Everything you need to know about how to build muscle.
In 1985, one of the all-time great training montages in cinema history hit theaters.
It had everything.
The United States was up against the Soviet Union during the heart of the Cold War. Old school grit and determination against new age science. It had revenge, a killer soundtrack, and above all else, it had muscle.
Of course, I am talking about Rocky 4.
If you are unfamiliar with the series, in this installment, Rocky goes up against the Soviet killing machine, Drago. Both guys are in phenomenal shape, and it is on full display. There are over seven minutes of testosterone-fueled training scenes.
Man, they don’t make movies like they used to.
As a kid, I probably watched that movie a hundred times. Although I didn’t know it at the time, it planted a seed in my head at an early age. I wanted to learn how to build muscle. Some kids have superheroes; I had Sly Stallone.
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Why Building Muscle is Important
Building muscle is a fascinating topic.
Gaining muscle benefits everyone, from pro athletes to your grandmother. Increasing muscle size is the key to improving body composition, strength potential, athletic performance, health, longevity, and more. Building muscle goes well beyond just bodybuilding.
With that said, the aesthetic component of building muscle is a prime motivator for most people.
Even a few extra pounds of lean tissue can transform the look of a physique. When people say they want to be “fit and toned,” they mean, “I want to be lean and muscular.” It’s impossible to shape fat, and you can’t flex what’s not there.
Impact on Strength
The relationship between building muscle and gaining strength is a popular topic.
Multiple factors contribute to muscular strength, and muscle size is one. Building muscle does not necessarily increase strength linearly, but a larger muscle has the potential to be a stronger muscle. A new study on powerlifting performance found that “A combination of experience, fat mass, and upper-limb and lower-limb muscle mass indexes can accurately and precisely predict overall and individual lift performance” [1].
There is a strong relationship between muscle mass and powerlifting performance. Of course, this is not anything we didn’t know, but it’s nice to have actual data.
If you look at the podium at big meets, the best lifters generally are the most muscled in the weight class. To be the best lifter you can be, some of your training needs to focus on building muscle.
The same can be said for other athletic pursuits as well.
We know that the best sports-specific training is performing the sport or movement you compete in. The next best thing is training, which maximizes the specific adaptation you are trying to improve. Building muscle is worthwhile if size or strength plays a role in your sport.
Principle of Overload
No one likes change.
We are all creatures of habit. It’s ingrained in us at the cellular level. Think back to middle school biology. Remember homeostasis?
Homeostasis is simply a state of balance among all systems needed for the body to function correctly. Body temperature, blood pressure, and fluid balance are examples of homeostasis. If the body senses any changes to these measurements, it takes action to return to balance. It’s why we shiver when cold and sweat in the heat.
When subjected to anything beyond normal conditions, the body is forced to produce an adaptive response to maintain homeostasis.
The muscles are no exception.
Stimulus, Recovery, and Adaptation
The science of building muscle can be described as a three-step process of stimulus, recovery, and adaptation. The process starts in the gym with a workout. Next, the recovery systems heal and rebuild the damaged tissue. Lastly, after the tissue is healed, adaptation occurs. Although lifting weights gets everything started, it’s not until the entire process of stimulus, recovery, and adaptation progress is made.
Training must challenge and stress the muscles beyond their current ability. This is what stimulates adaptation.
The body adapts to stress by growing and getting stronger. If presented with the same stimulus again, it won’t be a challenge, and homeostasis can be maintained.
But you are smarter than that.
Next time, you up the ante by adding five pounds, doing another set, or completing an extra rep or two. This is progressive overload. The concept is that training must get progressively more challenging over time to continue stimulating adaptation.
Progressive overload does not need to occur in every training session. Beyond the beginner and early intermediate stages, this is unrealistic. However, if you do not add weight to the bar over time, you will not grow. You don’t always need to beat the logbook, but you should always be trying to.
The Role of Mechanical Tension
Mechanical tension is the stress applied to a muscle from external resistance, which is widely considered the primary factor in muscle growth.
An extreme example of how fundamental tension is to our musculature is what happens to astronauts in space. Although we don’t realize it, gravity always applies tension to our muscles. In fact, we must constantly support ourselves against the force of gravity.
