You want to know how to build muscle in the shortest time possible.
But, you’re confused by all the conflicting opinions about how to go about it.
One article says that you should do 6-12 reps per set, while another says that you’re far better off doing 4-6 reps per set.
Expert A says you should work different muscles on different days, while expert B says you should work your whole body three times a week.
You read a few articles on the subject of how to build muscle and think you’ve got it all figured out. Then you read something that says the exact opposite.
There’s conflicting advice coming at you from here, there and everywhere, and you can’t figure out who, or what, to believe.
How to Build Muscle: What the Science Says
The good news is that scientists have put many popular ideas about muscle growth to the test, from how often to train each muscle to the amount of time you should rest between sets.
As it happens, some of the advice that’s been floating around for years has turned out to be right, while some of it has turned out to be completely wrong.
Before I show you what the science says about how to build muscle, I do want to get a couple of things out of the way first.
Is It Hard to Build Muscle?
Gaining 20 or 30 pounds of muscle will involve a lot of hard work. Knowing how to build muscle is important, but by itself it’s not enough. You also need to be willing to put the work in.
While you can make visible changes to your physique in a matter of months, getting anywhere near your genetic ceiling in terms of muscle mass will require persistence and sustained effort over a period of several years. It’s not something you can do in 30 days, 12 weeks or even 12 months.
All of which brings me to point number two – how long will it take to build muscle?
How Fast Can You Gain Muscle?
The average guy, assuming he’s doing everything right, will take 3-4 months to gain around 10 pounds of muscle. However, results will vary from person to person. Some folks, despite training hard and eating right, will gain closer to 3 or 4 pounds over the same period of time.
And those numbers assume that you’re in your late teens or early twenties, have never lifted weights before, are training hard 3-5 days a week, and have all the right boxes ticked in terms of diet, sleep and recovery.
What if conditions are less than optimal? What if you’re 40 years old, eating a crappy diet, and haven’t had a decent night’s sleep since the Obama administration? If so, your muscles will take longer to grow, and you’ll need to adjust your expectations accordingly.
What’s more, muscle growth happens a lot faster when you’re a beginner. Over time, the speed at which you gain muscle will slow down.
That is, your first ten pounds of muscle might be gained in three or four months. The next ten pounds might take twice as long. And the next ten pounds will take longer still – think years rather than months.
Now that’s out the way, let’s dig in and take a closer look at what the science has to say on the subject of how to build muscle.
How Often Should You Train Each Muscle Group?
First up, we have the question of how often each muscle group should be trained.
Some say that the best way to build muscle is to bomb your muscles into submission once a week with lots of exercises, sets and reps.
A typical routine might involve chest on Monday, back on Tuesday, shoulders on Wednesday, legs on Thursday and arms on Friday. While some people get decent results with this type of routine, there are better options available.
In fact, working a muscle more frequently has been shown in a number of studies to increase the rate of muscle growth. In one trial, subjects who trained a muscle three times a week built muscle more quickly than the ones training it once a week 
When a team of scientists compared studies that investigated training muscle groups once, twice or three times a week, they concluded that “the major muscle groups should be trained at least twice a week” to maximize growth .
Why is hitting a muscle group twice a week or more a better way to build muscle than hitting it just once a week?
Protein synthesis – a key driving force behind muscle growth – is raised for a day or two after you train. But it’s back to normal a couple of days later . And simply creating more muscle damage doesn’t appear to make the rise in protein synthesis last any longer .
What’s more, the rise in protein synthesis after training peaks earlier and returns to normal more quickly in trained versus untrained individuals . The upshot of which is that there’s a smaller overall change in muscle protein synthesis in advanced lifters.
In other words, when you train a muscle group directly only once per week, the muscles might spend a few days “growing” after the workout. But if you leave an entire week between training each muscle group, you’re missing several additional opportunities to stimulate growth .
So, how many times should you train a muscle each week?
To gain muscle as fast as humanly possible, train each muscle 2-3 times a week. If you’ve got a few years of training under your belt, hitting each muscle up to five times a week can be very effective .
