In a world of the fitness trend increasing on social media and so many non certified trainers making suggestions and the typical gym goer offering you training advice, what do you do? Most people train a muscle group directly once a week, this seems to be the fitness fad, is it optimal? 22 studies show it isn’t, even when researched with body builders. Shocking I know!
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 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.
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.
So, let’s dig in and take a closer look at what the science has to say on the subject of muscle and how to build it.
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 . (MAKE NOTE OF THIS!!!!)
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. You will also typically get stronger faster due to the increase in nervous system adaption to exercise patterns and planes of execution. (track weights and log your workouts!!!!!)
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.
This is one of the biggest reasons I am able to stay shredded year round (combined with proper macronutrients for my goals) and achieve decent muscularity as a steroid free athlete. (former chubby boy and with no cardio)
In short, anyone with average genetics who wants to gain as much muscle as they can in the shortest time possible will get better results training each muscle group at least twice every seven days.
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 to train your whole body 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 or utilize the Full Body Training every other day, which would mean you would be training on different days the following week.
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.
This split I found produces slower results and many people end up missing a workout or taking an extra day off, making the gains slower and muscle group frequency less.
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.
I have often used for women a three day per week frequency for Lower Body with higher volume workouts on Monday and Tuesday or have them workout Lower Body on Wednesday with Thursday off and the higher volume, high rep lower body workout on Saturday as a glycogen depletion workout for dinners out or functions where an increase in calories will be consumed. This approach works extremely well for fat loss and maximum lower body sculpting.
Day 1: Lower Body
Day 2: Upper Body
Day 3: Off
Day 4: Lower Body
Day 5: Upper Body
Day 6: Lower Body
It’s often said that beginners should 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?
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.
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, 10-15 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 and the reps per set implemented each workout.
What about reps?
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.
No matter how many sets and reps you do, it’s important to train hard and focus on getting stronger.
Now let’s get to work sculpting the body of your dreams!
Author of Finding Balance 100 meals to Fit Your Life
CEO of FitNSync and Developer of FIT N FLEXIBLE
NCSF Certified Personal Trainer, Nutritional Consultant, Published Fitness Model
Former IFBB World Amateur Natural Fitness Championships Men’s Physique Competitor