Very little muscle contraction is needed when astronauts are up in a weightless environment. According to NASA, astronauts experience up to a 20% loss of muscle mass during spaceflights. Without a tension stimulus present, extra muscle mass is obsolete.
How does this apply to getting jacked?
Without a progressive training stimulus, we only have as much muscle as we need to perform daily functions. Picking up boxes, lifting our kids, and even walking are examples of hypertrophy stimulus, just a minuscule amount.
To grow additional muscle beyond what is needed for daily functions, we must introduce the body to higher levels of mechanical tension.
Motor Units and Muscle Fiber Recruitment
Before we move on, we need a brief and simplistic view of motor units and muscle fiber recruitment.
A motor unit is a motor neuron and a group of muscle fibers. There are several hundred muscle fibers bundled together in a single motor unit. There are two main types of muscle fibers – type I and type II. Type I muscle fibers are typically smaller, generate less fatigue, and fatigue slowly. Type I fibers are great for endurance activities. They are classified as slow-twitch.
Type II fibers are typically larger, generate more force, have more potential for growth, and fatigue quickly. Type II fibers are better for high-intensity activities like lifting weights. They are classified as fast-twitch.
A motor unit is composed of muscle fibers of the same types. So motor units can also be classified as slow twitch and fast twitch.
Henneman’s Size Principle
According to Henneman’s Size Principle, motor units are recruited according to the magnitude of their force output as more force is needed. Small units are recruited first, followed by larger units.
Mechanical tension is detected at the muscle fiber level, not the whole muscle. So during activity, the muscle fibers are recruited from smaller type I fibers to larger type II. As force requirements increase, type II fibers are recruited more.
With this in mind, there are two ways to recruit all muscle fibers maximally: lift heavy weights or light weights close to failure.
Lifting heavy weights (above 80-85% of 1RM) generates high force right from the start. For example, doing a set of 5 with 85% will be five high-tension and demanding reps. The other option is to lift lighter weights but push the set hard. Mechanical tension increases the closer you get to failure, regardless of the load.
For example, if you bench press a weight you can lift 20 times, the first few reps will be low tension and easy. However, as you continue, tension will increase. By the last few reps, mechanical tension will be high enough to elicit the high threshold motor units.
This explains why research shows muscle growth can occur across a spectrum of loading and rep ranges [2]. More on this when we dig into the relative effort, intensity and load.
Mechanical tension outlines the acute response needed to build muscle. When performing a set, we must push ourselves hard enough to activate as many muscle fibers as possible. However, that is only part of the story.
How to Build Muscle: The Training Variables
So far, nothing we have gone over provides any direction for how we should train to build muscle.
We know we need to work hard and challenge the muscles beyond their capability. But, just doing challenging exercises does not guarantee muscle growth. The next step is ensuring our training is specific to muscle building.
The principle of specificity states that the results you get from training are specific to the type of exercise you do. Building muscle comes down to manipulating the training variables to facilitate muscle growth best.
Volume
Volume is the total amount of work you perform over a given time.
There are a few different ways to quantify it. Volume can be expressed as volume load or tonnage (sets x reps x weight). Another option is repetition volume, calculated by the number of reps performed (sets x reps). Or my preferred method, set volume. This is determined by the number of total sets done for a given exercise or muscle group.
Set volume gives us the best representation of the training response generated because there is a dose-response relationship between sets performed and hypertrophy. This means that doing multiple sets of an exercise leads to more muscle development than doing just one [3].
How much total volume do we need?
In a 2017 meta-analysis, Schoenfeld and colleagues wrote: “Based on our findings, it would appear that performance of at least ten weekly sets per muscle group is necessary to maximize increases in muscle mass” [4].
Although there is a range of individual differences, ten sets per muscle group per week is a good starting point. From there, add additional volume as needed.
How Much Volume Is Too Much?
I know what you might be thinking. If volume is critical in building muscle, why start at ten weekly sets when I can jump to twenty or thirty?
The muscle-building response to training volume follows an inverted “U” shape curve. Progress increases with added volume until it peaks and starts to come down. In other words, more work leads to better progress until it doesn’t.
