How many reps to build muscle?

How many reps to build muscles?

When I first started to work out I used to ask myself questions, how many reps do I need to do to build muscle? Should I do 8 reps, should I do 5 reps or should I do 20 reps in order to build muscle? Do different rep ranges produce different results? Is one better than the other?

Different rep ranges will produce different adaptive response depending on whether the load is neural or metabolic factors.  It is called the NEURAL METABOLIC CONTINUUM, the basis of any training programme.

So how  many reps does it take to build muscle?

Training in the low reps of 3-5 which are around the 90-120% of the 1 rep maximum the adaptations are mostly neurological.  That means your CNS (central nervous system) becomes more efficient in its ability to produce more muscle fibers.

To build muscles you need to be training in all the rep ranges in order to produce the best results.

With low reps you tend to get stronger rather than bigger.  The muscles and other cell structures inside the body do not hypertrophy.

Here it is, how many reps to build muscles..

Training in the rep ranges of 6-12 the adaptations are more metabolic and cellular but not so much neurological.

That’s why you see a lot of bodybuilders training in the 9-12 rep ranges because you get bigger and stronger but their strength gains are minimal. This is where you want to train if size is your number one concern and strength gains are not so important.

Training with higher reps (13-20+), the adaptations are mostly metabolic, cellular and vascular. This rep range is designed to produce muscular endurance, a bit of hypertrophy in certain cellular components such as the mitochondria and the capillaries, but very little strength gains.

Training in this range will work your type I muscle fibres. These are your endurance fibres.

Rep Ranges% of 1 rep maxTraining effectDesired goal
1-5 reps85-100%NeuralStrength & Power, little hypertrophy
6-8 reps75-85%Neural 1st, metabolic 2ndStrength 1st, hypertrophy 2nd
9-12 reps70-75%Metabolic 1st, neural 2ndHypertrophy 1st, strength 2nd
13-20 reps+60-70%MetabolicLocal endurance, some hypertrophy, little strength


There is not a distinct line where neural adaptations end and structural/metabolic adaptations begin; rather it is a continuum,more like shades on a rainbow.

For example, when you train in the 6-8 rep range, the adaptations are still somewhat neural, but also metabolic/structural: In this rep range, you get excellent strength gains and also excellent hypertrophy. In the 8-12 rep range, there is still some neural adaptation, but less than the 6-8 range and much less than the 3-5 range

Without boring you with complex biology lessons, our muscle cells are the same as the other cells across the body and they all take up space.  I am sure most of you have heard about the mitochondria (where are those biology text books)?  This is the cell where the energy production takes place.

Myofibrillar hypertrophy (enlargement) (from myofibrils the actual muscle fibres themselves) is caused most effectively in the 6-8 rep range. This contributes to the most visible increases in muscle mass and cross sectional width. However, that doesn’t mean you should only train in the 6-8 rep range. If you want to make the other “stuff” in the muscle cell grow as well, you should train in all rep ranges.

The mitochondria and sarcoplasm also take up a substantial amount of space in the muscle cell and they are best stimulated with high reps. High rep training can also stimulate increased capillarization in the muscle.

You also have more than 1 muscle fibres, there are actually 3, type I, type IIa, and type IIb.  Each one is stimulated differently using different rep ranges.

The take home message is periodization guys.  That means not only changing your programme but also the rep ranges as your bodies adapt.  Our bodies never want to be out of its comfort zone it likes to in homeostasis.   Changing your programme every 6 weeks or so will suffice.

We will talk about periodization in more detail another time as it needs an article devoted to it but for now just a brief outline of what it means.

There are a number of ways to periodize your programme, but the key is to train in ALL the phases rather than just one but not spend so long so to de-train in the other phases.

By training in all the phases throughout the year you will experience tremendous gains, you are literally unlocking the door to a whole new world of new muscle growth

As I said this is for another topic all together.


About the author


Hi, my name is Marwan and I set up this site to help skinny guys and girls just like you to end their frustrations and have the body of their dreams. I believe there are no limitations to what mankind can achieve.