Note from Greg:
This guest post comes from Dr. Eric Helms. If you don’t know Eric, he’s a successful coach for 3D Muscle Journey, an INBA natural pro bodybuilder, a scientist, and an all-around brilliant human being. If you didn’t know already, he’s one of my partners (along with Dr. Mike Zourdos) for MASS – a monthly research review breaking down the latest science that’s directly relevant to strength and physique athletes.
As the evidence mounts, it becomes more and more clear that hypertrophy can effectively occur at heavy, moderate, light, and even very light loads (as confirmed by the most recent meta-analysis on this topic [1]). However, the caveat is the data on this subject are almost entirely on sets taken to failure. Considering heavy-load sets result in high muscle activation right from their initiation (more on this in a bit), it’s probably the case that light-load training needs to be completed at or near failure to be comparable to heavy-load training on a set-to-set basis (2).
For anyone who is late to the party thinking, “Say what? I thought load needed to at least be adequately heavy to be effective for hypertrophy,” let me clarify before getting to the meat of the article.
When you’re lifting heavy weights (~80% 1RM+), the vast majority of muscle fibers are recruited from the beginning of a set’s initiation (3, 4). Muscle fibers are under mechanical strain – the primary driver of hypertrophy – right away. However, low-load training to failure also puts a vast majority of fibers under mechanical strain … eventually. How? Well, in a set of 30 reps to failure, as low recruitment threshold fibers become fatigued, high recruitment threshold fibers are recruited to “pick up the slack” (5). Subsequently, they too end up getting fatigued and are unable to continue to produce force as failure approaches. Thus, at the individual fiber level, by the time you reach the final reps of a high-rep, low-load set, all fibers in the trained muscle are recruited and exposed to a mechanical tension stimulus.
This is good news, right? It means you can train with low loads and potentially experience less joint strain and still progress (if your goal is hypertrophy). However, progressive overload still matters. If you decide to just train in the 12-20 rep range, you should still be getting stronger in that rep range over time, as this would indicate you are indeed increasing muscle size. Also, let’s step away from the mechanism and consider some practical limitations of low-load training near to failure before we start talking about implementation.
1. High-rep sets to failure on certain exercises are disproportionately fatiguing compared to other exercises: A couple of recent studies highlight this point nicely. In one study, participants reported greater discomfort performing knee extensions to failure with 30% compared to 80% of their maximum voluntary strength. In a similar study, resistance-trained males had greater suppression of force production (their strength was lower) after completing four sets of leg extensions with 30% 1RM compared to 80%. In simple terms, there is a reason 20-rep sets of squats are called “widow makers.” When performing high-rep lower body movements, cardiovascular and local muscular fatigue reach extreme levels. Having done this in my earlier lifting years, I can tell you that rest periods have to increase, motivation is quickly sapped, puking becomes a real possibility, and the likelihood of you completing RDLs, lunges, leg extensions, leg curls, and calf raises with any quality after you finish 3×20 on squats is very low. And by the way, widow makers aren’t typically even done to true failure (which we’ll discuss in a second).
2. Training programs in studies make concessions: When a study is conducted, researchers have to create a program that is not too time intensive for the researchers and the participants, and they have to cater to the lowest capability level of the participant cohort (within the specific population) to ensure completion. The necessity of these concessions results in pretty unrealistic training programs compared to the real world. Specifically, participants in studies often train 2-3 times per week, often performing just 2-4 exercises per session. Thus, if there are two groups performing the leg press, the bench press, and a bicep curl, one group doing 3 sets of 80% 1RM to failure on each exercise, and another group doing the same but with 40% 1RM, the huge metabolic fatigue induced by the latter group is less likely to negatively affect subsequent exercises like it would in a real-world leg day (like the example I gave in number 1).
3. Training to failure in a lab is not the same as in a gym: I’ve conducted training studies, and I can tell you that failure means exactly that when it comes to a study. You do the exercise while a group of researchers spot you and verbally motivate you to complete repetitions until you literally attempt a rep you cannot complete. In the gym, you are most likely going to stop when it feels like failure, versus being forced to go to failure. Subsequently, the vast majority of analyses on low-load training are examining training programs where true failure is achieved on each set.
