The Best Rep Range for Muscle Growth

For me, sometimes it’s more important to perform well in training and know that I am improving rather than scoring in a game. It’s doing the hard work, day in, day out.
––Marcus Rashford

​If you’ve ever lifted weights before, I’m sure you’ve come across repetition ranges, such as 6-12 reps.
 
In a well-structured training program, these ranges won’t be assigned at random.
 
In fact, by selecting an appropriate range for each exercise, you can make your workouts more effective to achieve your fitness goals.
 
This article will focus on how to choose the best rep range to maximise muscle growth, but you’ll pick up on some fundamental concepts to improve strength and endurance, too.
 
Now that I’ve got your attention, let’s make some brain gains.

What does each rep range do?
 
These are the three most common rep ranges and their most popular use:
 

• The low range (1-5 reps), typically employed to increase strength
• The medium range (6-12 reps), also known as “the hypertrophy range”, usually recommended for muscle growth
• The high range (15-20+ reps) for muscular endurance

 
For decades, it was a shared belief among coaches, lifters, and researchers that each rep range can only accomplish one goal. For example, you can’t build muscle doing 15-20+ reps.
 
We now understand that these ranges aren’t separate. Instead, they form a continuum: the repetition continuum. In other words, you can build muscle, strength, and endurance within a larger spectrum of reps, but some sections of this continuum can be more advantageous for each goal than others.
 
If that’s the case, what should you take into account when picking your rep range for muscle growth?
 
Can you build muscle doing any number of reps?
 
Yes… but not quite. Allow me to explain.
 
To induce hypertrophy – the physiological process resulting in an increase in muscle mass – three fundamental conditions need to be in place:
 

1. During a set, you need to generate enough mechanical tension, which is the tension muscle fibres perceive as a result of having an external or internal force applied to them. This seems to be the primary driver of hypertrophy.
2. Over a certain period of time, you need to accumulate enough volume, which can be quantified as the number of challenging sets performed to train a certain muscle.
3. To be challenging enough to contribute to your total set volume, an individual set needs to be taken to failure or at least a few reps shy of failure. Proximity to failure is your intensity of effort.

 
Research shows that, if you take each set to failure, you can achieve all three conditions when performing any number of reps from 5 to 35 per set on average.
 
Outside of this rep range, at least one of the three conditions becomes more difficult to accomplish, which makes both very low ranges (1-5 reps) and very high ranges (35+ reps) less efficient to gain muscle.
 
For example, when doing sets of less than 5 reps, you may need more total sets in order to achieve the same degree of muscle growth as when doing sets of more than 5 reps.
 
In this study, for instance, they compared a group of subjects performing 3 sets of 10 reps to failure per exercise to a group performing 7 sets of 3 reps to failure per exercise.
 
There was no significant difference in muscle growth between the two conditions… but the workout with 7 sets of 3 reps per exercise took over an hour compared to 17 minutes for the workout with 3 sets of 10!
 
Furthermore, the subjects doing 7 sets of 3 reps reported more mental and physical fatigue after their sessions. Lastly, two of the subjects had to drop out of the study due to injuries, whereas nobody in the group doing 3 sets of 10 encountered such issues.
 
On the other hand, there seems to be a theoretical minimum load you need to apply to your muscle fibres to induce them to grow, although we don’t yet know what this theoretical load threshold is. Therefore, it’s probably a good idea to cap your reps at 30-35 max.
 
Moreover, if you do choose to do that many reps, it may be better for muscle growth to ensure that you’re taking your sets to complete failure. The problem is that training to failure all the time may not be safe or even beneficial, as I’ll cover later in this article.
 
So, in theory, you could build at least some muscle doing less than 5 reps or more than 35, but, in practice, you’ll likely get the most bang for your buck within this range.
 
What other considerations should you make when choosing your rep ranges?
 
When assigning a rep range to a certain exercise in a client’s training program, I use the following criteria:
 

1. The exercise itself
2. Intensity of effort
3. Time efficiency
4. Indirect ways to benefit hypertrophy
5. Enjoyment

 
1. The exercise itself
 
Not all rep ranges are suited to all exercises.
 
In general, I wouldn’t program more than 12 reps on a free-weight compound lift like the barbell squat.
 
Due to the complexity of the exercise, technique is likely to break down past a certain number of reps. This not only increases your injury risk, but it can also compromise your gains.
 
