How Many Reps for Mass: The Magic Number Uncovered

When it comes to building muscle mass, there are so many different strategies and methods out there that it can be hard to know where to begin. One area of confusion for many people is how many reps they should be doing in each set. Some swear by low reps and heavy weights, while others swear by high reps and lighter weights. So what’s the magic number for mass? Let’s dive in and uncover the truth.

The Science of Reps

Before we can talk about how many reps you should be doing, we need to understand a little bit about how reps work. When you lift weights, you’re creating small tears in your muscle fibers. Your body then repairs those tears, making your muscles bigger and stronger in the process. The number of reps you do can affect which muscle fibers you’re targeting and how much damage you’re doing to those fibers.

Low reps and heavy weights are great for building strength, but not necessarily for building mass. That’s because when you lift heavy weights for just a few reps, you’re primarily targeting your type II muscle fibers. These are the muscle fibers responsible for explosive movements, like sprinting or jumping. They’re also the muscle fibers that have the most potential for growth.

On the other hand, high reps and lighter weights target your type I muscle fibers. These are the muscle fibers responsible for endurance activities, like distance running or cycling. They don’t have as much potential for growth as type II fibers, but they can still contribute to overall muscle mass.

So, What’s the Magic Number?

The short answer is that there is no one magic number when it comes to reps for mass. The optimal number of reps for you will depend on a variety of factors, including your goals, your fitness level, and your genetics.

That being said, there are some general guidelines that can help point you in the right direction. For most people, a rep range of 8-12 reps per set is a good starting point for building mass. This rep range targets both type I and type II muscle fibers, creating a good balance of endurance and strength training. It also provides enough time under tension to create the necessary muscle damage for growth.

Keep in mind, however, that this is just a starting point. You may find that you respond better to higher reps or lower reps, depending on your individual needs. It’s also important to vary your rep ranges over time to prevent plateauing.

The Importance of Tempo

When it comes to building mass, reps are only part of the equation. Tempo, or the speed at which you perform each rep, is also crucial. By controlling your tempo, you can help create more muscle damage and facilitate more growth.

The eccentric, or lowering, portion of the lift is particularly important for creating muscle damage. By slowing down the eccentric portion of the lift, you force your muscles to work harder, creating more damage in the process. This can lead to greater gains in muscle mass over time.

Sample Rep Tempos

If you’re not sure how to control your tempo, here are a few sample tempos to get you started:

  • 2-1-2: Two seconds to lift the weight, one second pause at the top, two seconds to lower the weight
  • 3-0-1: Three seconds to lower the weight, no pause at the bottom, one second to lift the weight
  • 1-0-3: One second to lift the weight, no pause at the top, three seconds to lower the weight

Experiment with different tempos and see how your body responds. Just remember to keep your form safe and controlled at all times.

The Importance of Progression

No matter what rep range or tempo you use, one of the most important factors in building mass is progression. Essentially, this means gradually increasing the weight you’re lifting over time.

Why is progression so important? As you get stronger, your body adapts and becomes more efficient at using the same weight. In order to continue creating muscle damage and growth, you need to continually challenge yourself with heavier weights.

Progression doesn’t have to be drastic. Simply adding a few pounds to your lifts each week can make a big difference over time. You can also use techniques like drop sets, supersets, and pyramids to help increase the intensity of your workouts without necessarily adding more weight.

The Bottom Line

So, how many reps should you be doing for mass? In general, a rep range of 8-12 reps per set is a good starting point. However, the optimal rep range for you will depend on a variety of factors, including your goals, your fitness level, and your genetics. Regardless of the rep range you choose, be sure to control your tempo and focus on progression over time.


Here are answers to some of the most common questions about reps and mass:

  • Q: Do high reps burn fat and low reps build mass?
    • A: No, this is a myth. The number of reps you do doesn’t affect the amount of fat you burn. It’s true that heavy weights and low reps can help build more muscle mass, but you can still build muscle with higher reps and lighter weights.
  • Q: Is it better to lift heavy or light weights for mass?
    • A: Both heavy and light weights can be effective for building muscle mass. Heavy weights and low reps target your type II muscle fibers, which have the most potential for growth. Light weights and high reps target your type I muscle fibers, which can also contribute to overall muscle mass. Ultimately, the best approach is to incorporate a variety of rep ranges into your workouts and focus on progression over time.
  • Q: How often should I switch up my rep range?
    • A: It’s a good idea to vary your rep range every 4-6 weeks to prevent plateauing. You can switch between lower reps and heavier weights and higher reps and lighter weights, or try out different rep tempos.
  • Q: How much weight should I add when trying to progress?
    • A: The amount of weight you add will depend on your individual strength level. As a general rule, try to add 2-5 pounds per week to each of your lifts (depending on the lift). This gradual increase over time can lead to significant gains in strength and muscle mass.


1. Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2016). Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis. Journal of Sports Sciences, 35(11), 1073-1082.

2. Campos, G. E., Luecke, T. J., Wendeln, H. K., Toma, K., Hagerman, F. C., Murray, T. F., & Staron, R. S. (2002). Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. European Journal of Applied Physiology, 88(1-2), 50-60.

Leave a Reply

Your email address will not be published. Required fields are marked *