The literature on building muscle has come quite a long way since I was first certified at the end of 2015. During my studies, I was taught that in order to build muscle, you had to lift moderate to heavy weights within 8-12 reps and anywhere from 3-5 sets. This seemed to be the magical number at which your muscles would suddenly grow. Anything other rep and set range would promote either muscular endurance or strength.
I also learned all of the various hormonal mechanisms at play that helped to contribute to increased muscle growth, which served to make sense of why you needed this magical rep and set range. Even so, conflicting evidence abounds. What about body builders? According to some literature, they don't even necessarily follow the above rep and set ranges, yet they still manage to build muscle.
Turns out the science behind muscle building doesn't have to be so complicated.
The set and rep range doesn't matter. Not even the weight you lift matters...to a certain extent. What matters, according to recent literature, is that you lift until near failure. So you can keep lifting two 5 lb. dumbbells until you can't lift anymore. But, of course, that would consume an unnecessary amount of time, particularly for people who are already accustomed to lifting heavy. So the best way to build muscle is to choose a set and rep range with a moderate amount of weights that allows you to use your time wisely. But what exactly are the mechanics behind building muscle?
According to the "Hypertrophy Range"--Fact or Fiction?" these two factors are mechanical tension and metabolic stress. Unfortunately, having both at the same time is unlikely. You can create a lot of mechanical stress by lifting a heavy weight, but you can't create as much metabolic stress because you can't do as many reps. To create more metabolic stress, you can lower the weight, but you also remove the mechanical tension. This sounds complicated, but it's really not.
You should conclude that in order to build muscle, a variety of sets and rep ranges should be used, ensuring that you take these reps to near failure. For example, on days I want to build muscle, I'll mix things up by adding in breakdown training: I start with a heavy weight, then keep decreasing until I just can't lift anymore. That heavy weight creates the necessary metabolic stress, and the continual lowering of the weight creates that necessary mechanical stress, even though the metabolic stress was removed.
Other days, I'll just do 3-5 sets of 8-12 reps, depending on what I think my body can handle. Breakdown training creates much more mechanical stress than simply lifting a single set of weights and then resting. (I advise you read the above linked article if you desire more detail.)
Another type of training I'll sometimes use is time-under-tension training. For example, if I'm doing seated rows, I'll hold the end range for 3 seconds before slowly lowering the weight stack for another 3 seconds. There are various combinations you can try. Some people go fast on the concentric part of the lift (the hard part) and then slowly lower on the eccentric part (the easy port).
This all seems complicated, but it really isn't once you start to put it into practice. If you're a beginner lifter, any stimulus will produce muscular growth. It is only when you begin to advance that you should consider other types of training in order to see continual improvements in muscular growth.
Now let's talk about lifting to near failure. You don't want to do this with exercises where the risk of injury is high, such as squats with a barbell. You can do this on lifts that have a low chance of injury, however, such as bicep curls. With the bigger lifts, you wan to lift until your technique begins to fall apart. Once that happens, you should stop lifting. After all, no one wants to be crushed by a barbell from taking that set to near failure.
Another rule of thumb is to use single-joint exercises, such as the bicep curl, for higher reps--anywhere between 8-15. With multi-joint exercises, anywhere from 3-8 reps for more experienced lifters and 5-10 for less experienced lifters is doable.
What about recovery time? Generally when it comes to muscle building, you want to rest anywhere from 60 seconds to 90 seconds between sets. Any less may make it difficult to to push out all the reps you want, and any more may remove the metabolic stress.
To conclude, testing a variety of rep ranges and sets to find what works for you is the best method to use.
ACE Certified Personal Trainer, NSCA Certified Strength and Conditioning Specialist, nutrition coach, young adult author, moody ballerina.
I help people perform without pain.
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The views expressed on this blog are entirely my own. Any advice I offer is not to be taken as medical advice. If you think you have contraindications to exercise, please see your physician before implementing any sample workout plans I present on this blog.
All images are either my own, from Canva, or Creative Commons