The Solution to Long-Term Muscle Mass Gains: An Overview of the P.B.S. Model

Tom MacCormick
Written By: Tom MacCormick
April 27th, 2021
Updated: September 30th, 2021
7.5K Reads
P.B.S. The Solution to Long-Term Gains in Muscle Mass
Intelligently plan your training for maximum mass with this 3-phase program. The P.B.S. model will help you build your strongest and most muscular body yet!

Most guys can design an effective workout, but they are clueless when it comes to designing an effective program. This is a big problem and one of the major causes of stalled progress. What works now won’t work forever. The body is an incredible adaptive mechanism. This is great for your survival and problematic for your gains. A by-product of this fact is the phenomenon of adaptive resistance. The more the body is exposed to the same stressor, the less disruptive the stressor is. That’s why the workout you did a few weeks ago which completely crushed you feels like a breeze a few weeks later.

To navigate the body’s in-built protective mechanisms, you need to intelligently plan your training with one eye on what will work now and another on what will work after the effectiveness of this training has worn off. This is complicated. It’s taken me years of studying and practical experience to master.

Recommended: Need help building muscle? Take our Free Muscle Building Course

Phase Potentiation

When I first began training I randomly followed workouts from magazines. There was no continuity and no long-term plan. Sometimes I’d happen across a program that yielded fantastic results and think that program was magical. In reality, I’d just been fortunate and stumbled across a routine that happened to use what I had been doing as a launchpad to faster gains. This I would later discover was known as phase potentiation.

What is Phase Potentiation?

Phase potentiation is when the phase of training you are doing now capitalizes on the work you did in the phase before and lays the foundations for enhanced results in the next phase. When used properly it creates the potential for more effective training and it extends the time period of effective training.

When you properly utilize phase potentiation, you get a synergistic effect. Stacking blocks of sessions together suddenly felt like a 1+1=3 scenario rather than the 1+1+1+1+1=2 effect I got from program hopping my way around random internet workout routines as a beginner.

How Does Phase Potenation Work?

To properly apply phase potentiation, you need to understand what systems are adapting to what stimulus and then change the stimulus enough to challenge different systems or overload the same system.

From an energy system perspective, this could be transitioning from aerobic capacity training, aerobic power, to anaerobic capacity. With strength qualities, this could be moving from a GPP block to a hypertrophy phase, to strength, and finally to power.

When it comes to hypertrophy, it is a little bit less obvious how to make changes to keep growth coming. I have experimented with phase potentiation for size gains for the last 6 years. The results have been excellent. Over the past year, I have made one major adjustment to the way I do things and my clients have had even better results. The principles I was applying before are all in place, but the exact format of these principles has changed in a subtle way that has magnified the effectiveness dramatically.

Related: 4 Day Power Muscle Burn Workout Split

The P.B.S. Model

This has helped me to formulate the P.B.S. model: a 3-phase system designed to address the issue of adaptive resistance and extend the effectiveness of muscle-building programs. After much trial and error, this P.B.S. system has been refined to a 20-week mass-gaining monster.

There are three distinct phases:

  1. Primer
  2. Building
  3. Solidification (strength)

The primer phase lays the foundations for effective muscle-building training. It creates a bigger window of opportunity. Another way to think of it is that it lengthens the runway available for bulking.

The building phase is where most of the muscle-building occurs. Hence the name. The building phase is actually divided into four sub-phases.

The solidification phase is crucial because it allows you to consolidate the gains you have made. Your body adjusts to the “new normal” higher body weight and increased muscle mass you carry. It “owns” this new mass, or in my terminology, it allows your gains to solidify. As a result, when you transition to a fat loss phase you hold onto all the muscle you’ve built. If you skip the solidification and go straight to cutting from bulking, and you risk losing a significant portion of the muscle you’ve built.

