What is the best rep range for muscle size?

By Coach Hunter Bennett

When it comes to building muscle, a common question is “what’s the best rep range for muscle size?”

You may have heard 8-12 reps is the perfect “hypertrophy” range, or that you need to lift heavy with low reps to pack on serious size. You might have even heard that you need to do sets of 25 reps or more to “seriously shred the muscle.”

But what’s the truth?

Rep Ranges for Muscle Size: The Surprising Truth

Recent research has shown that muscle growth can occur across a wide range of rep schemes—as long as you’re training to failure, or close to it.

In fact, muscle growth seems to be about the same if you are going as low as 5 reps, or as high as 30, if they are both pushed hard.

Now obviously the range of 5-30 reps is a pretty broad one, and there are other things you should consider when working out the best rep range for muscle size.

Why Not Always Do 30 Reps?

If muscle growth is similar across all rep ranges, you might wonder why you wouldn’t always go for the high end and do 25 or 30 reps every single set.

After all, it’s less taxing on your joints, and might even require less time to warmup.

However, there are some downsides:

1. Time Efficiency: Doing 30 reps simply takes longer than doing 10, and when you factor in multiple sets and exercises, that extra time adds up. For most people, a workout that’s both effective and efficient is the goal.
2. Progressive Overload: Lifting heavier weights is likely to have more of an impact on strength, which makes it easier to add load on a weekly basis. This is key to long-term progress, as your muscles need to be challenged to adapt.
3. High Discomfort: High-rep sets can be mentally and physically exhausting and lead to form breakdown. This can lead to really high levels of fatigue, especially in compound movements like squats or deadlifts.

Why Not Always Go Heavy?

On the other hand, you might be wondering why not always do sets of 5 or 6 – I mean, this is likely to maximise strength gains while also causing muscle growth.

While this is true, always lifting heavy also has some downsides.

1. Longer Rest Periods: Lifting heavy often results in longer rest periods. This can seriously increase the time of your sessions, making them less practical.
2. More Joint Stress: Lifting heavy is more taxing on your joints, and doing too much volume of heavy lifts may increase the chance of overuse injuries occurring.
3. Less Long-Term Growth: Lifting heavy general results in less metabolic stress, which is thought to contribute to muscle growth. While this is speculative, there is some evidence to suggest that doing some high rep work might help grow slow twitch muscle fibres, which are not stimulated as much when doing lower reps. As such, only doing low reps might limit your muscle growth in the long-term.

The Best Rep Range for Muscle Size: 6-15 Reps

While you can build muscle with as few as 5 reps or as many as 30, most people find that sticking to the 6-15 rep range most of the time offers the best balance of time efficiency, progressive overload, and focus.

This range allows you to lift relatively heavy weights, which helps increase strength, while also going high enough to get some of that metabolic stress I discussed earlier.

That isn’t to say you should never deviate from this rep range.

Lower rep ranges (3-5) are the best for building strength, which can indirectly boost muscle growth by allowing you to lift heavier weights in your hypertrophy-focused sets.

On the other hand, higher reps (15-30) can improve muscular endurance and give your joints a break from heavy lifting.

So don’t be afraid to mix it up every now and then.

How to Program for Muscle Size?

Now you might be wondering how to program for muscle size when considering this rep range, and it comes down to exercise selection.

We recommend training your primary compound exercises at the start of the session for sets of 5-6, with 1-2 reps in the tank each set. This is a great way to build strength and size of the prime movers.

For your secondary exercises – which should also be compound in nature – we recommend aiming for 8-12 reps, pushed close to failure (i.e., 1 rep in the tank).

Finally, for all your isolation exercises that come at the end of the session, we recommend performing for 10-15 reps, with every set going to failure.

Here is an example of what this might look like on a lower body day:

The Best Rep Range for Muscle Size: Take Home Message

If your goal is to build muscle, you’ve got plenty of options when it comes to rep ranges. The key is to push your sets close to failure and ensure you’re progressively overloading your muscles over time.

While the 6-15 rep range is likely the most practical and effective for most people, don’t hesitate to explore different rep ranges for a bit of fun.

If you are not sure where to start, check out some of our programs or feel free to contact us for more information.