The Smart Science Behind Muscle Growth

By Luke Briggs

Stronger, Leaner, Healtier, FOREVER

Introducing Functional Strength Training: 
The Monthly Membership Training Solution For People Who Want To Look, Feel And Function Their Very Best, Forever.

Join FST NOw

Stronger, Leaner, Healtier, FOREVER

Introducing Functional Strength Training: 
The Monthly Membership Training Solution For People Who Want To Look, Feel And Function Their Very Best, Forever.

Join FST NOw

Enough with this “hardgainer” mentality people. There is a reason why the vast majority of people, both male and female, have a damn hard time putting on lean muscle mass and taking their bodies to the next level, and sometimes end up flabby and soft in the process. Time to tap into your muscle growth potential.

Hypertrophy isn’t achieved through random acts of strength training alone as most assume. The mechanism of hypertrophy is actually one of the more complicated muscle adaptions in all of sport and fitness.  This week we have Luke Briggs back on JRx dispelling muscle building myths, and laying down what exact variables need to be addressed to pack on a little muscle armor.

Here’s What You Need To Know…

1. Training just isn’t as simple as lifting some weights and calling it a day. Specific programs and techniques are needed to target strength, athletic performance and maximal hypertrophy that may contradict one another.

2. If you want to increase your muscle mass, the answer is simple…start to train like a bodybuilder. That’s what increasing muscle mass is at the end of the day, stop lying to yourself and buy in.

3. While there are three main mechanisms of muscle growth, many other training and lifestyle variables like training age, recovery and frequency are important to create an anabolic environment for lean muscle.

4. Figuring out your perfect blend of frequency, intensity and overall volume of your training is the key to building muscle and achieving a solid physique in the most time efficient way possible.

So you want to get huge, huh bro? Yeah, so does every wannabe Instagram shredder dude and booty chick.  Well here’s the big question for you before we even dive into the amount of supplements and pharmaceuticals it’s going to take to get you there; How many days per week should you be training?

Bodybuilding superstars like Phil Heath and Kai Greene train pretty much every day. Some physique athletes have been known to train two or three times per day, but as a non-genetic mutant freak, should you be lifting that frequently like these superstars?

You need to first understand the amount of training an individual can handle is highly dependent on a number of variables including recovery, nutrition and training age. These are non-training requisites that need to be accurately defined to have any chance of success in the muscle game.

If you eat like garbage and sleep only five hours a night, you’re probably not going to be able to handle a very high workload. You can’t out train a shitty diet, and if muscle is your goal, you absolutely can’t pack on lean mass eating just twigs and berries and claiming hardgainer syndrome as the definitive diagnosis.

Lets be honest, if you can’t take control of your eating habits, sleep cycles and other simple variables like drinking a damn glass of water, you’ve got bigger things to worry about than the number of days per week you should lift.

Before we go any further, we need to first distinguish the difference between training for strength or athletic performance and training for muscle growth. These separate but synergistic forms of training are widely misunderstood, and a primary reason for many unachieved goals.

What’s The Different Between Training For Strength and Training For Muscle?

skinny guy exercises

If your goal is maximum strength, there’s no question you should avoid body-part splits. After all, how is spending entire days working your arms or shoulders going to maximize your strength or speed?

Strength routines involve predominantly compound exercises, so you need more recovery time from both mechanical and neurological aspects of regeneration. Most successful strength-based programs call for three or four full-body workouts per week. You’ve got to take long rest periods between exercises to allow your central nervous system to recuperate. Simple stuff here, people.

You need to focus on pristine form to create tension during muscle-building routines, but when pushing maximal weight, form oftentimes goes out the window.

Can you build muscle performing a strength-based routine? Absolutely. Much of it depends on your nutrition. If you want to add muscular size, you’ve got to be in a positive energy balance even if you are ingesting $238 of supplements daily. If you want to maintain or even lose weight, you’ve got to burn off the same or more calories than you consume.

If you’re looking to compete in a field or court sport, bodybuilding-style training isn’t the most ideal specialty form of training, but holds some merit in more advanced programming.

But if you’re either a physique competitor or a meathead looking to get big, you’re not going to be able to maximize your muscular potential performing a strength-based routine. Why’s that?

Well, let’s discuss the three factors responsible for muscle growth.

Top 3 Training Factors For Muscle Growth

In 2010, Brad Schoenfeld authored one of the most well-respected publications outlining the variables associated with muscle hypertrophy. He deduced three primary elements influenced the increase of lean body mass the most (Schoenfeld, 2010).