The first option is to train your whole body twice a week.
Monday: Whole Body
Thursday: Whole Body
I know that two workouts a week might not sound like much. But, as long as your program is set up right, you can still make decent progress lifting weights twice a week.
In fact, when Canadian researchers compared the same amount of training divided across two or three weekly workouts, gains in muscle size and strength were virtually identical with both routines .
Option two is a whole body workout performed three times a week on alternate days, normally Monday, Wednesday and Friday. Tuesday, Thursday and Saturday or Wednesday, Friday and Sunday will work just as well.
Monday: Whole Body
Wednesday: Whole Body
Friday: Whole Body
If you’re able to train 4-5 times a week, the number of effective routines on the menu becomes much larger.
Training more often means that you can divide your body into two or even three separate compartments, and still hit each muscle group twice a week or more.
Option three is to train four days a week using an upper/lower split. You hit the upper body on Monday, lower body on Tuesday, then take Wednesday off. Thursday is upper body, Friday is lower body and you have the weekend off. Each muscle group is trained twice a week. Of all the training splits I’ve used over the years, this one is my favorite.
Monday: Upper Body
Tuesday: Lower Body
Thursday: Upper Body
Friday: Lower Body
The fourth option is something called the push/pull/legs split. You train either four or five days a week, doing the pushing movements (chest, shoulders, and triceps) on Monday and the pulling movements (back and biceps) on Tuesday.
Then you take a day off before training legs on Thursday, followed by another day off on Friday. On Saturday you go back to the beginning and do the push workout again.
Day 1: Chest, Shoulders, Triceps
Day 2: Back, Biceps
Day 3: Off
Day 4: Legs
Day 5: Off
So you train for two days, take a day off, followed by one day of training, followed by another day off. Each muscle group is trained every fifth day. Because you don’t train on the same days each week, you’ll need a very flexible schedule to pull this one off.
You can also take the upper/lower split and use it to work each muscle group three times over a 7-day period. This way, you train for two days followed by one day off, and just keep repeating the process.
Day 1: Lower Body
Day 2: Upper Body
Day 3: Off
Day 4: Lower Body
Day 5: Upper Body
Day 6: Off
The higher frequency of training works well if you have the capacity to recover from the stresses of training five days a week for two weeks out of every three. Not everyone can do it, so approach with caution.
Beginners wanting to know how to build muscle are often told to avoid split routines and stick with full-body workouts that involve working each muscle group three times per week.
But as long as their training program and diet are set up correctly, beginners can still make good progress on split routines that involve training 4-5 days per week.
In one Baylor University study, a group of beginners gained 12 pounds of muscle in just 10 weeks using a 4-day split routine .
A 12-week trial, this time using untrained beginners on a 5-day split routine, shows that guys using milk as a post-exercise supplement gained almost nine pounds of muscle with no additional fat .
In much the same way that beginners can make impressive gains using a split routine, anyone who has moved past the beginner stages of training can still add a substantial amount of size by working their whole body three times a week.
University of Alabama researchers, for example, found that a group of men who’d been lifting weights for several years gained almost 10 pounds of muscle on a full-body routine performed three days per week for three months .
How Many Sets Should You Do to Build Muscle?
As far as sets go, there is a “dose-response” relationship between the number of sets you do for a muscle and the speed at which that muscle grows .
In other words, the more sets you do – up to a point at least – the faster your muscles will grow. However, there is a point at which doing more sets becomes counterproductive.
Ten sets per muscle group per week may be twice as effective as five sets. But, it doesn’t necessarily follow that 20 sets is going to be twice as good as 10.
In other words, there’s a theoretical “optimal” number of sets per muscle group, above and below which gains in size will be slower than they otherwise would be.
Training volume only counts when it is stimulating. If your overall training volume is too high, your muscles won’t respond to it and you’ll end up going backwards.
