When you lift a weight, how many times should you lift it? Supposedly, there’s a correct “rep range” to use to build strength, and a different rep range to build muscle size, or endurance, or to “tone.” But how much of the oft-repeated wisdom is true? Not as much as you’d think.
What are reps and sets?
Just so we’re on the same page here: if you pick up a dumbbell and do eight curls before putting the weight down, you have just done one set of eight reps. (Rep is short for repetition.)
Typically a workout will call for several sets of each exercise, separated by a rest period or by another exercise. Typical schemes include three sets of 10, four sets of eight to 12, or five sets of five. These are often written in the format [sets]x[reps], so 5 x 5 would be five sets of five reps each, and 3 x 10 would be three sets of 10.
There are many factors you might consider (or that an experienced trainer might include when writing your program) when deciding how many reps you should do, but often people try to stick with the “rep range” that they are told makes sense with their goals.
What are the traditional rep ranges?
Here’s what you’ll hear from many trainers, influencers, and online resources. Beware that you need to take these with a grain of salt, and I’ll explain why in a minute:
Smaller numbers of reps, like one to five, are said to be for strength.
Medium numbers, like six to 12, are said to be for building muscle size.
If you’re a woman and want to “tone,” you may be told that eight to 12, or maybe 10 to 15, will give you definition while keeping your muscles from growing too much.
A rep range of 15 or more is usually held to be for muscular endurance.
The exact numbers will vary depending on who you ask, but no matter how you slice it, something isn’t adding up. If you do 10 reps, are you building muscle size, or are you keeping your muscles “toned”? It can’t be both—unless 10 can work for either goal, in which case the number of reps isn’t what determines the outcome. (Hmm…)
It’s also wrong to think that strength and muscle growth are completely separate from each other, with different ways to build each. So let’s go over some practical advice for deciding what rep ranges you should actually work with.
Strength and muscle size don’t (always) require different training
Beginners in the gym often spend a lot of effort figuring out the “optimal” routine to meet their goals. But as I’ve said before, optimal is optional. Getting the details right is not nearly as important as getting the big picture right.
And the big picture for most beginner and intermediate lifters is that pretty much everything will build both strength and muscle size. You can lift in the “strength” range and still build muscle. You can lift in the “size” range and find yourself gaining strength.
You can read a deep dive on this idea here. The author, powerlifter and coach Greg Nuckols, does conclude that lower numbers of reps (like 1-5) have a bias toward strength, and higher reps (15+) have a bias toward muscular endurance.
But for growing muscles in size, just about anything works. He summarizes: “The ‘hypertrophy [size gaining] range’ of roughly six to 15 reps per set may produce slightly better results per unit of time invested than low rep and high rep work. However, on the whole, the advantage you get from working in the hypertrophy range isn’t nearly as big as people seem to think; maybe a ~10-15% advantage per unit of effort invested at most.”
He recommends training in a variety of rep ranges if you want bigger or more defined muscles, rather than using the same narrow range every time. That’s pretty much the consensus among good trainers, anyway: most effective training programs have a mix of high and low rep exercises. That’s because each rep range has its pros and cons when it comes to particular exercises and purposes, not just a person’s overall goals.
When to use low reps (1-5)
This is traditionally the strength range, and to be fair, it is a good rep range to work on strength. Here, I’m using “strength” to mean increasing the amount of weight you can lift, even if you can only lift it once.
For strength
If you want to show off in front of your friends by benching more than them, or if you want to enter a weightlifting competition and place well, or if you want to achieve your first pullup, you want to work on strength.
This means you need to practice with heavy weights. A weight that you can lift 10 times in a row is going to be fairly light, relative to your ability, and it won’t teach your body everything it needs to know for a heavy lift. So you’ll need to work with low reps (at least sometimes!) if you’re aiming for a strength goal.
To learn technique
Low reps also help you to focus and avoid fatigue. You might get tired or sloppy by the 10th rep of a set, but that’s less likely to happen in a set of three. Olympic weightlifters typically do their tricky competition lifts in sets of just one to three.