Here are some critical points that explain why strategically varying your program over time is essential to building the most muscle possible:

  • Your body adapts faster if it is only adapting to one stimulus.
  • The longer you do the same training the body becomes more resistant to change in response to that training. This is known as adaptive resistance.
  • If you want to build size AND strength, you will do better addressing them sequentially instead of trying to do both at once.
  • Maintaining physical quality is much easier than building it. So, by developing strength, you can easily maintain this while switching focus to hypertrophy and vice versa
  • Periods of time away from a specific training stimulus “re-sensitizes” you to it so that when you return to that training style in the future, you are more responsive to it.
  • Sequential training provides both a new physiological and psychological stimulus. This increases motivation, enthusiasm, compliance, and results!

What Makes a Successful Training Program?

Every successful training program has at least two things in common:

  1. Specificity
  2. Progressive overload

Specificity means that all of your training is specific to your goal. Your training is designed to tax the physiological pathways that will create the results you want. In the case of this article, those pathways are those that cause muscle gain.

Progressive overload has two components. Firstly, that for your training to be effective it has to provide a robust enough stimulus to represent an overload on the body. Secondly, over time this stimulus will have to increase as your body adapts. Long story short, your training has to be hard and it has to (on average) get harder over time.

So, the question is, how should you train in a manner that is specific to muscle gain and how can you provide a progressively overloading stimulus over the long term?

Maximizing Hypertrophy

Three key mechanisms of hypertrophy have been identified. These are:

  1. Mechanical tension
  2. Muscle damage
  3. Metabolic stress

As more research has been conducted on these mechanisms and their relationship with hypertrophy, it appears that mechanical tension is the most important. Metabolic stress appears to play an additive role but to a much lesser degree. Muscle damage, meanwhile, appears to be more of a secondary mechanism of hypertrophy. By that I mean, it is more a consequence of training strategies that achieve high degrees of mechanical tension and metabolic stress that then contributes somewhat to muscle gain.

On that basis, it seems logical to structure your training in a way that prioritizes mechanical tension. Incorporating some metabolic stress style training will enhance your results. Specifically targeting muscle damage, however, seems less important. Instead, just realize that by working sufficiently hard training the other two mechanisms you will by default cause some muscle damage.

Training Volume

Another key variable to consider when it comes to hypertrophy training is training volume. Training volume is a metric of your overall workload. It can be measured as volume load (sets X reps X load) or simply the number of hard sets you do.

The scientific literature indicates that training volume has a dose-dependant relationship with muscle gain. That is to say that, the more training volume you do (without exceeding your capacity to recover) the better your results.

At this point it should be clear that for effective long-term gains in muscle mass you need to do the following:

  1. Focus on training methods that create high degrees of mechanical tension
  2. Utilize metabolic stress techniques
  3. Increase training volume over time

So far, so simple. You just need to keep doing more training. Chasing more mechanical tension, catching insane pumps, performing ever more training volume is, in many ways logical. Rinse repeat and you’ll be carrying a pro-bodybuilder level rig in no time. Not so fast! Just doing more of the same doesn’t work as a long-term solution.

How to Avoid Adaptive Resistance

Strategically changing your volumes and intensities helps to avoid "adaptive resistance". This is your body's tendency to adapt less and less when presented with the same monotonous training stimulus.

The body is smart. It adapts to almost everything we throw at it. There is no need for it to keep adapting to the same stimulus though. Once it has adapted to the point it can handle the stress you put it through, it no longer needs to allocate resources to continue to adapt. Once your body is accustomed to your workouts it doesn’t need to spend valuable energy building your muscles. Essentially, it means there are diminishing returns when you keep repeating the same workouts over and over again.

So, you must plan to vary your training over the course of the year to strategically challenge different pathways. Allow time for the accumulated fatigue and adaptive resistance to subside and then push the hypertrophy mechanism-focused training again. This will allow you to make the best gains possible. From a physiological sense, this approach works extremely well. From a psychological perspective, it is also extremely powerful so it keeps your training fresh.