The precise location of this “sweet spot” will depend on your genetics, the length of time you’ve been training, your age, the type of exercises you’re doing, your diet, as well as other sources of stress, be they physical or psychological, that you have going on in your life.
As a rough guide, 10-12 sets per muscle group per week is a good starting point. Then, you can adjust the number of sets upwards or downwards based on how your body responds.
Any increase in weekly training volume should be done gradually. Just add a set or two each week.
Don’t go crazy and start doubling or tripling your training volume overnight. Do it gradually, notice the way your body responds to the increase in volume, and adjust things based on that response.
Heavy Weights or High Reps: What Builds the Most Muscle?
When it comes to reps, conventional wisdom has it that training with light weights and high reps builds muscular endurance, but makes little contribution to gains in size.
Heavy weights and lower reps has long been the accepted “best way” to build muscle.
That’s because lifting heavy weights places tension on a large number of muscle fibers, which in turn sends the “make me bigger” signal to those fibers.
However, lifting heavy weights isn’t the only way to put a large number of muscle fibers under tension.
Training with lighter weights and higher reps – where you “go for the burn” and your muscles feel like they’re pumped up and about to explode – generates a large amount of metabolic stress, which has also been shown to increase the activation of muscle fibers .
In fact, there’s plenty of research out there to show that lighter weights and higher reps do a surprisingly good job at stimulating muscle growth.
In a study from Canada’s McMaster University, sets of 30-40 reps stimulated just as much muscle growth as sets of 10-12 reps .
And this isn’t a finding that’s limited to untrained beginners, who tend to grow no matter what they do.
Even in guys with an average of four years training behind them, researchers found no significant difference in muscle growth after 12 weeks of training with sets of 20-25 reps versus sets of 8-12 reps .
That said, the fact that it’s possible to build muscle with higher reps and lighter weights doesn’t necessarily mean that it’s a good idea to do so.
Remember, higher reps and lighter weights didn’t lead to superior gains in size or strength. But each set took twice as long to complete.
Training to failure in a higher rep range is also highly unpleasant and extremely painful – a lot harder than lower reps and heavier weights.
Plus, lower reps and heavier weights still win the day as far as gains in strength are concerned .
But to repeat, as long as you train hard and push yourself, heavy weights, medium weights and light weights can all be used successfully to build muscle.
How to Build Muscle: Progressive Overload
No matter how many sets and reps you do, it’s important to train hard and focus on improving your workout performance over time.
What exactly do I mean by that?
According to popular legend, Milo of Crotona began carrying a young calf on his shoulders each day.
The story goes that he would pick the calf up and walk around a large stadium. As the animal grew, Milo also grew stronger.
Eventually, he was able to carry a fully-grown bull.
And so, the concept of gradual progressive overload was born. It refers to the idea that you need to increase the demands you impose on your body if you want your muscles to grow.
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.
That’s because 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, a muscle will grow in direct proportion to the amount of work it’s required to do. And while there are many ways to increase muscular work over time, these are the three that I recommend to most people, most of the time.
The most common method of progressive overload involves adding weight while keeping the number of repetitions per set the same. Example:
Workout 1: 8 repetitions with 100 pounds
Workout 2: 8 repetitions with 102.5 pounds
Workout 3: 8 repetitions with 105 pounds
That doesn’t mean there’s a perfectly linear relationship between gains in strength and gains in size. If you double your strength in every exercise, you’re not going to double your muscle mass. Nor does it follow that increasing the size of a muscle by 100% will produce an equal gain in strength.
The biggest guys aren’t always the strongest, and the strongest guys aren’t always the biggest. But it’s rare to see an extremely muscular guy who doesn’t also possess a very high level of strength.
Option two involves doing more repetitions with the same weight. Example:
Workout 1: 6 repetitions with 100 pounds
Workout 2: 7 repetitions with 100 pounds
Workout 3: 8 repetitions with 100 pounds
Let’s say that your current routine involves 3 sets of 8-12 repetitions of a particular exercise.
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. If you can’t, carry on using the same weight until you do.