4. Gauging distance from failure is harder with high-rep sets: If the standard way to train to failure in the real world is to simply do reps until you don’t you think you can do any more, we have to consider that people aren’t good at gauging distance from failure when they have to do a lot of reps (6). It’s relatively easy to tell when you are near true failure when you are only doing a total of 4-8 reps with a pretty heavy weight; when you simply cannot produce enough force to keep the weight moving, you aren’t in a ton of pain or out of breath, in most cases. However, the haze of cardiovascular fatigue and local pain on something like a squat when doing an AMRAP with 70% of 1RM (which allows ~10-20 reps depending on the individual) means you will underestimate how many repetitions you have left when further from failure, until you are really close to it (a true 9 RPE, or 1 repetition remaining prior to failure). When you think you are at a 7 RPE (just 3 repetitions remaining prior to failure) on an AMRAP with 70% 1RM on squats, there is a strong possibility you might actually have ~6 repetitions remaining, not 3 (6).
All in all, we need to consider the implications of the above and how they impact low-load training for hypertrophy in the real world. Let’s say your current approach is a four-day upper/lower split including a mix of compound and isolation movements in the 4-15 rep range, with the final sets for each muscle group approaching and sometimes reaching failure. This is arguably an “evidence-based approach” that would be appropriate for your average but serious hypertrophy enthusiast (7). Now let’s say that based on the emerging research on low-load training, you decide to change all your movements to the 15-25 rep range because you enjoy getting a pump more than lifting heavy, and you experience some joint stress when lifting moderate to heavy loads. At face value, this is a reasonable thing to do.
However, based on what we know, you’d likely need to take all of your sets to or near failure in order to put this program on equal footing with what you were doing previously; we’ll say an 8-10 RPE or 0-2 repetitions remaining after a set’s completion. Especially on leg day, that is going to cause some issues. The subsequent fatigue, pain, motivational drain, and GI distress from just your first compound movement on leg day is likely going to force you to reduce load substantially and/or increase rest periods substantially, just to complete your training sessions. Additionally, I’m skeptical that you’d reach true 8-10 RPEs on all your sets. Or rather, you may reach these perceived exertion values, but it may be due to pain inhibition and perceptual fatigue, rather than true muscular failure, which theoretically might not result in the same level of mechanical tension at the fiber level.
If you do decide to incorporate high-repetition, low-load training to or near failure in your program, that’s absolutely fine. However, you need to be aware of the potential practical concerns that may result in your real-world results not matching the findings in research. A simple solution I’d probably recommend is keeping your compound movements – especially lower body, free-weight compounds – in the moderate-load, moderate-repetition zone, while also staying a bit shy of failure. Doing sets of 6-8 reps between a 7-9 RPE (1-3 repetitions short of failure) is going to land in the ~75-85% of 1RM range for most people, and the vast majority of that volume will be “effective” for producing hypertrophy. Then, when you get to your isolation exercises and machine movements, you won’t be thrashed, and you can do your high-repetition training with fewer potential confounding factors.
References
- Schoenfeld, B.J., et al., Strength and hypertrophy adaptations between low- versus high-load resistance training: A systematic review and meta-analysis. J Strength Cond Res, 2017.
- Ogasawara, R., et al., Low-load bench press training to fatigue results in muscle hypertrophy similar to high-load bench press training. International Journal of Clinical Medicine, 2013. 4: p. 114.
- Pinto, R., et al., Relationship between workload and neuromuscular activity in the bench press exercise. Medicina Sportiva, 2013. 17(1): p. 1-6.
- Vigotsky, A.D., et al., Effects of load on good morning kinematics and EMG activity. PeerJ, 2015. 3.
- Burd, N.A., et al., Bigger weights may not beget bigger muscles: evidence from acute muscle protein synthetic responses after resistance exercise. Appl Physiol Nutr Metab, 2012. 37(3): p. 551-4.
- Perlmutter, J.H., et al., Total Repetitions Per Set Effects Repetitions in Reserve-based Rating of Perceived Exertion Accuracy: 3648 Board #95 June 3 8: 00 AM – 9: 30 AM. Medicine & Science in Sports & Exercise, 2017. 49(5S): p. 1043.
