Building muscle is less about special exercises or the “perfect” rep range, and more about taking a balanced approach to your training program. There are 3 primary methods of building muscle, and those 3 methods are best utilized if you combine low reps (1-5 reps), moderate reps (6-10 reps), and high reps (12+ reps). Adjusting these variables over time is the best way to gain muscle and maximize your genetic potential.

If you were to strip down the process strength training for building muscle into what matters most, you’d find two primary areas of focus: training (how you exercise) and recovery (how you eat and fuel your body, this is where nutrients like protein are so important).

From a weight training perspective, there are three primary mechanisms of muscle growth for every muscle group: muscle tension, metabolic stress, and muscle damage.

To most people, these three concepts mean very little. To scientists, they are the holy grail of transforming your body -- and the reason why so many workout programs lead to more frustrations than results.

Here’s a quick overview that will help you understand the amount of weight to use when strength training, so you know when to use higher reps or when to use fewer reps to add muscle mass.

Method 1: Metabolic Stress

Metabolic stress is the “feeling” you get when your muscles become exhausted. Call it the pump or a burn, this process doesn’t just remind you that you’re training hard, it also plays a role in hypertrophy.

Metabolic stress triggers a process that ultimately results in your muscle cells being “turned on” to help you build muscle mass. That means your muscles are more likely to pull water into your muscle cells, which can help them grow.

The beauty of metabolic stress is that it can be created with less focus on the amount of weight you use, meaning light weights and higher reps have a place in your workout program. 

Method 2: Muscular Damage

Muscular damage can occur in many ways.  In the simplest sense, any type of weight training -- whether you’re using dumbbells, barbells, or just your bodyweight -- will cause damage (the good kind) that forces your muscles to repair grow back bigger and denser, which will result in more muscle mass.

Eventually, your body will adapt to that stress, and you need to find ways to adjust your workout program to challenge your muscles if you want them to keep growing. You can increase muscular damage by:

  1. Lifting heavier weights.
  2. Trying a different technique (such as training a muscle from a different angle).
  3. Focusing on the lower (eccentric) portion of the lift. [Research shows that more muscle damage occurs during this phase.]
  4. Adding more volume (you can accomplish this by doing more reps and/or sets).
  5. Changing tempo, such as taking more time to raise or lower weight, in order to create more tension.

When you add in one new variable (like using a heavier weight with the same number of reps) -- or multiple (using a heavier weight for more reps) -- as a way to increase muscular damage, you can keep making progress.

More importantly, it’s important for you to know that building muscle can be done in many ways. You can use heavier weights and lower reps, but muscle growth is not dependent on just using more weight. You can add more volume (increase sets and do higher reps) by using lighter weights, and that can still play a role in adding new muscle.

Method 3: Tension

Muscle tension can help promote all three mechanisms of muscle growth, and it’s probably the aspect of strength training that's most difficult to understand and master.

Tension is about letting your muscles do the work, and not allowing your form to break down and lift a weight by any means possible. That’s how you end up injured, and it’s also why so many people gain “deceiving” strength. You learn to move a weight, but because the tension of the weight is not in your muscles, you don’t see the type of growth you’d expect.

When you try to move a weight using any means possible, your form might break down, ligaments and joints can take on a greater load, and while you might get the job done, your muscles aren’t necessarily carrying as much of the load as you want for growth.

This variable then is less about your workout program and more about how you execute each movement. So, how should you lift differently?

Instead of thinking of pushing or pulling a weight, try to focus on a full range of motion that creates constant tension on the working muscle. Whether you're performing fewer reps with a heavier weight or more reps with a lighter weight, you want to make sure your muscles do not take a break. It’s a constant process of stretching the muscle (the eccentric) and squeezing the muscle (the concentric).

While it’s not a hard rule, constant tension usually means stopping your lifts just short of lockout on the lifting portion (think of flexing your bicep), and then a little short of the “bottom” of the lift to maximize the stretch (when lowering the dumbbell or barbell to the point that you feel a stretch in your bicep, but not to where you lock out your elbow.).

In other words, it tends to be about 90 percent of the range of motion on both ends, which ensures non-stop tension and an environment for building muscle.

When you understand “tension,” it makes it easier to apply the other mechanisms of muscle growth to any strength training program. 

Muscle Growth 101

You’ve likely been lead to believe that one rep range is “best” for building muscle. That range (8-12 reps) is certainly important, but committing to that one approach is a big reason why so many workout programs start fast...and then fizzle out even faster.  

Training programs need to find different ways to adjust workout volume. When you understand that there are 3 factors (and none are dependent on any one particular exercise or a set of exercises), it will make it instantly easier to assess if your program is a good fit.

For instance, if your strength training program only uses one rep range the entire time (such as 8-10 reps), it’s most likely not ideal for muscle building for the long-term.

