The Overload Principle and Muscle Growth

What is the overload principle? And how can you apply it to your workouts to make your muscles bigger? Here’s everything you need to know.

What Is the Overload Principle?

The principle of progressive overload refers to the idea that you need to constantly increase the demands you impose on your muscles in order to stimulate adaptations in muscle strength, size or endurance.

Like most biological systems faced with a challenge, skeletal muscle will modify itself to meet similar challenges in the future.

Once the system has adapted to that demand, increases in muscle strength, size or endurance are no longer needed and will eventually stop… a situation you’ll need to avoid if you want to keep growing.

Do the same exercises, for the same number of sets and reps, while lifting the same amount of weight, for the next five years. Nothing much is going to happen.

Why not?

The training you’re doing is below the threshold required to stimulate growth. It’s a challenge your body has already adapted to. As a result, no new muscle will be gained.

Within certain limits, your muscle fibers will grow in direct proportion to the amount of work they’re required to do. And while there are many methods you can use to increase muscular work over time, these are the three to focus on.

The Progressive Overload Principle: An Example

According to popular legend, Milo of Croton began carrying a young calf on his shoulders each day.

The story goes that he would pick the calf up on a daily basis and walk around a large stadium. As the animal grew, Milo also grew stronger. Eventually, he was able to carry a fully-grown bull.

Personally, the whole thing sounds a little far-fetched. A fully-grown bull will typically weigh well over 1000 pounds. That’s a lot more than even the strongest guys in the world today can pick up and throw across their shoulders.

But the story does illustrate what is probably the most obvious way of putting the principle of progressive overload into action – adding weight to the bar while attempting to do the same number of repetitions.

In the context of weightlifting, the amount of weight you lift is known as training intensity.

A training intensity of 85% of 1-RM, for example, means that you’d be lifting 85% of your one-rep max, or the amount of weight you can lift for a single rep.

Let’s assume you’re currently following a training program that calls for three sets of ten reps on the bench press. Here’s what you did in the gym today:

• Set 1: 100 pounds x 10 reps
• Set 2: 100 pounds x 10 reps
• Set 3: 100 pounds x 10 reps

You did three sets, and managed ten reps in each set. Since you’ve reached the prescribed number of sets and reps, it’s time to increase the amount of weight you’re lifting.

The next time you do the bench press, add a bit more weight. Ideally, you’ll increase the resistance in small increments. A good rule of thumb is to add 5% or 5 pounds, whichever is the smallest.

In your next workout, you’ll be aiming for this:

• Set 1: 105 pounds x 10 reps
• Set 2: 105 pounds x 10 reps
• Set 3: 105 pounds x 10 reps

In other words, you’ll attempt to do the same number of repetitions and sets, but with an extra five pounds on the bar. I say “attempting” to do the same number of reps, because this won’t always happen.

The reality might look something like this:

• Set 1: 105 pounds x 10 reps
• Set 2: 105 pounds x 9 reps
• Set 3: 105 pounds x 8 reps

That’s why you’ll often see rep prescriptions given as a range, such as 8-12 reps, 5-8 reps or 12-15 reps, rather than a fixed number. If you’re pushing yourself hard in set one, it’s unlikely you’ll be able to do the same number of reps in sets two and three.

Here’s something else that’s very important:

The act of adding weight isn’t going to stimulate much in the way of muscular adaptations if your starting weight is too light.

For example, let’s say that your maximum in the bench press is 100 pounds for 3 sets of 10 repetitions. But when you train, you start off with just 50 pounds, and add 5 pounds to the bar in every workout.

Does this count as progressive overload training?

Not really. The weight you’re using is a challenge your body has already adapted to, and it’ll take several weeks of adding weight to the bar before those sets become challenging enough to stimulate growth.

What to Do When You Hit a Plateau

Adding weight to the bar (i.e. increasing intensity) works well in the early stages of training. However, it’s not going to keep working forever.

Most people won’t be able to add weight on a consistent basis from one workout to the next and retain the ability to do the same number of reps.

Let’s say, for example, that you go to the gym today and squat 100 pounds for five reps.

The following week, you add just 2.5 pounds to the bar. Do the same thing every week for 52 weeks, and you’ll be squatting with 230 pounds just one year from now.

Continue the process for the next five years and the weight you’re using will have risen to 750 pounds.