- Helms, E.R., et al., Recommendations for natural bodybuilding contest preparation: resistance and cardiovascular training. Journal of Sports Medicine and Physical Fitness, 2015. 55(3): p. 164-78.
Read Next
- The “Hypertrophy Range” – Fact or Fiction?
- Can We Predict Muscle Growth?
- The New Approach to Training Volume
Joseph says
Hi Eric / Greg,
I’ve been reading the content on this site / 3DMJ for some time and was wondering if either of you might have any thoughts on how a rep guideline like this:
“Doing sets of 6-8 reps between a 7-9 RPE (1-3 repetitions short of failure) is going to land in the ~75-85% of 1RM range for most people,”
would work for weighted chin / pull ups. Or in general – if either of you plan to do a tapering / peaking / loading guide to this movement! I know it probably isn’t popular enough to be researched or to be studied by many, but on the off chance that you’ve encountered a paper or have some knowledge about it..
If not, cheers anyway and thanks for the piece 🙂
Greg Nuckols says
I think that’s a solid recommendation. The only issues (and I’m sure you’re aware of this) are that you need to include your bodyweight into figuring out percents, and that momentum from your lower body can skew things significantly.
Joseph says
Yep! I weigh 61 kg (so about 135 pounds), and when I’m doing 3-5 sets of 6-8 reps at a 8-9 RPE the weight that I’m using is either an extra 21kg ( which adds up to 73% of my 1RM ) or 26kg (77%).
So I was asking because I was honestly astonished at how precise the carryover was, and I was wondering whether it was just personal to me. Thanks for the reply Greg, appreciate it. Hope you’re doing good with the blueberries too, can’t agree more on how delicious those are!
Kevin says
I definitely agree with your solution in the final paragraph. I’ve had the best results in 15 years of lifting over the last two years and anecdotally speaking it’s due to incorporating more high-rep, low-load sets into my workout. Going down this path was the result of injury, PT and injections, but I’ve liked it so much I’ve stuck with it. Moderate weight for moderate reps on the compounds, then high reps and low load for everything after that. I’m growing again, have remained injury free and seem to take much less of a CNS hit than I did while lifting heavy.
Yon says
Probably the best account on this topic I have read. Thanks Eric and Greg!
Markus Keller says
I like this article, but I expected it much earlier.
It might be 1 year ago that Stuart Phillips placed extensive ads I noticed on German Facebook. It was about his revisited work on light weights that empossible hypertrophy like heavy weights do.
Brad Schoenfeld shared this and there was much applause on this. Then followed B. Schoenfelds generally confirming meta analysis on this subject. And again there was applause.
But the obvious truth is: ” In simple terms, there is a reason 20-rep sets of squats are called “widow makers.”
I commented exactly this argument under Mr. Phillips post. Moreover, I calculated the estimated different workloads for light/heavy weights 30/80 RPM and concluded: Hypertrophy with light weights is highly inefficient and not a realistic option for daily sports practice.
No one saw Stuart Phillips post, no one saw my comments and found it interesting to answer?
Sorry, I don’t believe. I think this subject provides strong evidence that some of the scientific US-stars in the scene (and their followers?!) have a problem with objective thinking. Maybe some of them are more keen on being prominent than to be open-minded and self-critical.
Greg Nuckols says
To counter that, though, if you’re doing sets of 20, you don’t have to do squats. You could definitely do curls for sets of 20 vs. sets of 8, and sets of 20 knee extensions are probably even preferable to sets of 8. I’m honestly not sure where Stu stands on the topic of feasibility, but I know Brad has made a very similar argument to the one in this argument (talking about how many of his subjects threw up after doing sets of 30 squats).
Troy says
Hey Greg, great article and thanks for posting it and have Eric write it.
Just a follow-up on this, do you think – given both of your expertise and public following – it’s possible for yourself or Eric to get in touch with Stu about this practice/premise concept? He’s clearly a very knowledgeable guy in this area and I too would be interested to hear what he has to say when considering the specific form of lower leg exercises both Markus and Eric outline above.
Thanks for the great content you put out, it’s much appreciated mate.
Greg Nuckols says
When I’ve seen Stu talk about it, he’s specifically framed it in the context of being really useful for people who can’t tolerate heavy loading (i.e. the elderly, people with injuries, etc.). I haven’t seen him argue that low load is the best way to train for healthy young people, though.
