How Many Reps Are You Supposed to Do, Anyway?

For years, resistance training came with a pretty simple set of rules.

Want to build strength? Do 1 to 6 reps.

Want to build muscle? Do 8 to 12.

Want muscular endurance? Do 15 or more.

Simple. Neat. Easy to remember.

And like a lot of things in fitness, it's not exactly wrong. It's just a little more complicated than that.

Research over the past several years has shown us that you have considerably more flexibility with your rep ranges than we once believed. You can build muscle using relatively heavy weights, moderate weights, and even much lighter weights, provided the set is challenging enough. A 2017 systematic review and meta-analysis found similar muscle growth across a broad range of loading when sets were performed close to muscular failure, while heavier loads produced better improvements in maximal strength.

So naturally, somebody heard that and decided the answer was:

"Reps don't matter."

Nope.

That's not what the research says.

Reps still matter. They just matter differently depending on what you're trying to accomplish, what exercise you're performing, and how hard you're training.

Building muscle gives you more options

If your primary goal is building muscle, you don't necessarily have to live in the traditional 8-to-12 rep neighborhood.

Research comparing different loading ranges has consistently found that muscle growth can occur across a much broader spectrum when sets are performed with a high level of effort. A 2022 systematic review and meta-analysis found similar hypertrophy across very low, low, moderate, and high loads when volume was matched, while the heavier loads produced greater gains in dynamic strength.

That's good news because it gives you options.

But here's where things get interesting.

Just because you CAN build muscle with 20 or 30 reps doesn't mean that 30 reps is automatically the best choice for every exercise.

Consider a squat.

If you perform a set of 25 or 30 heavy-ish squats, what eventually causes you to stop? Your quads and glutes may certainly be working hard, but your cardiovascular system, ability to brace, breathing, balance, and overall fatigue can become major limiting factors.

In other words, your target muscles may not be the only reason the set ends.

That's one reason I generally prefer moderate rep ranges for bigger, more technically demanding compound movements.

For muscle building, somewhere around 5 to 10 reps is a practical sweet spot for many compound exercises.

Now compare that with something like a lateral raise, leg extension, triceps extension, or cable curl.

Doing 15 or 20 reps on these exercises can make perfect sense. The exercise is relatively simple, the technical demands are lower, and it's easier for the muscle you're actually trying to train to become the limiting factor.

That's a big part of how I think about rep ranges:

The muscle you're trying to train should ideally be the thing that makes you stop.

Higher reps aren't automatically “better” for your joints either

There's another reason I like having flexibility with rep ranges, especially when working with adults who have accumulated a few miles on the odometer.

Sometimes a heavier load simply doesn't feel good.

Maybe a particular joint doesn't tolerate heavy loading well. Maybe you're coming back from an injury.

Maybe an exercise feels significantly better with a lighter weight.

That doesn't mean you have to stop training the muscle.

You can reduce the load and increase the reps.

When lighter-load training is taken sufficiently close to muscular failure, research shows that it can still produce substantial muscle growth.

That's a valuable tool.

The goal isn't to prove how much weight you can move on every exercise. The goal is to create the training stimulus you need while managing fatigue, technique, recovery, and the realities of your body.

But strength is a different animal

This is where reps become much more important.

If your goal is to maximize strength, you need to spend at least some of your training time lifting heavier loads.

Why?

Because strength isn't just about having bigger muscles. It's also a skill.

Your nervous system has to learn how to produce force against heavy resistance while maintaining good technique.

Research consistently shows an advantage for higher-load training when the goal is improving maximal strength, even though muscle growth can be similar across different loading ranges.

That's why my general approach for strength is 3 to 6 reps, with most sets stopping short of failure.

And there's an important distinction here.

Training hard doesn't mean every set needs to become a death match.

If you're trying to build strength, repeatedly grinding every set until you physically cannot complete another rep can create a lot of fatigue and make it harder to maintain high-quality technique.

Most of the time, I prefer leaving 1 to 3 good reps in reserve.

You still work hard. You just don't turn every set into a personal argument with gravity.

There is a place for very heavy 1- or 2-rep efforts, particularly when testing strength or preparing for competition. But I wouldn't make those your everyday training prescription.

So how many reps should you actually do?

Here's the practical framework I use.

For building muscle with compound exercises, start around 5 to 10 reps.

For building muscle with isolation exercises, 10 to 20 reps is a great general range.

For strength development, spend most of your work around 3 to 6 reps, using challenging loads and keeping a few quality reps in reserve.

For testing strength, 1 to 2 reps can have a place, but they should be used much less frequently.

And if you're dealing with an injury or an exercise simply feels better with lighter weight, higher reps can be a very useful tool.

These aren't laws written in stone. They're starting points.

The bigger lesson is that you don't need to become obsessed with finding the magical number of repetitions that will suddenly unlock your fitness potential.

How many reps am I supposed to do, anyway? There isn't one.

Your goal matters. The exercise matters. The load matters. Your effort matters. Your technique matters. And your ability to recover from the work matters.

The research has given us more flexibility, not less structure.

So stop asking, “What's the perfect rep range?”

A better question is:

“What's the best rep range for what I'm trying to accomplish with this particular exercise?”

That's a much better question to take into the gym.

And thankfully, it doesn't require counting to 30 on every set.

Stop guessing. Start training with a purpose.

Your rep range should support your goal, not dictate it. Whether you're trying to build muscle, get stronger, improve performance, or train around an achy joint, your program should be built around you, not a one-size-fits-all rep chart.

Want help figuring out what your training should actually look like?

Book your Fitness Strategy Call and let's build a plan around your goals, your body, and the life you're living.

References

1. Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW. Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. Journal of Strength and Conditioning Research. 2017.

   
   

2. Carvalho L, Moriggi Junior R, Barreira J, et al. Muscle hypertrophy and strength gains after resistance training with different volume-matched loads: a systematic review and meta-analysis. Applied Physiology, Nutrition, and Metabolism. 2022.

   
   

3. Lopez P, Radaelli R, Taaffe DR, et al. Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis. Medicine & Science in Sports & Exercise. 2021.

   
   

4. Refalo MC, Hamilton DL, Paval DR, et al. Influence of resistance training load on measures of skeletal muscle hypertrophy and improvements in maximal strength and neuromuscular task performance: A systematic review and meta-analysis. Journal of Sports Sciences. 2021.

   
   

5. Grgic J, Schoenfeld BJ, et al. Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: A systematic review and meta-analysis.