Or, if a program insists that you can only build muscle if you perform very specific exercises, then it’s also probably misleading. While certain exercises are proven to target different muscle groups the best, there are so many variations of exercises that can help you build muscle that there’s no reason to be married to a movement that might not be a good fit for your body.

All three aspects of muscle growth are connected. Muscle tension with heavier weights can cause muscle fiber damage that allows for swelling and metabolic stress to occur. And then that promotes growth.

Muscle tension with lighter weights, more reps, and more time under tension triggers metabolic stress, during which blood can’t escape your muscles quickly enough and your muscles are forced to grow. And then tension with moderate weight for more reps or different exercises ignites both metabolic reactions and damage.

If you want to add muscle mass, you need to look at the big picture when you design any muscle-building workout and use several tactics, not just hope that showing up in the gym will translate to bigger biceps.

Now that you have a very general idea of what to look for, we’ll help you see exactly what it takes to build muscle -- at any age -- and design the right program for you.

Your Muscle Building Program

Before you begin designing a workout program, always remember that every person's body is different. So while these strategies will work for anyone, you might find that you grow better with one technique than another.

That’s not a reason to ignore any of the three approaches, but it does mean that you might emphasize one tactic more than another. Some people might see incredible progress with only lifting heavy weights, whereas others might see it with moderate weight for more reps.

If you want to really focus on building muscle — and not just becoming stronger or being able to train harder — then variety is your best friend.

The key is increasing training volume in different ways. It can be done by. blending a mix of low (1-5), medium (6-12) and high (15+) rep ranges to ensure that you’re triggering all of the processes of muscle growth.

Because some exercises are best for gaining strength, while others are ideal for tension, or creating the pump, you’ll want to include diversity in your training plans.

This doesn’t mean altering up your workouts every day, but it does mean going through cycles where you rotate your reps and the movements you perform.

Exercises for strength will include the “big lifts” like squats, deadlifts, presses, and rows. Variations of these lifts from different angles (such as an incline press) or in ways that create different stressors (like doing sumo deadlifts or Bulgarians split squats) will challenge your muscles in new ways that force growth.

Even “isolation” exercises, such as curls, shoulder raises, leg curls, and cable exercises, will help create more tension at lighter weights that will allow for the pump and growth. Rest periods should be cycled, too, with longer recovery periods to help you lift greater loads, and shorter rest periods to fire up the metabolic damage.

The final layer? Slowly do more. Volume (sets x rep x weight) is an important part of gaining muscle. But, most people just try to do more, more, more.

If this were a diet and you just ate a lot more immediately, you wouldn’t gain muscle, you’d become fat. While more volume won’t make you fat, it can slow or stunt your progress.

Instead, the goal is to add a little volume week over week. The result: Constant progress, changes you can see, and avoiding the dreaded plateau.

To get you started, here’s a sample workout from BJ Ward, CSCS, Head Coach at Born Fitness. Follow to a T, or use as a template and adapt as you want.

The Muscle Mass Workout Program

How to Do It

Perform this strength training workout at least 3 times per week. When there is an exercise pairing (ie 1A and 1B), perform as a superset, which means you do the exercises back-to-back with minimal rest, and then break after you complete the pairing.  

Day 1 (Push)

The Warmup

1) Plank to Down Dog 2 sets x 6 reps

2) Resistance Band Face Pull 2 sets x 15 reps

The Workout

1. Tempo Push-up 2 sets x 8 reps (rest 60 seconds between sets)

2. Single-Arm Dumbbell Bench Press 3 sets x 5 reps/arm 

(rest 60 seconds between sets)

 3. Kettlebell Single-Arm Arnold Press 3 x 6-8 

 4. Incline Dumbbell Press 4x 6-8

 5A. Split Stance Landmine Press w/ :3 lower 4x8ea

 5B. EZ Bar Tricep Extension 3x10-12


Day 2 (Pull)


1. Glute Bridge 2x10

2. Lateral Band Walk 2x5yds ea


1. Straight Arm Pulldown 2 sets x 8 reps

2. Trap Bar Deadlift 3 x 5

3. Chest Supported Rows 4 x 10

4. Narrow Grip Chin-up 3 x 6 (add weight if needed)

5. Seated Face Pulls 4x10

6A. Dumbbell curls 3 x 10

6B. Farmers Carries 3 x 30 yards


Day 3 (Lower Body)


1. Lateral Lunge 2 x 8 per leg

2. Side plank w/ Clamshell 2 x 10 per side


1. Physioball Leg Curl 2x8

2. Barbell Front Squat 3x5

3. RDL 4x8

4. Front Foot Elevated Reverse Lunge 3x6-8ea

5. Tempo Goblet Squat 4x8