Strategic Variation for Muscle Mass

The most important thing for continuous muscle-building progress is not doing more of the same thing forever. It's strategically changing the type of stimulus you impose on your body. Whether you train with high levels of mechanical tension, training volume, or generate incredible amounts of metabolic stress, if you stay with the same program too long, you're still providing the same stimulus. In time, adaptive resistance will kick in and results stop coming. As Christian Thibaudeau puts it, your body becomes "immune" to the training stimulus.

All of the training variables have a shelf life. They all work. They just don’t work forever. The only thing you can constantly change is the nature of the stimulus. The good news is that as you pursue a different stimulus you “re-sensitize” yourself to the ones that had stopped working.

For muscle growth, the key to long-term progression is changing the stimulus imposed on your body. By taking a step back, assessing the various methods available and how they complement each other, you can put together a very effective multi-phase training plan.
Of course, these changes have to be planned in a smart and progressive way. And they still have to make the body work harder.

Related: Strategic Variation for Maximum Muscle Growth

How Often Should I Vary My Training?

The less experienced you are, the longer you can stay on the same program. As a beginner, you can follow the same plan for several months and still see great progress.

The longer you’ve been training, the more frequent the changes need to be. They don’t need to be radical changes, but as an advanced lifter, making some small adjustments to your programming every 3-4 weeks is a smart move.

What Do I Change?

Some variables should be changed more frequently than others. In my opinion, changing rep ranges relatively often works well, but switching exercises often is a bad idea. Changing exercises provides a mostly neurological stimulus. You are exposed to a new motor pattern and have to learn this skill. This can be quite useful for certain sports and if done intelligently can work for strength goals. It leaves a lot to be desired from a muscle-building perspective though.

To build muscle, you want to make the target muscle the limiting factor. A set should stop because that muscle has been fatigued, not because of technique breakdown, a lack of postural endurance, or fatigue in other muscle groups. To achieve this a high degree of skill in executing a given lift is required. That way you can maintain form and focus on challenging the target muscle. If you have faulty motor patterns or are just learning an exercise, the technique will be your limiting factor, not the muscle. This is not ideal for muscle gain. Changing the exercises too often can also limit your gains because you never become efficient in a movement. Consequently, I prefer to keep the core of the exercises within a program the same for a while (or at least use close variants), but change rep ranges more often.

The P.B.S. framework is designed for experienced lifters. Beginners don’t need this level of programming detail or strategic variation to progress. Eat big, lift big will serve you well as a beginner. However, as you close in on your genetic potential, you will need more attention to detail to keep making gains.

Related: 5 Frequently Asked Questions When Choosing Your Next Workout Program

The P.B.S. Phases – An Overview

Primer Phase

The primer phase focuses on quality over quantity. The relatively low training volume leaves you a greater runway to push volume up as a driver of hypertrophy in the building phase. The primer phase works on developing the 4 ‘S's”. These are:

  1. Skill
  2. Stability
  3. Structural balance
  4. Strength (in end ranges)

During the primer phase, a big emphasis is placed upon improving your execution of each lift and the ability to get the greatest stimulus possible out of a single set. This is a skill that will set you up for success in the subsequent phases.

Another key element of a primer phase is addressing muscle imbalances and weak links. One of the factors that often holds back muscle-building progress is that a weak link in the chain prevents you from being able to fully challenge bigger, stronger muscles. If those muscles are not fully challenged, they never fully develop.

By building stability, structural balance, and strength in the end ranges (fully lengthened and fully-shortened positions), you can manage your injury risk and open up a bigger window of opportunity for muscle mass gains.

A primer phase literally primes you for growth and is usually 4 weeks long and includes 4 sessions per week.

Building Phase

With firm foundations in place, it is time to build on them. You can now capitalize on the groundwork you have done by using your primer phase as the launchpad into a productive building phase. It is during this phase that you will see radical improvements in your physique. These changes are possible because of what you have done in the primer phase.

By perfecting your motor patterns and the execution of your lifts, by learning to lock yourself into stable positions and maintain them as sets get hard, by strengthening weak links and achieving structural balance, you have built a robust body primed for the challenges ahead. You have also created the ability to get the most from the least. Making every set count. Every rep count. Now it is time to push the envelope and force the body to grow.

