In the workout world, every day a new series of ideas come out that disappears just as fast. One theory that is still on the table is regarding the “rep ranges”. For more than 50 years, people have been talking about how low reps are ideal for strength development, moderate reps are best for muscle building, and high reps are best for when you want to build strength endurance.

There are some beliefs that say that any muscle growth outside of the “hypertrophy range” will be close to zero. Others will say that you can still grow with low-rep or high-rep training, but the results won’t be as satisfying as the ones given by the “hypertrophy range.”

Before taking any conclusions, let’s just note that the assumptions about lower reps/higher weights building more strength and higher rep/lower weights building more strength endurance have been confirmed from many sources.

Gaining strength is better with heavy, low-rep training, but it can also be achieved with light weights/high reps and moderate weight/moderate reps. These being said, muscular endurance (how many times you can move a set load, regardless of your 1rm) can be built with a low rep and moderate rep training, but high rep training is mostly the only way to improve relative muscular endurance.

The purpose of this article is to discuss the middle are – hypertrophy range.

But before we actually start, let explain the terms so you won’t have any doubts while reading them:

  • Heavy or low-rep training means loads in excess of 85% of your 1rm, for sets of 5 reps or fewer.
  •  Moderate weights, moderate reps, and the hypertrophy zone represent the loads between 60-85% of your 1rm, for sets of 6-15 reps.
  • The light-weights or high reps represent the loads that are less than 60% of your 1rm, for sets of 15 reps or more.

Systematic View

The first thing you should understand is how the muscles grow. The main mechanisms of hypertrophy are mechanical tension and metabolic stress. They have an indirect relationship. As one grows, the other one decreases. So when you lift more weight you induce more tension, so metabolic stress is lower. Lift less, you cause more metabolic stress but the muscle tension is lower.

When reading this you’d expect training to be effective across a pretty broad range of parameters.

Is the hypertrophy range proved by science?

There are many studies made on groups training in the “hypertrophy range” of 6-15 reps per set. We will talk about:

  • A specific one that took into consideration the Hypertrophy Range vs. Study Averages.

The results showed that low reps out-performed the study means by 1% on average compared to moderate reps. On the other hand, moderate reps out-performed the study means by 1% on average compared to high reps. 

  • Another study was made on The “Hypertrophy Range” vs. High and Low Reps.

Of the 13 calculable effect sizes comparing low to moderate reps, three favored moderate reps, two favored low reps, and the other eight were ties. The normal effect size in the low rep measurements was 0.68, and the average effect size in the moderate rep measurements was 0.71.  These average effect sizes were not significantly different (p = 0.37). Of the 16 calculable effect sizes comparing high to moderate reps, nine favored moderate reps, three favored high reps, and the other four were ties. The common effect size in the high rep measurements was 0.75, and the average effect size in the moderate rep measurements was 1.08.

  • Percent Muscle Growth in Each Study

Most studies are comparing low reps to moderate reps. 33% of them prefer moderate reps, 33% of them prefer low reps. The others considered being a tie between them.

Another bunch of studies compared high reps to moderate reps. 36% preferred moderate reps, 42% of them favored high reps and the other offered a tie.

Adding all these studies together it appears that low reps caused measures of muscle size to increase by 11.91±5.70%, moderate reps caused measures of muscle size to increase by 10.63%.

The final bunch was made to compare high reps to moderate reps and it appears that the correlation is effectively nonexistent.

So is there a hypertrophy rep range?

Most probably, yes. But this doesn’t implicitly mean that everybody should train there. If you look at the case studies, you will notice that the hypertrophy range did better than both high reps or low reps. But in some cases, low reps or high reps had a small edge.

Most probably the fancy scientific terms made you confused so I will  try to make it easier and  explain what exactly you need to understand about the subject:

  • Hypertrophy range of 6-15 reps per set can produce better results per unit of time invested than low rep and high rep work. But the truth is that the advantage offered by working in the hypertrophy range isn’t nearly as big as people seem to think. It can offer approx. 10-15% advantage per unit of effort invested.
  • You can also grow when training with low reps and high reps. You will probably miss out on some growth if you confine yourself to a single rep range. Individual signaling pathways would habituate to a single stimulus faster than multiple signaling pathways would habituate to slightly different stimuli.
  • Single rep range is not for everyone. Some people and some exercises just seem to do better with higher reps or lower reps.

