The idea of repetition ranges is pretty old, dating back at least to the ’50s. It’s the concept that training with certain weights and therefore repetitions elicits different adaptations like strength, muscle building and endurance. And on the first glance this makes perfect sense, as you get better at what you train. But if you followed the fitness industry for some time, you find conflicting ideas of what makes muscle grow the fastest. So grab a protein shake, put on the “Conan” soundtrack and let’s have a closer look.
As I mentioned above, you can find a wild variety of recommendations how to grow muscle faster. From the “just lift heavy, your body will be forced to grow” camp to the “sets of twenty make everyone grow” cultists, you can find success and failure stories everywhere. But why do we find such conflicting evidence?
What makes you grow
First of all, exercise science doesn’t even know exactly what makes muscle grow. For now we assume that muscle growth is driven by mechanical tension (the weight you move) and metabolic stress (metabolites accumulating during exercise). Those two factors are in a constant tug of war: the more weight you move, the less repetitions you are able to do and the less metabolic stress you induce. If you use less weight, you do more reps, induce more metabolic stress but achieve less mechanical tension.
This alone could be the reason why you find different rep range recommendations! We are all a little different and it is quite possible that there are people who thrive on sets of twenty. And for every “sets of twenty guy” out there, you will find one who gets huge with sets of five. The middle ground of 6-15 reps, which is traditionally known as the hypertrophy range, is probably just a good recommendations for the “average Joe” as it is a good compromise of mechanical load and metabolic stress.
If you look at the differences you find in scientific literature about using different rep ranges to build muscle, you will be pretty disappointed, as there isn’t much to see! The isn’t any good evidence that you have to train in a certain rep range to maximise muscle growth:

The good old hypertrophy range returns
Well, if there isn’t a hypertrophy range that maximises gains, is it even important what we do in the gym? Or on the other hand: Why should you even worry about programing different loads? You could do heavy sets for every exercise and be fine, right?
Not so fast, let’s look at this closer. One advantage of using heavier weights is that you get stronger, which could lead to more gains in the long run as you increase volume by lifting more weight, which is great. But training heavy can really beat you up leading to injury or “just” feeling fried after a few sets. Feeling crappy after your first working set of deadlifts will limit your performance for the rest of your training session, leading to less volume moved and less muscle built.
So you could just do really high reps, never get injured and keep growing forever, right? But consider doing squats for twenty reps. Most people won’t be able to stimulate their quads enough with those high rep squats because they won’t be able to catch their breath. As you can imagine, having to rerack your weight because your vision blurs and you start fainting, isn’t optimal for muscle growth (and it’s not optimal for fun either).
That’s where the good old hypertrophy range comes back into play. The 6-15 range is just a time tested recommendation thats allows most people to move a good amount of weight for a good amount of repetitions, using almost any exercise you can imagine. Is it optimal for everyone? No. Is it a good place to start? Yes!
Make it your own
If you read this blog regulary, you know that I am a big fan of individualization. You have to find out to what rep range you respond best to. You can start in the traditional hypertrophy range of 6-15 reps and then start experimenting. But keep this in mind:
- Heavier weights are best used for compound movements.
- Lighter weights are best used for isolation movements and most machines.
- Dumbbell loaded exercises can get really clunky if used with heavy weights, so use medium to high repetitions.
- Exercises with a high demand for stability are best used for medium reps (8-15) to keep them save and effective.
Try to answer these questions: “What allows me to get in the most high quality sets during each session?” “What exercise is best for me to hit the target muscle for the desired amount of reps?” After you found your personal hypertrophy range, don’t be afraid to occasionally train other rep ranges, as those might yield advantages that are not visible in the first place.
It’s important to use rep ranges across the spectrum. Don’t neglect lower and higher rep work. – Greg Nuckols
I hope I could help you find the answer to the age old question: “How much should I lift?” If you need help with your training plan, don’t be shy, let’s get in touch and optimize your training routine!
I am also courious to here your experience! What works best for you? Do you have a favourite rep range? Tell me in the comments!
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