#1 Mechanical Tension

muscle growth

Widely considered the most important factor for muscle growth, the amount of tension you place on your muscles has a massive anabolic effect. Take a weight through its full range of motion, and your results will accelerate even more.

Now, you don’t need to lift as heavy as possible to maximize tension. You’ve just got to stress the muscles enough to disturb their integrity. Ever wonder why bodybuilders are more muscular than powerlifters even though they don’t lift as heavy? Case in point.

Tension is also one of the hardest muscular mechanisms to master, thus why we see strength and power athletes continuing to improve further and further into their careers. Tension is as much as skill as it is a form of producing and maximizing brute strength.

#2 Muscle Damage

squat hypertrophy

Being sore after a workout can actually be a good thing for hypertrophy. Now, let’s be honest – killing yourself every workout isn’t a good thing because it could potentially lead to overtraining or injury. We’ve all been there in our lifting careers, and most of us have gotten more intelligent with our programming over the years. But if you push yourself to the point of soreness every once in a while, you can reap the benefits of muscle damage.

You know how you’re usually the sorest a day or two after an intense workout? Delayed-onset muscle soreness (DOMS) is caused by microtears to muscle tissue. The body releases immune cells to the damaged tissues, leading to a growth response that strengthens the muscle in the event a future stress of that nature is placed on the tissues.

This mechanism is great if you can recover before your next training day, but can come right up and bite you in the ass if too much micro trauma accumulates and forms macrotrauma to the body’s tissues. Time to go see Dr. John Rusin for a consult if you find yourself in this state.

#3 Metabolic Stress

biceps curl metabolic stress

Just like Arnold said, you’ve got to chase the pump. On a side note, no article on muscle building is complete without a quote from Arnold, just saying.

You know that burning sensation you get when you perform a lot of reps in a row? Your body produces metabolic waste products such as lactate and hydrogen ions that lead indirectly to cell swelling, an important phenomenon in muscle growth. That’s why adding intensifiers like drop sets and rest-pause sets can be beneficial for hypertrophy.

RELATED: Maximizing Metabolic Stress with Intensity Techniques For Hypertrophy

You won’t find too much of this type of training in an methodically programmed strength or athletic performance regimen because getting a “pump” too often will only slow you down.

What Causes Muscles To Grow?

muscle growth

According to muscle expert Brad Schoenfeld, muscle growth takes place only when a stress such as lifting a weight is placed on our muscles, pushing them past their current capacity. Our body prefers to maintain homeostasis, so we’ve got to create some sort of stress that leads to an adaptation (Schoenfeld, 2013).

Hans Selye first described General Adaptation Syndrome in 1950. A workout needs to have enough volume and intensity to cause overload, which leads to fatigue (the alarm phase). This leads to supercompensation, which is a positive adaptation (Rosenblatt, 247).

How long does it take to cause an adaptation?

Research varies, but protein synthesis can remain elevated at least 36 hours following a bout of resistance training, so you should probably wait at least two days, if not three, before training the same muscle group (MacDougall et al., 1995).

Before it becomes a question, I’m going to address it. No, don’t even think about bench pressing and curling every day, period. Everyone wants to know how much you can bench press, but you’re never going to get stronger if you don’t take some time off and let your muscles recover, bro.

You’ve also got to realize gender, hormones, biological age and genetics all factor into muscular potential.

Let’s face it – some people will naturally be able to put on more muscle mass than you. That doesn’t mean you should slack off and blame your genetics while weeping in the bathroom stalls of Planet Fitness. Keep working hard and good things will come. Bodybuilding is about building your ideal body, not idealizing someone else’s physique.

Training Age and Experience

training experience

Before you consider anything else, you’ve got to look how long you’ve been training to determine the number of days per week you should train.

According to the National Strength and Conditioning Association (NSCA), you’re considered a beginner if you’ve been strength training for less than two months, an intermediate lifter if you’ve been training for between two and six months and an advanced lifter if you’ve been training for at least a year (Baechle and Earle, 2008). Yeah, the NSCA may get a little heat for that because realistically what other skill can you “master” in just a year?

Based on your training status, the NSCA also recommends beginning lifters train two to three times per week, intermediate lifters train three to four times per week and advanced lifters train four to seven times per week.

Beginners especially can see massive gains training just a couple days per week. Because they’ve never really taken part in a serious workout regimen, they’ll grow just from getting stronger and overloading the musculoskeletal system and the neurological coordination and enhancement that comes with it.