Matt says
Are there interesting implications to post-surgery atrophy prevention here? If it’s possible to create hypertrophy with extremely low loads, would one be able to do a better job of staving off muscle-loss (and possibly recover faster) by pushing to failure under no to light loads?
Greg Nuckols says
That’s one of the proposed applications of low load training (and low load training with BFR). It probably depends on the type of injury you’re dealing with, though. If it’s something characterized by inflammation/neovascularization, low load may not be the best option (heavy, slow speed training may be a better option). If it’s something that’s load-limited (i.e. early ACL rehab) low load can be a great option. standard disclaimer – always talk to a physical therapist about specific issues
Martin says
Hi Greg,
do you know when measurements of muscle hypertrophy are usually made? I can’t acess fulltext of the first review/meta-analysys from Brad. The second study says 3-4 days after the last session.
I’d like to know this to have at least a hint about the “pump” effect on the measurements. I don’t know how many days a “pump” lasts (also don’t know if a pump from sets of 30RM lasts the same as sets of 15RM). I found a comment from you on an article of yours (https://www.strongerbyscience.com/the-new-approach-t
o-training-volume/) saying that a pump lasts 1-2 days; do you still believe this (the article is from 2 years ago)?
If a pump lasts only 2 days tops, then 3-4 days after the last session is perfectly reasonable to eliminate the pump’s effect on hypertrophy.
thank you.
Greg Nuckols says
It depends on training status. But yeah, for the most part, it’s gone in 2-3 days for untrained people, and 1-2 days for trained people. MOST studies take hypertrophy measurements at least 3 days after the last training session for that reason
Martin says
That’s great. Thank you!
Kyle says
I wonder what differences “widowmaker” squat sets (and high rep sets to failure in general) have on CNS fatigue post-workout and neural drive during the workout compared to the traditionally taught 8-12 rep hypertrophy range. It seems like high rep compound movements like squats or trap bar deadlifts would cause a lot more central fatigue. What do you think?
Greg Nuckols says
There was a study several months back showing that sets of 10 caused more fatigue than sets of 3 (with loads that should have been similarly challenging; https://www.ncbi.nlm.nih.gov/pubmed/28447186), so that very well could extend to higher rep sets as well. However, I doubt it’s CNS fatigue (https://bayesianbodybuilding.com/cns-fatigue/)
Henrik says
“Doing sets of 6-8 reps between a 7-9 RPE (1-3 repetitions short of failure) is going to land in the ~75-85% of 1RM range for most people”
This made me stop and think a bit. If I were to do 6 reps at 80% of my 1RM, especially in the squat and deadlift, I’d be wheezing for breath, and I would most likely be at a 9.5 RPE
First off: the obvious answer is to work on cardio. But I have chronic bronchitis, and while I do perform better when using my prescribed inhaler, I’m wondering if there has been any research into the ways in which a condition such as mine affects and limits potential, or possible workarounds.
Also, I do realize that none of this is meant to be taken as medical advice and I will for sure consult with my medical professional for advice pertaining to my particular circumstance.
But the question stands regarding general research.
Greg Nuckols says
My general hunch is that it probably doesn’t matter TOO much. I basically think that as long as you’re challenging your muscles adequately with a heavy enough load, it doesn’t matter whether that challenge is 6 reps at 80% or 10 reps at 80% (assuming 6 reps is just as challenging for you as 10 reps would be to someone else). Simplifying massively, I think the two main things your muscles “sense” are tension and fatigue. If tension is the same, and it takes fewer reps to generate fatigue (but fatigue is still the same), I think you’re probably fine.
Derek says
Hi Greg,
Alothough this is a good article overall, I have a few issues with it. Firstly it labours under the presumption that you need to be using compound exercises to maximize hypertrophy when that isn’t true. In fact taking into account all the factors that optimise the productivity of an exercise like alignment, resistance curve vs strength curve, exertion, safety etc. more often than not isolation exercises out perform compound exercises. For example: a shoulder routine that consists of Standing Barbell Shoulder Presses for 5×5 with around 80% of 1RM, causes quite a lot of general fatigue due to the amount of peripheral musculature involved & is not that great of an exercise for targeting the side/rear deltoid heads. Whereas if I perform a tri set of front, side and lateral raises (with a cable or Dumbbells) for 5 sets of around 15-20 to a point of momentary fatigue, I would be creating a high amount of tension & fatigue on target musculature, whilst minimalizing the amount of overall exertion experienced, (can be performed with shorter rest periods to maximize time in the gym). So it creates a more effective and direct growth stimulus for the target musculature, with less overall exertion whilst allowing for the performance of a higher recoverable load.