The third option is to increase your training volume. The most popular way to do so is to perform more sets for each muscle group. Example:
Week 1: 8 sets per muscle group per week
Week 2: 10 sets per muscle group per week
Week 3: 12 sets per muscle group per week
For reasons I’ll explain in a moment, you can’t keep adding sets indefinitely and expect to keep growing. If your training volume is too high, you’ll end up hurting your gains.
As time goes by, and you close in on the upper limit of muscle mass your body is capable of adding, the speed at which you improve will slow down. Progress will come not from workout to workout, but from week to week, and then from month to month.
You’re not going to make progress in every single workout. To do so indefinitely would be impossible, and 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.
What’s more, an effective training program will involve a planned and deliberate reduction in sets, reps and weight. Think of it like taking one step back in order to take two steps forward.
However, your focus should always be on improving your workout performance over time. You need to give your muscles a reason to get bigger, or you’ll remain stuck at the same size you are right now.
If you’re feeling mentally and physically fresh, motivated and hungry to train, and you’re making progress in the gym, you are on a path that will ultimately lead to more muscle.
Should You Go Fast or Slow to Grow?
How fast (or slowly) should you perform each repetition?
With very few exceptions, extremely slow training speeds offer no significant advantage compared to simply lifting and lowering the weight under control .
Take a look at the video below, which shows Ben Bruno performing the trap bar deadlift.
Despite the fact that he appears to be lifting the bar relatively slowly, he’s actually trying to move it as fast as possible. It’s the amount of weight he’s using that slows each repetition down.
If Ben was to use an intentionally slow lifting speed (as opposed to an unintentional one, where the weight you’re lifting and/or muscle fatigue is responsible for slowing you down) the bar wouldn’t come off the ground at all. The only way he can move such a heavy weight is by attempting to do so quickly.
That being said, some exercises are better suited to faster lifting speeds than others. You wouldn’t want to do dumbbell curls with a fast lifting speed, and a clean isn’t really a clean if you’re lifting the bar slowly.
Bodyweight movements such as dips, push-ups, inverted rows and chins, as well as most single-joint exercises, are better done at a slightly slower speed.
But for pretty much every other exercise, the proper rep speed for gaining size is to lift the bar with as much force as you can. Then simply lower it under control.
There is no need to count the number of seconds it takes to complete each repetition, memorize four-digit tempo codes, or calculate your time under tension. Just focus on moving the bar from point A to point B, under control, and forget about everything else.
How Long Should You Rest Between Sets?
The research on this subject is a bit of a mixed bag.
Shorter rest periods (60 seconds) also appear to blunt post-exercise muscle protein synthesis compared to rest periods lasting 5 minutes .
So, what should you do?
Other than saving time, shorter rest periods offer no muscle building advantage over long rest periods. In some cases, they may well put the brakes on muscle growth. If in doubt, err on the side of giving yourself too much rest rather than not enough.
As a rule, I’d suggest taking several minutes of rest between sets of multi-joint exercises that work a large amount of muscle mass, such as squats, rows, deadlifts, leg presses and so on. You can take a shorter rest between single-joint exercises, such as dumbbell curls, lateral raises and pressdowns.
Does Muscle Damage Mean Muscle Growth?
It’s often said that muscle growth is the result of muscle damage.
“Building new muscle is all about damaging the fibers that you start with,” writes one trainer. “It’s your body’s response to the muscle damage you inflict during a workout that leads to muscle growth.”
Blitz and bomb your muscles with lots of sets, and you’ll create an apocalyptic level of damage. The more damage you create, the better. As a result, the muscle will adapt by making itself bigger and stronger.
Or so the theory goes anyway.
Bombing your muscles into submission seems like a highly effective way to train, mainly because it leaves you feeling sore the next day.
It “feels” like it’s working.
However, there’s a surprising lack of research to show that an increase in muscle damage leads to a corresponding increase in muscle growth.
Nor is there any proven link between soreness and growth, and no rule that says you have to annihilate each muscle group in order to make it grow .