But just because you’ve been lifting weights for a long time doesn’t mean you know what you’re doing in the gym.

If you’ve been lifting the same weight for the last five years and haven’t gotten much bigger, you’re probably still considered a beginner until you learn proper form and training methods. You know who you are!

If you’re not seeing any gains, maybe it’s time to check your ego and seek the help of a true professional that has earned the right to coach through battle tested years on the gym floor and enough testimonials to conclusively speak to their methods.

So throw away that cut-off t-shirt, quit spending half the workout checking yourself out in the mirror and get back to the fundamentals.

Full Body Training vs. Split Body Routines

full body training

So you shouldn’t train the same muscle group on consecutive days. That explains why many bodybuilders favor a split routine. They’ll have entirely separate days for chest, back, shoulders, arms and legs.

Research suggests upper-body muscles have a greater ability to recover more quickly than lower-body muscles, which is why you’ll rarely see bodybuilders schedule more than two legs workouts per week (Baechle and Earle, 2008).

If you’re going to perform full-body routines, you’re not going to be able to train every day because you need to allow for recovery. Athletes who train seven days per week use body-part splits. They’re always allowing ample time for individual muscle groups to recover.

You’ve also got to remember some of the top bodybuilders who train extremely frequently are aided by anabolic steroids and other performance enhancing drugs that the general public can’t even pronounce! Because of the chemical assistance, they’re able to recover faster between exercise bouts and add extra sessions each week. Plain and simple.

The Perfect Amount of Volume


How many sets and reps should you do? In other words, how much volume (total work completed) can your body handle?

Well, let’s dive right into that question.

First, you need to figure out what you’re doing outside the gym to determine the amount of work you should be doing inside the weight room.

If you’re participating in a sport, you’re not going to be able to handle as much volume in the weight room. Stress is stress, no mater what form it is being employed on the body.

If you’re not playing a sport, but you’re playing pick-up basketball four times per week and running an additional two times a week, don’t come complaining when you can’t put on any muscle mass. Stop doing so much cardio and focus on the weights.

If you’re a beginner in the gym, you won’t be able to perform as much volume as an intermediate or advanced lifter.

When considering your volume within a workout, you must also consider the type of muscle action being performed – concentric, isometric or eccentric.

RELATED: Know Your Contractions For Better Training and Programming

It takes a longer time to recover from eccentric work, so you’ll need to reduce volume if training sessions heavily emphasize the eccentric portion of the lift. You’ll be able to recover fastest from primarily concentric-based exercise.

According to Swedish researchers, if you’re a novice or intermediate trainee performing both the concentric and eccentric muscle actions for one or two seconds with one to three minutes of rest between sets, you should aim for one to three sets of eight to ten reps to failure or near failure per exercise. As you become more advanced, you should gradually increase the number of sets you perform (Wernbom et al., 2007).

The authors did admit most of their analysis revolved around short-term studies on untrained subjects, so take their recommendations with a grain of salt.

The NSCA suggests three to six sets of six to 12 reps for each exercise are sufficient for muscle growth (Baechle and Earle, 2008). Because the musculoskeletal system will eventually adapt to the number of sets you perform, you’ll need to eventually increase your sets with experience. And keep in mind, these reps are to absolute failure, not just throwing around pink dumbbells for six reps a set.

Based on your training status, between two and five exercises are typically performed per muscle group. If using a split routine, you can work between two and three muscle groups per day and perform up to 20 to 25 sets per muscle group each workout (Zatsiorsky and Kraemer, 2006).

The take home message: don’t try to do too much too soon. You’ve got to build intensity before volume.

Just The Right Amount of Intensity

squat intensity

For the sake of this discussion, let’s define intensity as the percentage of weight lifted relative to your one-rep max.

According to Swedish researchers who analyzed a wide range of data, intensity is best kept between 70% and 85% of your one-rep max, although they admitted hypertrophic gains can be achieved with both lower and higher intensities (Wernbom et al., 2007).

Many argue both through research and anecdotal evidence the most important variable in muscle growth for beginner and intermediate trainees is intensity, while research is still lacking for advanced athletes.

Unless you’re a world-class physique competitor, the fact is you’ll see awesome gains by just working on getting stronger, especially if your nutrition and recovery are on point.

When you step in a gym and watch the strongest lifters, do any of them look small? Absolutely not. While some may be more muscular than others, most strong lifters display a decent amount of size too.