The optimal amount of volume will be different for everyone. It also varies between muscle groups and is not static. The amount you need to make progress goes up slightly over time.
This is where individual differences come in. Determining the right volume can be tricky and often requires trial and error. The consensus is to cap volume around 20 sets per muscle group weekly.
What About Ancillary Volume?
Compound exercises train more than one muscle group. For example, the biceps, triceps, and delts receive substantial stimulation on rows, pull-ups, pulldowns, and presses.
The problem is it’s hard to quantify how much stimulation the ancillary muscle receives.
Some people count indirect volume as equal to the direct volume in a one-to-one ratio. In reality, it is probably closer to a half-set. However, I don’t recommend counting it towards weekly volume for simplicity. It can get too messy.
Let’s say you do five sets of bench presses. Of course, it counts toward the chest, but what about the triceps and front delts? Do we count 2 or 3 sets for those muscles as well? Or, since the triceps are more involved than the delts, the triceps should count for 2.5, and the delts should count for only 1 set.
I look at it this way because compound exercises stimulate the secondary muscles indirectly. We can get away with less direct volume for the arms and shoulders.
Relative Effort and Intensity
Now that we know how many sets we need to build muscle, what counts as a set? As we learned in discussing mechanical tension, a set needs to be challenging to be effective.
Training to failure was once thought to be essential to building muscle and gaining strength. But that’s not necessarily the case. Over the past few years, research has shown there’s not much difference between training to failure and stopping just shy.
To understand relative effort, we need to look at intensity.
Intensity can be defined and implemented as the intensity of load or effort. The “intensity of load” refers to the percentage of a one-rep max or training max, whereas the “intensity of effort” refers to how near maximal effort the load is, represented by a rating of perceived exertion (RPE) or reps in reserve (RIR).
To get the most out of training, you must ensure your working sets are close enough to fail to produce a lot of muscle tension.
Intensity Discipline
If you are not mindful of intensity, working sets will get further from failure without realizing it. Even experienced lifters can get comfortable and lose the ability to gauge RPE/RIR. I find myself going over this with clients a lot. Don’t go into autopilot. At the end of a set, ask yourself, “If I absolutely had to, how many more reps could I have gotten with good form?”
It helps to know what muscular failure is and feels like to get a good handle on RPE and RIR. To prevent a lack of intensity discipline, periodically program sets to failure. I use AMRAP sets and 10 RPE / 0 RIR top sets to recalibrate myself and my clients to the scale. Advanced lifters must push it closer to failure more often than beginners or intermediates.
The ability to gauge failure is movement specific. Accurate ratings on the squat or deadlift don’t necessarily translate to a dumbbell side raise. This is something you need to do for most exercises.
You can use the RPE scale or repetitions in reserve (RIR) to quantify relative effort. Below is a basic rundown of both.
The RPE Scale
1-4: Very light to light effort. Warm-up weight.
5-6: Light effort, could do 4-6 more repetitions.
7: Speed was fairly quick, could have done 3 more reps.
7.5: Could definitely do 2 more reps, maybe 3.
8: You could have done 2 more reps.
8.5: Could definitely do 1 more rep, maybe 2.
9: You could have done 1 more rep or more weight.
9.5: Could not have done more reps, could do slightly more weight.
10: Absolute maximal effort. No more weight or reps are possible.
Reps in Reserve
0 RIR = 0 reps shy of failure, could not do any more reps.
1 RIR = 1 rep shy of failure, could do one more rep.
2 RIR = 2 reps shy of failure, could do two more reps.
3 RIR – 3 reps shy of failure, could do three more reps.
4 RIR – 4 reps shy of failure, could do four more reps.
To maximize muscle development, we want to focus on sets of 6 and above on the RPE scale. Or between 0 and 4 RIR. Sets too far from failure will not challenge the muscle enough to facilitate muscle growth. This is why warm-up sets don’t count towards weekly volume.
Determining Load and Rep Range
In old bodybuilding or even physiology books, the hypertrophy rep range is typically 8-12. When I first started lifting, 8-12 was widely considered the ideal rep range for building muscle.
