There are two main reasons why people go to the gym, to lose weight or to build muscle (either strength or size).
In this article we will be concentrating on the latter.
Building muscle is a complicated subject, and there is a lot of advice thrown about on the internet and in gyms.
There are diet considerations, sleep, recovery, exercise selection, age, gender, and hormonal issues, time management, programming, and hundreds of other factors that can influence muscle growth.
This article is going to look at rep ranges. A really interesting subject, that always brings a great deal of debate between fitness experts and amateurs.
We will take a look at the differences between strength and hypertrophy, the optimal rep range for strength, the optimal rep range for hypertrophy, the optimal rep range for muscular endurance, other considerations (outlined above) and hopefully by the end of the article you will have a great idea of what it is you need to do.
Strength Vs Hypertrophy
The first thing that you need to decide when you are creating a training program is whether to concentrate on building strength or increasing hypertrophy (increasing muscle size).
When you start out it is certainly possible to do both, but after a while you will need to pick which you are going to train for.
If this doesn’t make sense then compare it to running.
If you had never run before in your life, then the first time you managed it would technically be the furthest and the fastest that you had ever run.
Over the next few weeks your speed would increase as would your endurance. But after a while you would have to concentrate on either running further or running faster, because you couldn’t do both indefinitely.
That’s why you get dedicated sprinters, and dedicated marathon runners. It’s the same thing with lifting.
If you are looking to increase strength, then you are going to be aiming to lift the heaviest weights possible across a number of exercises.
There is a certain rep range that suits this. If you don’t worry too much about lifting the heaviest weight possible, and are more interested in what your muscles look like after then there are rep ranges to suit that too.
Luckily this article is going to cover both, and muscular endurance too!
Optimal Rep Range for Strength Training
The optimal rep range for strength training is a tricky subject, most strength training programs look to help people peak at a certain time, and utilise pyramid training to do so.
Because of this, the rep range starts relatively high, and slowly lowers over time. You can see a training program with 8-12 reps at first (or even higher), that ends up with 1-2 reps within the last session.
However, the most well respected strength training program out there is the 5×5 program. It’s simple to follow (perform five sets of five reps of certain compound lifts), and the rep range is optimal for building strength.
Optimal Rep Range for Hypertrophy
This one is a little more complicated. Everyone used to believe that the sweet spot for hypertrophy was 8-12 reps, anything less than that only built strength, while anything more only improved your muscular endurance. But this has been conclusively proven to be incorrect.
A study in 2015 by Schoenfeld et al found that low weight and high rep sets were as effective at increasing both strength and hypertrophy as medium weight and rep sets .
Considering that low rep sets can also illicit increases in hypertrophy (provided you work to failure) this demonstrates that there is no perfect rep range for hypertrophy.
In fact, a mix of high rep, low rep, and medium rep sets seems to be a very effective technique.
The trick is to add in training techniques such as drop sets, supersets, back off sets, and giant sets so that you can work the muscles to failure more.
Optimal Rep Range for Muscular Endurance
Not many people train specifically for muscular endurance, but it can have a lot of practical benefits for people who play sports, or have manually intensive jobs.
As you have probably guessed the optimal rep range for someone looking to increase muscular endurance is going to be very high. You are looking at a 20-30 rep set!
You can use other techniques to increase muscular endurance though, a back off set is perfect for this.
In a back off set you would perform your usual amount of sets and reps (let’s say 3 sets of 10 reps on bench press).
Afterwards, you would have a 3 minute rest and you would lower the weight to 50% of the previous one. Then you would perform as many reps (using perfect form) as you can until muscular failure.
Not only would this increase hypertrophy, but it massively increases muscular endurance – without the need to perform multiple high rep sets .
To reach optimal muscle growth you need to be consuming enough protein, without it your muscles will not be able to perform muscle protein synthesis.
You also need to have normal levels of testosterone and growth hormone (both of which can be lowered by an unhealthy lifestyle).
You need to be consistently getting 8 hours of high quality sleep, and you want to be eating enough calories to maintain a surplus. The extra calories will be required to create new muscle fibres for bigger strength and hypertrophy gains.
While we have hopefully helped you find the correct rep range for your needs, the true aim of this article is to impress on you just how many factors there are affecting muscle growth.
Without each one, you will never get the results you desire.
One thing that trumps everything though is consistency and application. Turn up to that gym, day in and day out for a long period of time and you will get excellent results.
 Schoenfeld, B., Peterson, M., Ogborn, D., Contreras, B., Sonmez, G. 2015. Effects of low- versus high-load resistance training on muscle strength and hypertrophy in well-trained men. The Journal of Strength & Conditioning 29(10): 2954-2963
 Goto, K., Nagasawa, M., Yanagisawa, O., Kizuka, T., Ishii, N., Takamatsu, K. 2004. Muscular adaptations to combinations of high- and low-intensity resistance exercises. The Journal of Strength & Conditioning Research 18(4): 730-737