Intensity is an important variable in muscle growth, but you’ve to make sure you don’t go too heavy each time in the gym. Athletes who work at higher intensities more often require more recovery time between training bouts and are more likely to breakdown when recovery ratios are off.

Real Life Factors and Time Devoted To Training

training time

You’ve got to assess the amount of time you can reasonably allocate to training. If you’re not going to be able to lift six days a week, don’t try to do it. If you have extensive work, social and familial obligations, you’re probably better off training less frequently but with greater intensity during each session.

If you’re a beginner, whether you’re training for hypertrophy, fat loss or strength development, you need to begin a full-body strength-training routine for probably no more than three days per week. You’ve got to work on progressively overloading your system by consistently adding weight to the bar to improve neuromuscular efficiency. Once you’ve built an adequate work capacity, you can begin to incorporate other methods and increase your frequency of training.

You’ve got to be honest with yourself. If you’re completely out of shape or have never trained before, don’t start with a program that calls for six body-split workouts per week. You haven’t built up enough strength yet and may hurt yourself if you go too hard too soon.

These workouts should take no longer than an hour. There’s no reason your workout should take two hours. Quit performing endless sets of biceps curls and playing with your phone. If your training plan hasn’t worked up until this point, it probably won’t.

A Note on Periodization and Programming For Growth

muscle growth periodization

You can’t kill yourself every time you’re in the gym, this should go without saying but I’ll review it again.

While a detailed overview on long-term organization of hypertrophy programs is beyond the scope of this article, just remember you need to have a plan each time you’re in the gym.

If you just do a bunch of random exercises every time you set foot in the weight room, you’re probably not going to get great results because you can’t really measure your progress.

When you train hard for long periods at a time, you need to make sure you lower the volume or intensity every so often.

You should also make sure you rotate exercises every once in a while because full stimulation of all muscle fibers enhances muscle growth (Schoenfeld, 2010).

Bottom line: always know what you’re doing ahead of time. Mix things up occasionally or when you stop making progress.

The Final Verdict For Effectively Stimulating Muscle Growth

If you’re a beginner, you’ll be fine with and probably benefit more from reducing training frequency and focusing more on recovery and nutrition to allow for adaptation to occur.

If you don’t eat or recover well, you’ve got to focus on nutrition and sleep first before concerning yourself with the number of days per week you should train. Focus on consuming whole, unprocessed foods with a caloric intake suitable to your goals while making sure you’re getting at least seven or eight hours of sleep per night.

Once you’ve got everything on point, start with three days per week of full-body exercises. Work on building up an appreciable amount of strength before adding workouts or increasing volume because hypertrophy is optimized when training with loads between 70% and 85% of your one-rep max.

Once you’ve reached intermediate status, increase your workload to four full-body workouts per week. When you become an advanced lifter, you’ll be able to handle anywhere between four and seven workouts per week. Consider using split routines at this point.

Once you’ve reached a highly advanced level, anecdotal evidence suggests performing split routines may be better for muscle gains. Just look at how all the top bodybuilders in the world train.

When using split routines, train two or possibly even three muscle groups per session. Perform three to six sets of each exercise between six and 12 reps. Use between two and five exercises per muscle group, depending on your level.

Understand these are general guidelines, and you may see spectacular results with much greater or much less volume and intensity. Experiment and do what works for you.

Be aware genetics, biological age, gender and hormonal status will affect muscular potential and training capacity.

You’ve also got to make sure you’re giving a good enough effort. If you’re wondering why you’re not seeing any gains, you’ve got to honestly assess whether you’re actually trying hard enough. You can follow a number of routines and see great results, but if you’re going to the gym and giving a half-hearted effort, you’re not going to get very far.

The principle of hard work has and will never change.

About The Author

luke briggs

Luke Briggs is a strength coach, powerlifter and former full time print journalist.  Luke is a Certified Strength and Conditioning Specialist (CSCS) through the National Strength and Conditioning Association who also holds a bachelor’s degree from the prestigious University of Wisconsin’s school of journalism. Luke’s vision is to help people around the world build muscle, burn fat, get stronger and become the best versions of themselves.  With his background in print journalism, he combines his writing skills, knowledge of fitness and personal training experience to be the best possible resource for you to reach all of your strength and physique goals.

Visit Luke at his:  Website: Luke Briggs Fitness                      Facebook: Luke Briggs


1. Baechle, Thomas R., and Roger W. Earle. Essentials of Strength Training and Conditioning. Champaign, IL: Human Kinetics, 2008. Print.