Beginners who are learning a new exercise, like squats or barbell presses, may also want to work in this range. Do a few reps, take a break, then come back fresh.
For muscle size, alongside other rep ranges
Heavy weights put a lot of mechanical tension on your muscles, and they help you get stronger. These factors mean low-rep sets can still help your muscles to grow, even though they aren’t the traditional muscle-growth rep range. After all, the stronger you are, the heavier the weights you can handle—which means you can go even heavier in your moderate- and high-rep sets.
When to use moderate reps (6-12)
This is a good middle ground that will build strength and size, and will give you plenty of practice moving weight around. Pretty much everybody can benefit from working in this rep range, at least some of the time.
For strength and muscle size
This is the range that’s probably ideal for gaining muscle size, and it will help a lot in supporting your efforts to build strength.
Even athletes who focus on strength will include plenty of work in this rep range for the purpose of growing some extra muscle mass. After doing squats in sets of three, you might go and do sets of 10 on lunges or leg extensions or the leg press machine.
For beginners and for general fitness
While low reps are best for learning an exercise that is complicated or that is brand new to you, beginners are often recommended to work in a medium rep range as soon as they’re comfortable with it—and that makes a lot of sense.
Doing eight or 10 reps of the same exercise gives you plenty of practice (there are 30 reps in three sets of 10), without having to strain to handle a heavy weight that you haven’t mastered the technique for yet.
For “toning”
Toning isn’t a specific strength training goal, and that’s why it doesn’t have its own special rep range. Being “toned” is mostly just a look: it means you have some muscle definition while being relatively slim.
That’s why the same exercises that build muscle in people who want to “bulk” are also appropriate for people who want to “tone.” Or to put it another way: any resistance training that builds muscle will be appropriate for both goals.
So what makes a “bulky” body different from a “toned” one? Partly nutrition (the more you eat, the bigger your muscles can get) and partly just how long you’ve been training and how hard you’ve worked. It takes a lot of time to build a lot of muscle.
I might even say there’s a component of mindset: people who recognize how important muscle is for their health and for their fitness goals tend to see their new muscles as part of a healthy, fit look—not necessarily as “bulk.”
When to use higher reps (15+)
Traditionally this is described as the “muscular endurance” range, but that’s a misnomer. Higher reps aren’t great at building strength, and may not be your best option for building muscle size, so just about all they have left to offer is that they might help you do high numbers of reps.
For muscular endurance, alongside lower rep ranges
The thing is, if you want to build muscular endurance—say, you want to be able to do 100 pushups in a row—you will also benefit from using lower rep ranges to build strength. The stronger you are, the easier each pushup will be for you, and the longer you’ll be able to keep going.
Studies have found that you don’t need to stick to the 15+ rep range to build muscular endurance—the three-to-five and six-to-eight ranges may work even better than spending your training time on high reps.
If your ultimate goal is to do 100 pushups, I wouldn’t tell you to only do high-rep sets; those low-rep ones are useful too. But I’d still expect you to practice high reps for the skill, conditioning, and mental toughness that will be required to execute your goal.
For muscle size (and “toning”), if you only have light weights available
To do heavy or moderate reps, you need appropriate weights. So if you’re working with limited equipment, you may have no option but to make the best of what you’ve got.
Fortunately, research has found that muscles can still grow in size if you use light weights and high repetitions, so long as you take each set to failure. So if it takes 20 or even 30 reps to tire out your arms when doing bench press with a set of light dumbbells, that’s still workable.
If you’re able to do more than 30 reps, though, we’re starting to leave the realm of strength training and enter a territory that’s more like cardio. At that point, you should really look for harder exercises or find a way to get your hands on heavier dumbbells.
The bottom line: variety in rep ranges is good
Ultimately, you don’t need to decide on one rep range for all your training. You won’t see powerlifters only working in the strength range, or bodybuilders only working in the size range. The guy in your neighborhood who can do 25 pullups at the local park probably isn’t doing 25 of everything in his workout routine.
So when you go to the gym, you’ll probably want to use low reps for a strength-focused exercise or two, moderate reps for most of your other work, and occasionally some higher-rep work for variety or to make do with lighter equipment.