It wasn’t until recently that research began challenging this notion. Research shows that muscle growth can occur across a spectrum of loading and rep ranges [2]. Low and high repetitions stimulate hypertrophy just as well as moderate repetitions so long as the volume is matched and the sets are taken close to failure.
In a now-famous study, Schoenfeld and colleagues compared the muscle-building effects of a bodybuilding type program and a powerlifting type program. It was set up as 3 sets of 10 and 7 sets of 3, respectively. The results were pretty interesting. They found both training styles resulted in similar increases in muscle size [5].
However, it was not that simple.
I love lifting heavy, but there is a reason bodybuilders don’t train like powerlifters. It takes considerably longer to do 7 sets of 3 than 3 sets of 10. The bodybuilding group in the study finished in about half the time. In this scenario, they could have moved on and done another exercise or two before the powerlifting group finished.
Additionally, powerlifting training beats up the joins. Many subjects reported joint pain, and a few had injuries. Lifting heavy weights in a low rep range is necessary to be as strong as possible. But it is not the best way to build muscle.
What About Really High Reps?
If volume is adequate and effort is high, you can still build muscle using light weights. However, if you have ever done a set of 30 reps to failure on the leg press, you know how unpleasant an experience that can be.
In a 2019 study, researchers investigated the effects of different training loads on ratings of perceived exertion, discomfort, and feelings of pleasure/displeasure. They compared sets of 8-12 reps against 25-30. The research showed resistance training performed with a light load (25-30 reps) until failure induces higher degrees of effort, discomfort, and displeasure compared to a moderate load (8-12 reps) [6].
Now, just because high rep training is uncomfortable doesn’t mean we should avoid it. There is a time and place to occasionally push reps above 20. However, we don’t want to make our training excessively unpleasant. Enjoying your training is often more important than we give it credit for. Also, with higher reps, it’s more challenging to gauge failure.
This brings us back to the idea of a hypertrophy rep range.
In a practical sense, 6-20 reps are the sweet spot. When the goal is building muscle, it makes sense for the majority of training to be in this range. It’s time-efficient, less taxing on the joints, and more enjoyable. Plus, it still gives us the ability to touch some heavy weight and pump out a ton of reps. It’s the best of both worlds.
Frequency
Training frequency is an interesting topic.
In the context of building muscle, frequency typically indicates the number of total training sessions or the number of times a muscle group is trained per week.
High-frequency training programs (training muscle groups more than once a week) were the general consensus until the 1990s. However, in the 90s and 2000s, as volume recommendations came down, so did training frequency. This gave rise to Bro Splits, which gave each muscle group its own dedicated day.
As with most things in fitness, what is old, becomes new again.
As evidence-based fitness took hold in the 2010s, a pushback against bro splits emerged. Training each muscle group multiple times per week became popular again.
Although high-frequency training is often seen as evidence-based, training frequency does not significantly or meaningfully impact muscle hypertrophy when the volume is equated [7]. Simply put, it doesn’t matter if you train each muscle once per week or three times per week. When the volume is the same, muscle growth is equivalent.
Therefore, frequency can best be described as a way to distribute weekly volume.
How Much Volume Can You Do In One Workout?
Let’s go back to our discussion on volume. We know most people need between 10 and 20 weekly sets per muscle group per week to maximize muscle growth. Although the research is unclear, there does seem to be a cap on how much volume per muscle group is effective in one training session.
In practice, 6-12 sets per muscle group are the ideal range for training in a single training session. Doing excessive volume for one muscle group in a training session leads to diminished intensity and motivation to continue training hard towards the end of the workout.
If you are an upper-intermediate or advanced lifter doing 15-20 sets per muscle group per week, it makes sense to break that up into two training sessions per week.
Keep in mind there is no single perfect training frequency. Hitting each muscle twice or three times per week is not necessarily better than once a week. The right approach will come down to your daily schedule and volume needs.
Reverse engineer it.
Start by looking at your schedule. Determine how many days you can get to the gym. Next, lay out how much volume you need for each muscle group. Then, organize your weekly training split for the best performance and recovery combination.
Rest Periods
Rest time between sets is one of the most common questions I get asked.