2. MacDougall, JD, MJ Gibala, MA Tarnopolsky, JR MacDonald, SA Interisano, and KE Yarasheski, “The time course for elevated muscle protein synthesis following heavy resistance exercise.” The Canadian Journal of Applied Physiology 20 (1995): 480-6. Web.

3. Rosenblatt, Benjamin. “Planning a Performance Programme.” High-Performance Training for Sports. N.p.: Human Kinetics, 2014. 247. Print. Muscle Growth

4. Schoenfeld, Brad. The Max Muscle Plan. N.p.: Human Kinetics, 2013. Print.

5. Schoenfeld, Brad J. “The Mechanisms of Muscle Hypertrophy, Muscle Growth and Their Application to Resistance Training.” Journal of Strength and Conditioning Research 24 (2010): 2857-872. Web.

6. Wernbom, Mathias, Jesper Augustsson, and Roland Thomee. “The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans.” Sports Medicine (2007); 37 (3): 225-264. Web. Muscle Growth

7. Zatsiorsky, Vladimir M. and William J. Kraemer. “Science and Practice of Strength Training.” N.p.: Human Kinetics, 2006. Print.

Related Posts


  1. Randy January 20, 2017 at 2:57 pm - Reply

    Very informative and well written article. Keep up the good work.

  2. George April 26, 2017 at 6:21 am - Reply

    Sorry not buying any of this crap the only thing that really works is the use of drugs and know it

    • Isaiah Stegall January 22, 2019 at 1:09 pm - Reply

      your a bitch.

  3. George April 26, 2017 at 6:23 am - Reply

    Sorry not buying any of this crap the only thing that really works is the use of drugs

  4. alpha male May 30, 2017 at 8:14 am - Reply

    great article! building muscle requires you to know how your body works. good nutrition and decent level of exercise ensures that your muscles gain weight. Eating proteins and doing regular exercise may be sufficient for many but there are others to find muscle building very hard. IMO if you are serious and dedicated to build muscle you will succeed!

  5. Matt Ross November 14, 2017 at 2:23 pm - Reply

    20-25 sets per muscle group / session seems overkill for natural trainees? I think the NSCA recommendations has been misinterpreted. For example, for intermediates it’s 3 times a week (when using full body) for 3-6 sets per exercice but it’s one exercice per muscle group so it’s total set per muscle group in reality.

    The range is then 9-18 sets per muscle group / per week not 20-25 per session.

  6. Isaiah Stegall January 22, 2019 at 1:32 pm - Reply

    girls write me at 2001 NE F St Grants pass OR 97526

    im lonely i need friends

  7. Jim Morrison February 5, 2019 at 1:07 pm - Reply

    Explain how dorian yates got so huge, only training 4 days per week and doing only 1 set to failure per exercise(not counting warmups). his style seems to fly in the face of guys training 6 days per week for 2 hours, doing endless amounts of sets…and yates has said, if doing more sets would have helped, he would have done it…since steroids increase recovery, why didn’t he train more often and do more volume??

    • John June 19, 2019 at 12:25 am - Reply

      Easy… steroids or genetics. Probably both. One outlier does not mean that his method works for everybody, especially a natural hardgainer. But yeah, sure, let’s just assume that because it worked for Dorian Yates that it’ll work for everyone.

  8. Tony November 1, 2019 at 10:16 pm - Reply

    Well organized article as if he is a former writer or something. Unfortunately, the substance is lacking.
    Bad ‘ holier than thow” attitude. The nerve to demean gym goers that are not training perfectly. Totally terrible for the industry.

    What ? Mention Olympia competitors but not gear.?? They don’t workout 7 days a week and recover bc they’re genetic freaks. Hello???

    You CAN eat like crap and make big gains. Ever heard of a dirty bulk, Bro? BTW Powerlifters are mostly fat guys. It is not as if they eat clean. See world’s strongest man contests.
    People try to make this activity complicated to justify their existence ( coaches, writers, youtubers).

    Train each muscle twice a week, 6-12 reps, 10-20 sets a week per group, shove plenty of protein in that hole below your nose, and sleep about 8 hours a night. You are good.

    Consistency is key.

  9. Fit Juggernaut November 19, 2020 at 12:28 pm - Reply

    Been training like this for years…have tried other methods in between but i think what you need to do is just works for you. Not everyone is the same

Leave A Comment