Sounds so simple doesn’t it?

Adding just 2.5 pounds to the bar each week is easy!

If you’ve been lifting weights for any length of time, you’ve probably realized already that this kind of continuous progress just doesn’t happen – no matter how hard you train, how many supplements you use, or how many motivational quotes you’ve been looking at on Pinterest.

Beginners are often able to add weight to the bar in every workout. But over time, the rate at which you gain strength will slow down.

This means that every incremental increase in load will need to be smaller, and take place less often.

What exactly do I mean by that?

A beginner in his first few months of training might start out getting strong five pounds at a time (i.e. he adds 5 pounds in weight to a particular exercise from workout to workout).

But those gains won’t keep coming at the same rate forever. Keep trying to add five pounds in every workout, and eventually you’ll start to miss reps. The increase in weight will outstrip your ability to adapt to that increase in weight.

So what can you do about it?

Option one is to get hold of some fractional plates. These are tiny plates that allow you to increase the weight you’re using by a very small amount – two pounds, one pound, or even fractions of a pound. 

From Practical Programming for Strength Training:

As progress begins to slow, i.e. as work sets become harder to do and to complete, or as reps begin to get missed, smaller incremental increases should be used. Smaller jumps waste time at first, but become absolutely essential later. Small plates are necessary for small jumps, and small jumps are necessary for progress.”

This is known as microloading, and is just enough to tease your body into lifting a little more weight than it did last time. Even small jumps in weight can generate some impressive gains over a long period of time.

Fractional plates come in particularly handy with exercises like the bench press and overhead press, where gains in strength tend to come more slowly than they do in the squat or deadlift.

Why is that?

Improving a 200-pound deadlift by 2.5% means getting 5 pounds stronger. Improving a 100-pound bench press by that same 2.5% means getting 2.5 pounds stronger.

But if the plates in your gym only let you add weight in five-pound increments, you’ll struggle to hit your rep targets.

What to Do When You Can’t Add Weight

It’s not necessary to add weight to every single exercise all of the time in order to stimulate muscular hypertrophy.

In some exercises, particularly the single-joint “isolation” movements, you simply won’t be able to add weight beyond a certain point. Nobody is doing lateral raises or concentration curls with 200-pound dumbbells.

Sometimes, adding weight isn’t a realistic goal. Going from bench pressing 100 to 105 pounds, for example, is a 5% increase in weight. But if you’re trying to go from curling a 15 to a 20-pound dumbbell, that’s a 30% jump in weight.

You can’t expect to increase the amount of weight by what is a relatively large amount and still get the same number of reps you did in the last workout.

Instead, try to crank out another rep or two with the same amount of weight. That is, if you did 10 reps in the previous training session, try to do 11 the next time.

This is one of the reasons I recommend keeping track of your workouts using a smartphone app or even just a notebook and pen. It lets you see what you did in your last workout, and try to beat it the next time around.

Adding reps is also one of the best ways to progress with bodyweight exercises like pushups or chin-ups.

The Double Progression Method

One way to combine the process of adding weight and reps in a systematic way is something known as the double progression method.

1. Add reps
2. Add weight
3. Rinse and repeat

You start out doing 3 sets of 8 reps. Over time, you keep on adding reps until you’re able to do 3 sets of 12. Then, you add weight, drop back to 3 sets of 8, and start the whole process all over again.

Doing 12 reps in all three sets serves as the trigger for adding weight. When you hit 12 reps, the weight goes up.

Here’s an example of how it might look in practice:

Workout 1

• Set 1: 20 pounds x 11 reps
• Set 2: 20 pounds x 10 reps
• Set 3: 20 pounds x 9 reps

Workout 2

• Set 1: 20 pounds x 12 reps
• Set 2: 20 pounds x 11 reps
• Set 3: 20 pounds x 10 reps

Workout 3

• Set 1: 20 pounds x 12 reps
• Set 2: 20 pounds x 12 reps
• Set 3: 20 pounds x 11 reps

Workout 4

• Set 1: 20 pounds x 12 reps
• Set 2: 20 pounds x 12 reps
• Set 3: 20 pounds x 12 reps

The exact number of workouts it takes to reach this point will vary from person to person, and from exercise to exercise. It might take 10 workouts or it might take 5. But don’t add weight until you’re able to do 3 sets of 12 reps.

