What’s The Best Rep Range For Muscle Growth?

8-12 reps means muscle growth. 1-5 reps means strength. 15+ reps means endurance. Or so goes bodybuilding lore as it’s been canonized by bros handing down knowledge to the next generation of bros. Oh and 6,7,13, or 14 reps were seemingly forbidden and rarely discussed. 

But along came research by Brad Schoenfeld, PhD and an assortment of other researchers and colleagues to challenge their own previously held beliefs on rep ranges for muscle hypertrophy(growth). The research upended the sacred lore and found you can build muscle effectively at any rep range as long as you meet a few conditions:

-Training volume is equated across the different rep ranges.

-You get within a few reps of failure.

-You use load at least 30% of your 1 rep max. (Curling pencils for near infinite reps won’t provide enough stimulus to approach failure or cause muscle growth, even if you spent a full day at it).

This research was groundbreaking, but robust and replicated. The science was settled and your chosen rep range no longer mattered. 

Or maybe not so fast. 

The science is sound but the practical implications of real world/non-lab settings add important context. Let’s explore further:

Low rep ranges for muscle hypertrophy:

Reps in the 1-5 rep range effectively stimulate muscle growth, as long as the load is heavy enough to approach failure. In case you haven’t noticed, weight that reaches failure between 1-5 reps is HEAVY, presenting the following challenges:

-Risk of failing on a rep.

-Difficulty getting enough mechanical tension from lower rep sets.

-Difficulty getting weights into position. (Think 3-5 rep max dumbbell shoulder press).

-Difficulty performing such heavy loads for isolations with strict form. Preacher curls for 4-5 reps to failure is generally a bad idea outside of arm wresting training. 

-Because of the relatively low reps per set, to equate for volume this load and rep range requires more sets. More sets means more time spent training to get the same volume. 

-Heavy sets to near failure require longer rest breaks than for sets of 8-12 or greater reps to adequately recover to perform the next set near full power. Usually in the 3-5 minute rest between sets range as opposed to 1-3 minutes with comparatively lighter weight. 

-Added sets plus longer rest makes this strategy time inefficient for muscle growth across multiple exercises in a workout, especially for those with limited windows to workout.

-Such heavy loads may place greater stress on joints and connective tissue. Multiplied across more sets, exercises, and workouts, this increased demand for recovery between workouts. Muscle tissue repairs faster than joint tissue because of the difference in blood flow. While muscles may feel recovered, connective tissue like tendons and ligaments may not repair at a pace that allows high frequency training for long periods of time without increased injury risk. 

Low rep ranges for strength:

1-5 reps to near failure is where strength progress thrives. While there is mechanical tension on muscle, this style of training optimizes for powerful and efficient recruitment of more muscle fibres by training a stronger neural impulse to recruit those fibres. 

Strength improvement allows for greater loading across all rep ranges, subjecting muscle to more mechanical tension. The investment in developing strength creates second order effects that promote muscle development. For beginners, doing almost any style of training will result in improved strength and muscle growth so they’re wisest focusing on skill vs heavy weights. Even for intermediate lifters strength and muscle are easily trained and improved concurrently. For advanced elite lifters, things start to diverge and more specialization is needed to make meaningful progress on either strength or muscle growth. At this point it’s better to choose to focus on one or the other vs continually trying to straddle the line of both. 

Underlying all this are 2 main ways we get stronger:

  1. We can bear more load through greater structural integrity, aka more muscle mass.
  2. We can better recruit current muscle mass with more powerful impulses from our nervous system. 
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Low rep high intensity training develops the latter pathway. But you still need muscular structure to be recruited and trained for more strength. Another way to think about improving neuromuscular strength is we get closer to being able to recruit 100% of our theoretical capability. Ever hear of grandmas lifting cars off of trapped children? Humans are capable of seemingly inhuman feats of strength in life or death situations. Fuelled by adrenaline, we can recruit all of our muscle fibres in a way we otherwise cannot voluntarily. Why can’t we? Because red lining our neuromuscular capability presents significant risk of connective tissue, bone, joint, and muscle injury. So our nervous system guards against and inhibits our ability to do this voluntarily. 

Strength training helps us improve our ability to recruit more muscle fibre more powerfully so we are getting closer to voluntarily recruiting everything we have. This is extremely important for performance in strength sports. Especially with a weight class component. For the rest of us, it’s probably wise to try to build as much muscle as possible for more structural integrity while also spending some time training neuromuscular strength. This is all a fancy way of explaining that we would be wise to spend time in a variety of rep ranges in our training. 

