more submaximal.

That being said, due to Schoenfeld short rest time it would have been impossible to do such low rest times and have maximal output to failure every set. An argument can be made for leaving 1 to 3 reps in reserve to manage fatigue to lower injury risk and most of the data out there suggest going to failure is not required to growth^[19]Sampson, JA. / Groeller, H. (2016): Is repetition failure critical for the development of muscle hypertrophy and strength? In: Scand J Med Sci Sports. URL: https://www.ncbi.nlm.nih.gov/pubmed/25809472.. I have also done Smolov and instantly scaled volume and intensity up significantly and resulted in my worse knee injury to date.

In my last prep after a year stalled an additional 20% volume gave me notable increases in muscle and strength. The key to even to get up to these levels is to manage fatigue but that’s a large different topic.

Practical recommendations

First, we need to look at the table:

• Looking at the table doing less than 3-4 sets per session per part may not provide enough initial stimulation but is probably way better than doing nothing.
• However, if doing more than 8-10 sets per session it may be beneficial to spread the volume onto an additional day. This may reduce interest fatigue and allow better movement practice as there are more fresh reps.
• You may never require more than 20 sets, so requiring more than x2 frequencies which reflect the current literature as 30 sets or more studies are rare. So if doing fewer than 8 sets per session frequency is mainly a modulator of weekly volume.
• If you are going to go up to those volumes do it slowly, monitor progress and only try it on 1 part as a specialization cycle.
• Novices require less volume than advanced, too much early on might slow progress.
• Volume increases can force a low responder to lifting to grow better.

Amendment since researching this I came across Haun et al. (2018), “Effects of Graded Whey Supplementation during Extreme-Volume Resistance Training” – this study had trained lifters at 3x frequency and gains in mass tapered off after 20 sets per part per week^[20]Haun, CT., et al. (2018): Effects of Graded Whey Supplementation during Extreme-Volume Resistance Training. In: Front Nutr. URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141782/.. The highest volume session having 8 sets per body part performed the best.

Title Image Source: Fotolia / Oleg Samoylov