If you only just managed to crank out that final rep by shortening your range of motion or cheating excessively, then don’t add weight. You want to be able to complete the prescribed number of reps in all three sets using good form.

Carry on like this for as long as you can, constantly pushing your muscles and giving them a reason to adapt and grow. Add weight… add reps… rinse and repeat.

Your progress won’t always be this consistent, and you’re not going to improve every time you go to the gym. To do so indefinitely would be impossible.

There’ll be times when you end up lifting the same amount of weight, for the same number of sets and reps you did in the previous workout.

However, the focus of a hypertrophy training plan should always be on pushing yourself to increase the amount of work your muscles are doing, whether that’s lifting heavier weights, or doing more reps with the same weight.

You need to give your muscles a reason to grow or they’ll remain stuck at the same size they are right now.

Doing just one extra rep sounds like it should be easy. And in the early stages of training it will be. But just like adding weight, you won’t be able to keep it going forever.

That’s when it’s time to apply the overload principle in a different way, and increase your training volume.

The Overload Principle and Training Volume

There are various different ways of defining training volume, from volume load (sets x reps x weight) to the total number reps you do for a particular muscle group.

Adding weight and repetitions will increase training volume to some degree. That is, when you do more weight for the same number of reps, or the same number of reps with a heavier weight, your volume load will increase.

For example, if you bench press 100 pounds for one set of 10 repetitions, your total volume load (sets x reps x weight) is 1000 pounds (1 x 100 x 10 = 1000).

When you add an extra five pounds to the bar, and do the same 10 reps, your volume load has increased to 1050 pounds (1 x 105 x 10 = 1050).

It’s the same story when you add an extra rep.

Do 11 rather than 10 reps with that same 105 pounds, and your total volume load has risen from 1050 to 1155 pounds. In other words, when you add weight and reps, your volume load will increase as a natural byproduct of doing both of those two things. 

However, I’m defining training volume here as the number of hard sets you do for a given muscle group.

And by a hard set, I’m talking about a set that takes you within a rep or two of muscular failure – that point where you’re unable to finish a rep without cheating or getting help from a spotter.

There are two main ways to increase your training volume – by doing more sets on a per workout or a per week basis.

Let’s say, for example, that you’re currently training your chest once a week, and doing a total of six sets in that workout. 

• Bench Press 3 sets x 5-8 reps
• Incline Dumbbell Press 3 sets x 10-15 reps

If you add a single set to each exercise, your training volume has now increased by 30%. Before, you were doing six sets. Now you’re doing eight sets.

Your muscles are doing more work than they were before, and should adapt to the extra work by getting bigger.

However, one of the problems with increasing the number of sets you do is that the duration of your workouts is going to increase. This isn’t always practical if you have a limited amount of time to spend in the gym.

And time isn’t the only limiting factor. Eventually, you’re going to run out of energy, motivation or both.

What’s more, there’s a ceiling on the training stimulus your muscles can respond to in any given workout. 

As an example, let’s say that doing 6 sets rather than 3 sets per muscle group speeds up growth by 25%. Going from 6 to 9 sets might increase growth by 10%. A further increase from 9 to 12 sets might have no additional benefit.

In other words, increasing the number of sets you do in a single training session can be an effective way to apply the overload principle, but only up to a point.

Which brings me to the second way of adjusting volume – increasing training frequency, or the number of times each week a muscle group is trained.

Again, let’s assume you’re training your chest once a week, and doing a total of six sets for the chest in that single workout. 

Instead of adding more sets, you’re going to add a second workout, so your chest is trained twice rather than once a week. You’ve doubled your training volume by increasing your training frequency, going from 6 to 12 sets. 

Again, you’ve successfully applied the overload principle in the sense that the muscles in your chest, shoulders and triceps are doing more work than they were before.

It’s not, however, a good idea to keep adding sets forever. If there were a perfect linear relationship between training volume and muscle growth, then building muscle would simply be a case of increasing the number of sets you do.

But you can’t just keep adding sets ad infinitum and expect to grow. Sixteen sets per muscle group per week might be better than eight, but it doesn’t necessarily follow that 32 sets will work better than 16.

In other words, there’s an optimal training volume, above and below which gains in size will be slower than they otherwise would be.