High rep ranges for muscle hypertrophy:

While classic era bodybuilders were some of the strongest athletes in the history of the sport, they didn’t spend much time training with low reps and high loads intending muscle growth. Many including the likes of Arnold, Franco Columbo, Ronnie Coleman, Stan Efferding, and Jonnie Jackson competed as both powerlifters(at least earlier in their careers) and bodybuilders, therefore spending time on heavier low rep training. They were known for experimentation with a wide array of rep ranges, training volumes, and intensities which meant training outside the classic 8-12 rep range. Some of this was likely motivated by the Arnold era popular, but misguided “muscle confusion” hypothesis, believing muscles needed to be “confused” by continually varying training stimulus. It often inadvertently worked by producing tons of mechanical tension and metabolic stress on muscle by doing sets of 20 or more to near failure. They often went well beyond failure with intense training methods like drop sets and rest pause. Dorian Yates helped to popularize using combinations of past failure tactics to extend his working sets to extremes. Tom Platz was notorious for sickness inducing high rep sets of squats, and he brandished a pair of the most impressive legs in bodybuilding history.

From a practical standpoint, when was the last time you did a set of 20-30 reps to absolute failure(or beyond with past failure techniques like drop sets)? It’s an agonizing way to train, though probably the sort of thing that separates the great from the merely good. And an approach almost no one would voluntarily submit themselves to for all of their training. Maybe some chest and shoulder pressing, curls, side laterals, tricep work, and calves. But few outside Platz and Dr. Mike Israetel are regularly lining up to hit regular sets of squats or leg press to rep counts of 20 or more to failure. 

Another problem with a ton of high rep training to failure is the neurological fatigue. We once believed the heavy load, low rep training was what disproportionately caused neurological fatigue, but research now points to high rep training as highly neurologically disruptive and fatiguing. Though developing the stamina to engage in and tolerate high intensity training is essential to getting the best results, consistently training beyond your ability to recover will lead to suboptimal results and increase risk of injury. 

There’s also a strong argument that if you can get within a few reps of failure at 8-15 or even 20 reps with a manageable weight, choosing lighter weight to get to 20-30+ reps on a set is unnecessarily time consuming and fatiguing. A lot of those reps aren’t really stimulative and could be characterized as junk volume. There may be some enhanced metabolic stress(pump) in the muscle but research more and more points to this being either substantially less important for muscle growth than mechanical tension, or just a concurrent byproduct of accumulating a lot of mechanical tension. 

No one is suggesting you always and only train with high load, low rep or low load, high rep, to failure for muscle growth. The research validates the use of more varied rep ranges in your training without sacrificing progress, In fact using more variation probably keeps training from getting stale, keeps your focus and motivation, and enhances overall training results. When you factor in the value in lighter load to near failure when battling sore joints and nagging injuries, this option may be a godsend for progress through injury. If anything, those who rarely venture outside the classic 8-12 rep range would benefit from more varied rep ranges as long as you’re training with high intensity. 

How to use a wider rep range for better progress:

If you’re doing the following, you’ll make great progress building muscle:

-Progressively add challenge week over week.

-Deload if needed(Deloads are overrated in most cases as most non-competitive lifters will have random life chaos create days off anyway).

-Train with high intensity by taking most working sets to within 1-2 reps of failure, and some sets beyond failure.

-Use good technique and emphasize negatives. (There is a great deal of argument about what constitutes “good technique” and if this plays a role in injury risk but at very least what we generally consider good technique will better recruit the targeted muscles and add up to more progress over time. Plus the increased injury risk from “poor form” is better understood as using too much load, intensity, and volume relative to your ability to recover and failing to control appropriate load through appropriate range of motion).

-Optimize protein at roughly 1 gram per lean pound of body mass per day(Some research points to needing less than this but it’s an easy target to aim for to ensure you’re more than covered).

-Eat in a modest calorie surplus that optimizes muscle growth but limits excess fat gain.

-Sleep 7-9 hours per night. 

-Take at least 1 day off from high intensity training for recovery per week.

If you then add in strategic use of different rep ranges, you unlock more potential for growth. 

-Add 1-2 sets of heavy near failure reps for large compound exercises like bench press, squats, Romanian deadlifts, and weighted chin-ups. Avoid starting a rep you aren’t 1000% sure you can finish unless you have an experienced spotter in place.

-Bias some of your big compound lifts and big accessories to a 6-8 rep range to near failure. Dumbbell bench is suitable for this, as are row variations, split squats, and virtually any machine exercise that trains compound exercise patterns. 

-Perform lots of work within the classic 8-12 rep range and push working sets to the bleeding edge of failure often but not always.

-Perform working sets of at least 1 exercise per workout into a 15-20 rep range or beyond, to near failure. Single joint isolations like shoulder raise variations, curls, tricep work, leg extensions, and any calf work are suitable. 

-1-2 times per workout take the last working set of an exercise beyond failure by incorporating drop sets, rest pause, or other past failure tactics. 

References:

  1. Schoenfeld, et al, “Effects of Low – vs. High – Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men” J Strength Cond Res, 2015
  2. Klemp, et al, “Volume-equated high-and low-repetition daily undulating programming strategies produce similar hypertrophy and strength adaptations” Appl Physiol Nutr Metab, 2016
  3. Schoenfeld, et al, “Strength and Hypertrophy Adaptations Between Low-vs High-Load Resistance Training: A Systematic Review and Meta-analysis” J Strength Cond Res., 2017
  4. Schoenfeld, et al, “Loading Recommendations for Muscle Strength Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum” Sports(Basel), 2021
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