(Part 1 of 2…)
Greg Nuckols says
It doesn’t so much assume that compound exercises are inherently superior, but rather that MOST people will be doing a lot of compound exercises since they’re generally a more efficient way to train (more muscles trained in less time).
Derek says
(Part 2)
The same when we talk about leg/more specifically Quad work. If I perform a set of Heavy Backwards Prowler/Sled Drags with a strap around my waist, with a resistance that causes me to hit a point of momentary fatigue at around 40-60 metres, I have better stimulation of the Quads (due to the fact the operating lever of the quads/the Shin is actually perpendicular with gravity at the start of each rep, something not achieved with Squats) and I have minimized peripheral fatigue as I have taken out all the secondary musculature that is used during Barbell Back Squats (a lot of which are not necessarily going to receive sufficient stimulus for growth from squatting anyway). I also disagree with the statement that at a lower weight you have to go to total failure to maximise the productivity of a working set, as by the time rep speed has slowed down significantly (usually within a couple of reps of absolute failure) you have already reached a point of momentary muscular fatigue and the set has peaked in it’s ability to stimulate growth. This is the exact way that I train & not going to a point of actual concentric failure has never harmed my ability to progress my lifts.
Sorry about the 2 part Essay, it’s just that there are certain assumptions in this article that I wanted to raise.
David says
Hey guys,
Based on these realities, how do you feel about traditional moderate loads on compounds and higher rep rest-pause sets for isolation movements?
Greg Nuckols says
I think that’s a good way to go about it
Yon says
Hi Greg,
I was wondering what are your thoughts on ‘rest-pause’ training for hypertrophy. If ‘going to [or close to] failure’ is indeed the key signal that triggers hypertrophic adaptations (such that the last few reps in the set are the ones that really count), then would taking a set to failure, resting a 10-20 seconds, and then resuming the set until failure is reached again effectively count as two sets, from a hypertrophy standpoint? In other words, could one cut workout time significantly by doing just a small handful of rest-pause sets, as opposed to completing many individual sets wherein the initial reps are not going to fatigue the muscle? Thanks!
Greg Nuckols says
Possibly, though I somewhat doubt it. In healthy, young populations, longer rest intervals seem to be better for hypertrophy
Yon says
Thanks for the reply Greg. I see your point, though I think more studies on this topic are needed- particularly regarding so-called ‘effective’ reps.
A somewhat related question, if I may:
What happens if I’m in the middle of a cutting phase and switch from a low rep (5-7 reps) training protocol (which I have used while bulking) to a high rep (15-20 reps) protocol? Conventional bro wisdom is that taking ‘weight off the bar’ (i.e., reducing mechanical tension) while in a caloric deficit is a sure recipe for losing both strength and hard-earned muscle. However, the research findings you discuss suggest that this muscle loss would actually not occur, since both low and high rep protocols can yield the same hypertrophy- and thus (presumably) preserve muscle equivalently. What are your thoughts on this issue?
Many thanks in advance for your time and insight!
Greg Nuckols says
We don’t have any research on that specifically, but my hunch is that both approaches are basically interchangeable (for building/retaining muscle; heavier training will be better for strength).
Kelly Hardiman says
Thanks Eric. My question involves tempo. If I’m going to failure at 75% 1rm my tempo is even until I get to 12 to 15 completed. Then if I pause and breathe (rest) at the top I can grind a few more out before failure as opposed to failing sooner if I keep the same tempo. Are they both true failure?
Eric Helms says
Kelly, that’s probably part of the reason it’s harder to tell distance to failure on squats in the RPE studies we did, small deviations in time interval between sets changes as you need to get more air in. Overall, I’m not a huge fan of doing high rep lower body compounds for this reason, because it is a little harder to compare between sets where inter-rep rest intervals differ