What 22 studies say about the best way to build muscle Part 1
You want to know the best way to build muscle in the shortest possible time, but you're confused by all the conflicting information about the best way to do it.
One article says you should do 6 to 12 reps per set, while another says you're far better off doing 4 to 6 reps per set.
Expert A says you should train different muscles on different days, while expert B says you should train the whole body three times a week.
You read a few articles and think you now know how to proceed. Then you read something that says exactly the opposite. You're bombarded with conflicting advice from all sides and you just don't know who to believe and who not to believe.
The good news is that scientists have put many popular and widely held ideas about muscle growth to the test, ranging from the frequency with which you should train a muscle to the amount of time you should rest between sets.
This research shows that some of the advice that has been circulating for years has been proven right, while others have been proven completely wrong. So let's dig a little deeper and take a closer look at what science has to tell us about muscles and muscle building.
How often should you train a muscle per week?
First, we have the question of how often each muscle group should be trained. Some say that the best way to build muscle is to bombard your muscles once a week with lots of exercises, sets and reps.
A typical workout program might include chest workouts on Monday, back workouts on Tuesday, shoulder workouts on Wednesday, leg workouts on Thursday and arm workouts on Friday. While some people get decent results with this type of program, there are better options.
In fact, some studies have shown that training a muscle more often can increase the rate of muscle growth. In one study, subjects who trained a muscle three times a week were able to build muscle faster than subjects who trained that muscle only once a week (1).
When a team of scientists compared studies that compared training muscle groups once, twice or three times a week, they concluded that the larger muscle groups should be trained at least twice a week to maximize muscle growth (2).
Why is training a muscle twice a week a better way to build muscle than training a muscle only once a week?
Protein synthesis - a key driving force behind muscle growth - is increased for a day or two after training, but drops back to baseline a few days later (3). And simply generating more muscle damage doesn't seem to make this increase in protein synthesis last any longer (4).
In addition, the increase in protein synthesis rate peaks faster in trained individuals than in untrained individuals and also declines back to baseline faster in trained individuals (5). The result of this is that there is less overall change in muscle protein synthesis in advanced strength athletes.
In other words, if you train your muscles once a week, they will indeed spend a few days growing after the training session. However, if you let a whole week go by before you train those muscles again, you'll miss several opportunities to stimulate growth (6).
So how often should you train one muscle per week?
To build muscle as quickly as possible, you should train each muscle two to three times a week. If you have a few years of training experience or want to focus on getting certain muscles to grow faster, then training these muscles four times a week can also be very effective.
The first option is to train your whole body twice a week:
- Monday: full body workout
- Tuesday: no training
- Wednesday: no training
- Thursday: full body workout
- Friday: no training
- Saturday: no training
- Sunday: no training
I know that two workouts a week doesn't sound like much, but as long as your training program is set up correctly, you can still make useful progress with just two workouts a week.
In fact, when Canadian scientists compared the same amount of training split between two or three weekly workouts, they found that the gains in strength and muscle mass were almost identical for both training programs (7).
Option two is to train your whole body three times a week on non-consecutive days such as Monday, Wednesday and Friday; Tuesday, Thursday and Saturday; or Wednesday, Friday and Sunday:
- Monday: full body workout
- Tuesday: no training
- Wednesday: full body workout
- Thursday: no training
- Friday: full body workout
- Saturday: no training
- Sunday: no training
If you are able to train 4 to 5 days a week, the number of effective training programs will be much greater. Training more often means that you can divide your body into two or three separate areas while still training each muscle group twice a week or more.
Option three is to train four days a week using a lower body/upper body split. You train the upper body on Monday, the lower body on Tuesday and take Wednesday as a day off. The next upper body workout follows on Thursday, you train your lower body on Friday and then have a training-free weekend. Each muscle group is trained twice a week. Of all the training splits I've used over the years, this is my favorite.
- Monday: Upper body
- Tuesday: lower body
- Wednesday: no training
- Thursday: upper body
- Friday: lower body
- Saturday: no training
- Sunday: no training
The fourth option is something called a pull/push/legs split. You train either four or five days a week, doing the push exercises (chest, shoulders and triceps) on Monday and the pull exercises (back and biceps) on Tuesday.
You then take a training-free day before training your legs on Thursday, followed by another training-free day. On Saturday you start again from the beginning and perform the training session with the press exercises.