Short rest periods were recommended for a long time when training for hypertrophy. But, research has recently shown an advantage to extended rest periods [8]. In terms of performance, this makes sense.
When using high fatiguing, compound exercises like squats, bench press, overhead press, rows, and deadlifts, short rest intervals limit subsequent set performance. For example, if you do a set of 10 close to failure on squats and try to go again after only a 60-second break, it would be almost impossible to do another set of 10. On the other hand, after 3-5 minutes, repeating the first set performance would be manageable.
With that said, most of us don’t have to be in the gym all day. On single-joint exercises, we can get away with shorter rest periods.
My practical recommendations for rest periods are pretty simple. Rest long enough until you feel ready to perform at your best on the next set. For compound exercises, that is likely to be 2-5 minutes. On smaller, single-joint isolation exercises, 1-2 minutes will suffice.
Exercise Selection
Exercise selection is the ultimate dichotomy.
Setting up a well-designed training routine is a battle between too much and not enough variation. People have long thought exercise variation was a key component of building muscle. The idea was you had to “confuse the muscle” for it to grow.
From a logical standpoint, it makes sense.
Unfamiliar exercises generally produce extra soreness, making them seem more effective. However, soreness is not 100% indicative of building muscle. If it were, long-distance running would be a great way to build your lower body, especially if you are not used to it.
Most People Change Exercises Too Frequently
The problem with changing exercises too frequently is it makes it hard to track progress. Remember, progressive overload is a piece of the puzzle. If you are always doing new exercises, how do you measure progress? You might overload the muscle progressively, but it would be difficult to know.
The most effective training programs involve the same basic exercises repeated consistently and progressively over time.
With that said, no single exercise can effectively maximize the development of an entire muscle group. To maximally develop your chest, you need more than just the bench press. The same thing goes for your quads. Squatting alone is not enough.
To achieve full development, you must vary exercise selection enough so muscles are worked from multiple angles.
Using a mix of exercises for each muscle group ensures complete stimulation of all muscle fibers. Plus, variety is the spice of life. How many dumbbell curls can you do before getting tired of it and joining a CrossFit gym? Sometimes just adding in a new exercise can give you an added jolt of enjoyment to push harder during your workouts.
Advanced Training Techniques
Advanced training techniques have been widely used in bodybuilding circles for decades.
Although many competitors swear by them, none of these techniques will make or break your progress. In fact, you could never do advanced training techniques without any ill effects on your progress.
With that said, supersets, drop sets, and Myo Reps can be part of quality programming if used correctly. The biggest benefit comes down to time efficiency and preventing monotony.
Supersets
My favorite intensity technique is the superset. I have been a fan of these since reading about them in Arnold’s Encyclopedia of Modern Bodybuilding back in the day.
A superset is when you do two sets of different exercises back to back. The most effective way to do this is using antagonist paired sets, also called the agonist-antagonist superset.
With an agonist-antagonist superset, you pick movements that oppose each other. For example, a set of bench presses followed by a set of dumbbell rows. Or a set of triceps extensions followed by a set of biceps curls. The second exercise works the opposite muscle group from the first.
This is the best method to save time without negatively impacting performance. Let’s go back to the triceps extension and biceps curl example. When you move from the extensions to the curls, you work your biceps while the triceps rest.
This is the way to go if you want to get more work done in less time but don’t want to compromise performance.
Drop Sets
When I think of supersets, I think of Arnold. When I think of drop sets, I think of Dorian Yates.
Drop sets are when you do a set close to failure with a given load, and with minimal rest, perform as many reps as possible with reduced weight. Drop sets are a way to get in more high fatigue reps in a short time.
There are many different ways to set them up. I prefer one drop in weight, between 20-30%, and having a minimum number of goal reps to achieve.
For example, let’s say you are doing a set of dumbbell side raises with 30 pounds. You do 10 reps close to failure and immediately drop the weight to 20 pounds. A good goal would be to do at least 5 reps with 20 pounds.
I like drop sets because they push you beyond your comfort zone. It’s hard to quantify volume with drop sets, but they should only make up a small part of the program so it’s not a big deal. Since the drop set is often taken to failure, limiting them to the last set of an exercise is best.