Training Density

Something else I want to touch on is training density, which involves attempting to lift the same amount of weight for the same number of reps while decreasing the amount of rest time you take between sets.

For example, you might start out resting for two minutes between sets of the same exercise. 

In the next workout, you knock 10 seconds off and start the next set sooner. Then you do the same thing again in the next workout, repeating the process until your rest period between sets is down to one minute.

Decreasing rest time is one of my least favorite ways to apply the overload principle, at least from the point of view of building muscle mass. Why?

The big problem with reducing the duration of your rest intervals is that it reduces the number of reps you’re able to lift in subsequent sets.

In fact, most studies comparing short (60 seconds or less) with longer (2-3 minutes) rest periods show faster gains in both muscle mass and strength with the latter [1, 2].

Why do longer rest intervals work better?

As the rest intervals go down, the accumulation of fatigue goes up. This limits the amount of weight you can lift, and the number of reps you’re able to do.

As a result, the strength of the muscle-building stimulus generated by a given workout is weakened, and muscle will be gained more slowly.

It’s much the same story with rep tempo, which refers to the speed at which each rep is performed.

A reduction in rep tempo will often make an easier feel harder, but that doesn’t necessarily mean that it constitutes an effective form of overload training.

Most research comparing fast and slow rep speeds fails to show that slowing down each repetition will make your muscles grow any faster.

The Importance of Taking a Break

Your body isn’t a machine, and you will benefit from taking a rest every now and again.

Whether you decide to take a break after 6 weeks, 8 weeks, 12 weeks or whenever, as well as the type of break you take (whether it’s a complete break from training or just a light week), is a personal choice. 

Everyone is different. If you’re feeling motivated and seeing results, there’s no reason to stop. 

But if you’re feeling a bit frazzled, and seeing some of the early signs of overreaching, such as changes in mood, more frequent illness, minor muscle or joint niggles, a poor appetite or just a general lack of motivation, it’s time to give yourself some time off.

Taking a break can be hard to do, especially if you’re the type who sees any amount of time off as a wasted opportunity for progress. You worry that you’ll lose some of your gains, and almost feel guilty about the fact you’re not in the gym.

I understand the fear that taking your foot off the gas will make you weaker, but most people will see better results in the long run by doing so. After taking a complete physical and mental break from training, you’ll often come back feeling refreshed and motivated. 

I know it’s a cliche, but sometimes you need to take a step back in order to take two steps forward.

Why Progressive Overload Gets Harder Over Time

The major limitation with all methods of progressive overload is that the performance curve will eventually flatten out, and you’ll hit a plateau.

Beginners will often improve from workout to workout for months on end.

But once you’ve moved past the beginner stages of training, progress will come not from workout to workout, but from week to week, then from month to month, and eventually a lot more slowly than that.

At first, progress is relatively easy. But as you move closer to your goal, taking the next step becomes more and more difficult.

“As is true with most systems that improve with accumulated change, the farther away from the predetermined limits of potential improvement the system is, the more easily and rapidly the system improves,” explains Mark Rippetoe in Strong Enough.

“The closer you get to the limit, the harder it is to get closer, the longer it takes, and the more it costs in terms of effort and (usually) expense.”

What’s more, the gains won’t come in a predictable, steady fashion from one week to the next. 

Progress tends to come in waves. In some workouts you’ll surprise yourself with how much of a jump you make, in some you may end up repeating what you did in a previous session, while in others you might end up going backwards. 

If you zoom out and look at your results over a period of months and years, you’ll be able to see the gains being made. But on a week to week basis, it can sometimes feel like you’re not getting anywhere.

Final Thoughts

Putting the overload principle into practice involves training with a purpose. Having goals to reach, as well as a plan to reach those goals. Do the exact same workout for months on end, and your body will never change.

When you’re just starting out, you’ll often see results no matter what type of training you do, just as long as you’re consistent. After a couple of years of solid training, however, you have to pay a lot more attention to the finer details if you want to keep the gains coming and avoid a plateau.

But even then, it’s still very difficult to keep on adding weight and reps.

So be prepared for the fact that your progress in the gym will slow down over time. It’s quite normal and doesn’t mean you’re doing anything wrong.

Even the best training program won’t change the fact that every step on the path to physical greatness will be a little slower and harder than the last.