- Day 1: Chest, shoulders, triceps
- Day 2: back, biceps
- Day 3: no training
- Day 4: legs
- Day 5: no training
So you train on two days in a row, followed by a non-training day, followed by another training day, followed by a non-training day. Each muscle group is trained once every 5 days. Since you do not train on the same days every week, you must have a flexible schedule for this option.
You can also use the upper body/lower body split to train each muscle group twice every 6 days. Here you train two days in a row, followed by a non-training day and then repeat the process again.
- Day 1: Lower body
- Day 2: upper body
- Day 3: no training
- Day 4: lower body
- Day 5: upper body
- Day 6: no training
The higher frequency of training works well if you have the capacity to recover from the stress of training five days a week for two out of three weeks. Not everyone can cope with this, so this approach should be used with caution.
It is often said that beginners should avoid split programs and stick to full body training programs where each muscle group is trained three times a week
However, as long as the training program and diet are properly designed, beginners can achieve good results with split programs that include training 4 to 5 days per week.
In a study conducted at Baylor University, a group of beginners were able to gain 12 pounds of muscle in just 10 weeks using a 4-day split program (8).
A 12-week study of untrained beginners on a 5-day split program showed that subjects who used milk as a post-workout drink were able to gain nearly 9 pounds of muscle with no additional fat gain (9).
Just as beginners can make impressive gains using split programs, anyone once past the beginner stage can continue to build substantial amounts of muscle mass with three full-body workouts per week.
Researchers at the University of Alabama, for example, found that a group of men with several years of weight training experience were able to gain nearly 10 pounds of muscle in three months using a full-body training program of three training days per week (10).
How many sets should you do?
When it comes to the number of sets, there is something of a 'dose-dependent' relationship between the number of sets you perform for a muscle and the rate at which a muscle grows (11).
In other words, the more sets you perform, the faster your muscles will grow - at least up to a certain point. However, there is a point at which performing 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 will be twice as good as 10 sets.
In other words, there is such a thing as a theoretical "optimal" number of sets per muscle group, above and below which gains will be slower than they could be.
However, training volume only counts if it is stimulating. If your overall training volume is too high, then your muscles will not respond to your training and you will end up regressing.
The exact optimal amount of sets will depend on your genetic makeup, the length of time you've been training, your age, the type of exercises you perform, your diet, and other sources of stress in your life - whether physical or mental.
However, as a rough guide, 10 to 12 sets per muscle group per week is a good starting point. From here, you can adjust the number of your training sets up or down based on how your body responds.
Any increase in weekly training volume should be gradual. Increase the volume by just one or two sets per week and don't start doubling or tripling your training volume overnight. Do this gradually, pay attention to how your body responds to the increase in volume and adjust things based on that response.
High or low reps for muscle growth?
When it comes to repetitions, the conventional wisdom is that training with light weights and high reps builds muscle endurance but contributes little to gains in muscle mass. Heavy weights and low repetitions have long been considered the best way to build muscle.
This is because heavy weights put a greater number of muscle fibers under tension, which in turn gives these fibers the signal to grow. However, training with heavy weights is not the only way to put a large number of muscle fibers under tension.
Training with lighter weights and higher reps, where you're aiming for a muscle burn and where your muscles feel pumped up as if they're about to explode, generates large amounts of metabolic stress, which has been shown to increase muscle fiber activation (12).
In fact, there is plenty of scientific research showing that lighter weights and higher repetitions do a surprisingly good job of stimulating muscle growth.
In a study conducted at McMaster University in Canada, sets of 30 to 40 repetitions stimulated just as much muscle growth as sets of 10 to 12 repetitions (13).
And these are not results that are limited to untrained beginners, who tend to build muscle regardless of what they do. Even among exercisers with an average of four years of training experience, researchers have not observed a difference in muscle growth between 12 weeks of training with sets of 20 to 25 repetitions and 12 weeks of training with sets of 8 to 12 repetitions (14).
However, the fact that it is possible to build muscle with higher repetitions and lighter weights does not necessarily mean that it is a good idea to do so.
Remember that high reps and lighter weights didn't lead to superior gains - but each set lasted twice as long. Furthermore, training to muscle failure with higher reps is highly uncomfortable and extremely painful - and much harder than lower reps with heavier weights.
In addition to this, lower reps with heavier weights are clearly superior in terms of strength gains (15).
However, as long as you train hard and push yourself to your limits, heavy, medium and light weights can all be used to successfully build muscle.
In the second part of this article I will talk about the crucial importance of progression, ideal repetition speed, length of rest between sets, muscle damage & soreness and the need for good training planning and consistency.