Myo Reps
The last advanced technique I want to talk about is Myo Reps. Myo reps are a variation on rest-pause sets created by Borge Fagerli.
From Borge, “Myo-reps is, simplistically speaking, a rest-pause method, and the most famous permutation of it is DC/Doggcrapp training. Most of you probably know how to perform a rest-pause set, and I didn’t just reinvent the wheel here, I refined it building on research on hypertrophy in recent years.”
Myo Reps are best done with assistance movements. My favorites are barbell curls, dumbbell side raises, triceps extensions, and various machine exercises. I also find they work well with bodyweight movements as well.
To perform Myo Reps, start with a traditional set in the 10-20 rep range taken close or to failure. This is called the activation set. From there, rest briefly (3-5 big breaths) and do another set with the same weight. This is called the Myo Reps. Since the rest time is limited, the goal is only to do 20-50% of the reps completed during the activation set. Rest another 3-5 big breaths and do another set. Complete 3-5 rounds of Myo Reps.
How to Do Myo Reps
Activation set = 1 set x 10-20 reps @0-1 RIR
Rest 3-5 big breaths between sets [5-15 seconds]
Myo Reps: 3-5 sets x 3-5 reps or 25-50% of Activation Set with the same weight
Myo reps are similar to drop sets in they increase the number of high fatigue reps in a short period of time. Again, these should only make up for a small part of the program. I recommend limiting them to the last exercise of the training session.
Bringing It All Together
Building muscle is a complex topic. However, the best practices are pretty simple.
Do enough volume, but not too much. Hit each muscle once or twice a week. Keep most of your sets in the 6 to 20 rep range, and push each set close to failure. You don’t always have to beat the logbook, but you should always try. Rest long enough between sets to not have to drastically decrease the load from set to set. Remember to hit each muscle from a variety of angles. Lastly, occasionally, throw in some advanced techniques to keep things interesting.
References:
- Ferrari L, Colosio AL, Teso M, Pogliaghi S. Performance and Anthropometrics of Classic Powerlifters: Which Characteristics Matter? J Strength Cond Res. 2022 Apr 1;36(4):1003-1010. doi: 10.1519/JSC.0000000000003570. PMID: 32187154.
- Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW. Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. J Strength Cond Res. 2017 Dec;31(12):3508-3523. doi: 10.1519/JSC.0000000000002200. PMID: 28834797.
- Radaelli R, Fleck SJ, Leite T, Leite RD, Pinto RS, Fernandes L, Simão R. Dose-response of 1, 3, and 5 sets of resistance exercise on strength, local muscular endurance, and hypertrophy. J Strength Cond Res. 2015 May;29(5):1349-58. doi: 10.1519/JSC.0000000000000758. PMID: 25546444.
- Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis. J Sports Sci. 2017 Jun;35(11):1073-1082. doi: 10.1080/02640414.2016.1210197. Epub 2016 Jul 19. PMID: 27433992.
- Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Sonmez GT, Alvar BA. Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. J Strength Cond Res. 2014 Oct;28(10):2909-18. doi: 10.1519/JSC.0000000000000480. PMID: 24714538.
- Ribeiro AS, Dos Santos ED, Nunes JP, Schoenfeld BJ. Acute Effects of Different Training Loads on Affective Responses in Resistance-trained Men. Int J Sports Med. 2019 Dec;40(13):850-855. doi: 10.1055/a-0997-6680. Epub 2019 Sep 9. PMID: 31499564.
- Schoenfeld BJ, Grgic J, Krieger J. How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. J Sports Sci. 2019 Jun;37(11):1286-1295. doi: 10.1080/02640414.2018.1555906. Epub 2018 Dec 17. PMID: 30558493.
- Grgic J, Lazinica B, Mikulic P, Krieger JW, Schoenfeld BJ. The effects of short versus long inter-set rest intervals in resistance training on measures of muscle hypertrophy: A systematic review. Eur J Sport Sci. 2017 Sep;17(8):983-993. doi: 10.1080/17461391.2017.1340524. Epub 2017 Jun 22. PMID: 28641044.
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