High-quality sets refer to those that employ exercises that are going to be restricted by the muscles in training, through the longest range of motion in a  safe form, taken within 2-3 reps of failure and performed when adequately recovered from your previous set.

Hard sets are different from person to person. For some,  heavy sets of 3-5 reps will make them feel worn out and the rest of their workout will suffer. For others, sets of 12-15+ will only have a metabolic effect. This is especially true when talking about squats and deadlifts, meaning they can’t get in much high-quality work after a couple of hard sets.

To make the best out of the hard sets from a session, you should stop after 2-3 reps shy of failure. A set to failure generally takes more out of you than a set stopped a bit earlier and puts a limit on how much more quality work you can handle.  Maximizing hard training set in a week depends on how you can recover between sessions and how your training week is structured.

This article is not about how to best structure your training week, but the idea is a simple one.

  • If you’re training a muscle or movement twice per week, then you should let at least 72 hours between the sessions.
  • If training a muscle or movement more than twice per week, be sure that you are well-rested when going into the hardest sessions, and intercalate harder sessions with easier ones so that you’re not accumulating too much fatigue.
  • If training one hard lift is going to interfere with another lift, you should try to do them in the same session so that you have time to recover before doing them again. Or you should try to put as much time as possible between your hardest session for one and your hardest session for the other.

So this is where hypertrophy rep range really comes from. In the 6-15 rep range, weights offer the possibility of a good technique, will not cheat the range of motion and will not create creaky joints. But the weights are still heavy enough, so you will still put tension on the muscle. And you are probably limited in each set by muscular fatigue rather than systemic anaerobic fatigue. So you won’t do so many reps to make you metabolically crushed after your first couple of sets.

There is no magic around the hypertrophy range. It works because you are able to do more hard training and this will produce better results. This means that you should find the rep range for each lift that allows you to get the most high-quality work in.

Let’s check some rep ranges that work for several key lifts:

  • Pull-ups. Make a set of 5-10. Pull-ups lend themselves to lower reps. Moreso, people tend to start adjusting range of motion with higher reps.
  • Rows. A set between 8-15. Sometimes, people mistake and go too heavy and turn rows into a hip hinging exercise more so than a lat exercise. Cheat rows are an effective accessory lift for improving your deadlift but don’t tend to be a great lat builder.
  • Squats and deadlifts. For squats sets of 3-8 tend to help people strengthen sports background. For newer lifters, a set of 5-10 will do the trick. It’s typically a bit lower for deadlifts than squats, because letting your technique slip as you fatigue is easier with deadlifts.
  • Unilateral lower body work. Sets of 8-15. The weight needs to be light enough so you can work the target muscles. This way you will also train the movement effectively instead of turning the exercise into a balancing act, but they also need to be heavy enough that metabolic fatigue within the set isn’t going to start making balance problematic toward the end of the set.
  • Dumbbell pressing. Sets of 8-15. When weights are too heavy, balance can become problematic. This means that you will waste a lot of energy just controlling the weight instead of training the muscles you’re trying to train.
  • Any sort of isolation lift or machine work. Sets of 8+. With isolation lifts, there is no problem regarding systemic metabolic fatigue. Going really heavy can irritate a lot of people’s tendons because you can work the individual muscle through a longer range of motion than you’d be able to with a compound lift. When it comes to machine work, low reps on machines doesn’t seem to work very well.
  • Barbell pressing. For the best results, do sets of 5-10. When the workout is too heavy or too often people’s elbows and shoulders will be beaten up. This is why a lot of people find that higher rep sets seem to be limited more by their anterior deltoids than their pecs, lateral deltoids, or triceps

However, all these are just part of a guideline. You need to start, and experiment to see what is the point where you get the most high-quality work. There are people who have better results with higher or lower reps. Try to get 60-70% of your work set in the rep range that you personally find works best for you. Do 15-20% of your sets with heavier weights/lower reps and the last part of the percentage work with lighter weights/higher reps.