The programming structure of the building phase allows you to progressively overload via mechanical tension for 9 weeks. As the response to this stimulus begins to become muted and adaptive resistance rears its ugly head, the metabolic stress pathway is made the focus of your training.

In my experience, metabolic stress techniques are very effective but only for a short period of time. It appears they provide a novel muscle-building stimulus, but you adapt quickly to this. For that reason, I tend to keep this phase to 3 weeks.

Solidification Phase

Good things must come to an end. You can build a lot of muscle during a building phase, but it does not last forever. Eventually, your rate of gain will slow. The quantity of training required to keep forcing the body to grow becomes unsustainable and you will reach a natural conclusion to this phase of training. This is largely due to the principle of adaptive resistance I explained earlier.

As a consequence, it is not possible to run a building phase indefinitely. Doing so eventually becomes a case of banging your head against a brick wall. This is not to say that you will never build more muscle. It is simply that at this moment in time trying to force more muscle gain will not yield good results. If, however, you are intelligent about things you can consolidate the muscle mass you have built so far and create a platform to build more.

Doing so requires what I call a solidification phase.

During this phase, you solidify your gains, build strength, reduce fatigue, and increase your potential for more muscle gain. Should you decide you have built enough muscle mass to want to enter a cutting phase to reveal your physique then, this solidification phase is also a vital stage in your success.

The solidification phase is essentially a low-volume strength block.

If you want to build more muscle, the solidification phase works by allowing you to increase your strength levels, reduce overall fatigue, get a different psychological training focus, and re-sensitize to the benefits of the training you did in the building phase.

If after the building phase, you want to cut down to display your new more muscle physique, the solidification phase also serves a vital role.

All too often guys bulk up and then immediately transition to an aggressive and restrictive diet that puts them in a significant calorie deficit. When they do this they usually hemorrhage muscle. The final few pounds they built in the building phase disappears overnight. By taking a solidification phase it allows you to “own” the new higher body weight. You adapt to the “new normal” and the body begins to recognize it as its new settling point. Thus, when you cut down after a solidification phase, you retain all the muscle you built.

The lower volume strength-focused work of a solidification phase also has the benefit of meaning you are more responsive to the style of training most suited to effective cutting. Incidentally, that style of training is extremely similar to what builds muscle. Think of it this way, what built it best, keeps it best.


That is the rationale and overview of the P.B.S. model for maximum muscle mass. In my follow-up articles, I’ll provide more detail and specific examples of how to program each phase. If you have hit a plateau in your muscle-building journey and aren’t certain what changes to make to kick-start your progress then I think the P.B.S. approach is the solution. Make sure to check out my next article on how to design a primer phase.

The Primer Phase: Part 1 of the P.B.S. Model

Posted on: Fri, 09/03/2021 - 13:04

thanks for sharing such an amazing information.

Posted on: Wed, 06/22/2022 - 06:21

Thankyou for sharing such an amazing information , I really need this , It will really helpful for me.
I really likes your blog ,it always gives me amazing knowledge about health and nutrition.
big thanks to you to understand our health problems and suggest best way to fix them.

Posted on: Tue, 06/08/2021 - 01:28

Hey guys, is there already a plan for this to work with? The theory behind it sounds awesome.

M&S Team Badge
Posted on: Tue, 06/08/2021 - 09:43

Hey Martin - this is a multi-part series here on the site with a new piece each month! We just published the primer phase last month. Check it out here:

Posted on: Sun, 05/02/2021 - 13:26

Is there an actual model workout of this technique to follow? I don't have the knowledge to put one together myself, but would love to try this method.

M&S Team Badge
Posted on: Mon, 05/03/2021 - 09:47

Hey Jay - the workouts will be coming soon so stay tuned!

Adrian Gamory
Posted on: Sun, 05/02/2021 - 12:30

Great article. You have my attention. Looking forward to the exercise details on the phases.