In fact, an increase in muscle soreness doesn’t necessarily reflect an increase in muscle damage, and a decrease in muscle soreness is not always indicative of less muscle damage.
That said, while muscle damage isn’t a requirement for growth, it may accelerate the process.
But even then, more damage won’t automatically mean faster growth.
If a link between muscle damage and muscle growth does exist, there’s likely going to be a sweet spot found somewhere between “too much” and “not enough” damage.
In other words, there’s going to be an optimal amount of damage, above and below which your gains will be slower than they otherwise would be.
Despite this, there are plenty of people out there who see soreness as the objective. If my muscles are sore, they think to themselves, the workout must have been a good one.
A training session that forms part of a program designed to stimulate muscle growth will sometimes leave you feeling sore the next day. But that very same training program will sometimes include workouts that do not produce the same level of soreness.
Although feeling sore and stiff for days might be oddly satisfying, it’s no guarantee that muscle is going to be built any faster.
Plan Your Workouts in Advance
You’ll also need to get into the habit of planning your workouts in advance.
Before you even set foot in the gym it’s vital that you know exactly what you’re doing when you get there. If you’re serious about gaining muscle, just “winging it” won’t be good enough anymore. That’s why I highly recommend keeping a training diary.
Probably the most important benefit of a training diary, and the single biggest reason why most people don’t use one, is that it will force you to face facts.
Is what you’re doing delivering results? Or are you doing nothing more than simply repeating the same workout over and over again in the hope that it’ll suddenly start working?
Variety for Your Mind, Consistency for Your Muscles
Once you have a decent training and nutrition program set up, the best way to build muscle as fast as humanly possible is to stick with it.
Frequently I read that you should keep changing your routine every few weeks to “confuse” your muscles and make them grow.
For most people, this is a mistake. There is no point in variety for the sake of variety, and the best way to make absolutely no progress at all is to keep jumping around from one routine to the next. Don’t let anyone try to kid you otherwise.
Shawn Phillips put it best when he said that while variety stimulates the mind, it’s consistency that stimulates the muscles. A training program built around a handful of basic exercises will always work well as long as it’s progressed in the right way.
Rather than constantly changing exercises or routines, I think you’re a lot better off varying the number of reps you do.
In one study, subjects lifted weights three times a week using either a constant or varied training program .
The constant group kept their training program the same, doing 8-12 reps on every set. The varied group changed both the weight and the number of reps, switching from heavy (2-4 reps) to medium (8-12 reps) to light (20-30 reps) on days one, two and three, respectively.
While both groups gained muscle and got stronger, it was the varied group that saw the best results.
There is a time and a place for rotating exercises, but only if it’s part of a structured plan designed to achieve a specific goal. Performing a bunch of random exercises in every workout serves little purpose if you want to get bigger and stronger.
Doesn’t it get boring to use the same exercises all the time?
Nothing beats boredom like the feeling that you are moving closer to your goals. When you’re seeing results, getting “bored” with your workouts is rarely a problem. The people who get bored are usually the ones who aren’t making a great deal of progress.
Finally, forget about your body type or your genetics. You can’t change them, so there’s no point even thinking about them.
Gains in muscle size come slowly, so you’re not going to notice them on a daily or even a weekly basis. But they all add up. Train hard, stick to the plan, and in a few months time you will have more muscle than you have right now.
SEE ALSO: THE MUSCLE BUILDING CHEAT SHEET
If you're fed up spending hours in the gym with nothing to show for it, then check out The Muscle Building Cheat Sheet.
It's a "cut the waffle and just tell me what to do” PDF that tells you exactly how to go about building muscle. To get a copy of the cheat sheet sent to you, please click or tap here to enter your email address.
ABOUT THE AUTHORChristian Finn is the nation’s leading authority on science-based, joint-friendly ways to build muscle. A former "trainer to the trainers," he holds a masters degree in exercise science, and has been featured in or contributed to major media on two continents, including the BBC and Sunday Times in the U.K. and Men’s Health and Men’s Fitness in the U.S.