The reason is that, when your technique changes to a noticeable extent, it’s because your body is trying to shift the load to less fatigued muscles in order to continue completing the movement.
 
For example, if your hips start shooting backwards on a barbell squat, it’s because you’re recruiting your glutes to a greater degree to compensate for the rising fatigue in your quads. However, if your goal is to train your quads, that can be a problem.
 
A machine-based compound exercise like the leg press, which is less technical and recruits fewer muscles to begin with, is likely a more appropriate choice for higher-rep sets.
 
On the other hand, I don’t often program less than 10 reps for isolation lifts like bicep curls.
 
This is because smaller muscles are trained indirectly with compound lifts. For instance, the biceps are recruited when performing any pulling movements like rows and lat pull-downs.
 
As I mentioned, I tend to favour lower-rep sets for compound exercises, so including higher-rep sets for isolation lifts can provide a wider variety of hypertrophic stimuli to these smaller muscles.
 
2. Intensity of effort
 
Taking every set to failure is a foolproof way to ensure that your intensity of effort is high enough to induce hypertrophy, but there are drawbacks to training to failure all the time.
 
For one, it’s riskier, especially on free-weight compound lifts.
 
Moreover, it usually generates more fatigue than staying a few reps shy of failure.
 
Lastly, it may be foolproof, but it’s neither the only way to induce hypertrophy nor the best.
 
In fact, research shows that leaving three to four reps “in reserve” before hitting failure is not only enough to build muscle, but also less fatiguing. If you’re less fatigued, you may also be able to recover from more volume, which in turn may stimulate more hypertrophy. For a deeper dive into the pros and cons of failure training, check out this article.
 
However, studies also suggest that we tend to be more accurate in estimating reps in reserve when performing fewer repetitions per set.
 
So, with sets of 5-10 reps, I usually suggest to leave between four and one rep in reserve, with the occasional set taken to failure when safe and appropriate. With sets of more than 12-15 reps, I recommend to leave no more than one or two in reserve to account for the potential lower accuracy in estimating proximity to failure.
 
3. Time efficiency
 
Very high-rep sets of over 20 reps and very low-rep sets of 5 or less can take a long time for different reasons:
 

• It takes at least one to two minutes to complete 20+ reps.
• After a heavy set of 5 reps or less, you’ll likely need at least two to three minutes’ rest before you’re recovered enough for the next one.

 
Most of my clients are busy professionals, so I tend to focus on the 6-12 rep range to make the most gains in the most time-efficient manner.
 
4. Indirect ways to benefit hypertrophy
 
Should you never train for strength and muscular endurance if all you want is muscle growth?
 
You could, but you’d potentially miss out on some of the indirect benefits that these two training adaptations can provide to your hypertrophy goal:
 

• If you get stronger, you can lift heavier loads for the same number of reps, which is one way of increasing the force applied to your muscle fibres and thus the mechanical tension generated within a set.
• If you increase your endurance, you can recover better from a higher amount of challenging sets, which increases the total volume you can use to target a muscle or muscle group.

 
There are several ways to include lower- and higher-rep sets in your training to get some of these benefits. For example, you could do a couple of sets under 5 reps or above 20 in each session, or you could dedicate an entire training phase (three to six weeks) to either muscular strength or muscular endurance before returning to your usual hypertrophy training.
 
5. Enjoyment
 
Sticking to a program is a lot easier when you enjoy it, so I suggest you choose rep ranges that you like, that feel most comfortable and least aggravating for your joints, and that best suit your circumstances. You may discover that different exercises require different ranges to tick all these boxes.
 
In addition, you can experiment with the criteria I’ve described, and find a “formula” of exercises and rep ranges that enables you to get the best results you can.
 
For instance, if you love the 6-12 rep range, chances are you’ve never tried a “widow maker” (a set of 20+ reps on the leg press). Give it a go the next time you hit the gym.
 
You’ll curse me during the set, but thank me later, when the quad pump gets real.
 
Practical Takeaways
 

• You can grow muscle within a wide spectrum of reps (5 to 35) as long as you’re taking each set close enough to failure.
• When choosing the best rep range for an exercise, consider the exercise itself, the intensity of effort, how much time you have, the benefits of increasing strength and endurance for hypertrophy, and your own enjoyment.

 
Thanks for reading. May you make the best gains.
 
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