Everyone seems to have different thoughts on the matter of "how many reps is best" when you want to build muscle mass. If you ask 10 different people in the gym what they think is an ideal rep range, I wouldn't be surprised if you got 10 different answers.
If it seems to you now that there isn't a right answer to this question, then you will be pleasantly surprised to hear that there is an answer backed by science if you're a "hard-gainer" and you're after maximum muscle gains.
This article will help you by revealing to you what the ideal rep range is, and more importantly why this is so.
The amount of reps you perform in your weight lifting sets will dictate what type of results you get from your training. Doing a low amount of reps is the most effective way to build muscle, period. Higher rep ranges won't stimulate your muscles as well for muscle growth, and are more suited to gain muscle endurance with only a little bit of muscle gain.
But you want the biggest and best muscle gains possible, so low reps are the way to go. So how many reps is ideal for results?
5 - 7 reps.
Performing 5-7 reps per set has been proven to be the most effective range for muscle stimulation and growth. So this means you need to use a weight that is challenging for you to reach 5, 6 or 7 repetitions.
If you are able to do more than 7 reps on a particular exercise then you need to increase the weight, and on the other hand if you can't reach the 5th rep you need to lower the weight a little bit.
So put simply, if you can do more or less than 5-7 reps on one of your lifts, you don't alter how many reps you do. What you change is the amount of weight you lift so that you fall back into that effective 5 to 7 range.
Why 5-7 Reps Is Ideal
There are a few solid reasons as to why 5 to 7 reps is a great rep range to use in your workouts to build muscle.
Firstly, doing less reps in each set will allow you to use all of your energy and strength in those reps. The more reps you do then the more you will lose focus on performing them with everything you've got. Using a low rep range will cause the most muscle growth because you are training as hard as you possibly can, with the heaviest weight that you can use.
More importantly though, a lower rep range is proven to be better for muscle growth thanks to some basic human biology. There are two main types of muscle fibers in your body, slow twitch fibers and fast twitch fibers.
Slow twitch fibers are used the most during endurance type exercise, but they don't have a lot of growing capability. On the other hand, the body taps into fast twitch fibers for shorter and more intense movements. Fast twitch fibers have much more capability for gains in muscle size and strength than slow twitch fibers have.
You see where I'm getting with this? Using low reps such as 5-7 will use the most fast twitch fibers because for these reps you need a short burst of immense energy to perform them. That's what you want, the most fast twitch fibers utilized in your workouts. This is sure to cause the most muscle growth possible.
On top of all that, there's another good reason why 5-7 reps is ideal. Using this amount of reps for your sets will decrease lactic acid secretion in your muscles. Lactic acid is metabolic waste produced by the body, and the less of it you produce in your muscles the better.
5-7 Reps For All Exercises?
Should you stick to the rule of using 5-7 reps for every single exercise you perform? No, there are some exceptions. For example, the following exercises should be done with a higher rep range: abs, forearms, calves, and upper traps. How many reps is effective for these exercises?
I would highly recommend using perhaps 10-12 reps for these particular muscle groups. This is because they're mostly made up of slow twitch fibers, so you will need to use slightly more reps to stimulate them fully. But this applies only to the muscle groups I have listed, all your other exercises will build more muscle with 5-7 reps.
Now you understand why 5-7 reps is an ideal rep range to use for your weight training sets. So if you hear the old argument of how many reps you should use for the best muscle gains, you now know the honest and truthful answer.
Although, keep in mind that if someone else uses less or more reps and is seeing results, then that's fine. Everyone is different, and in this article I am simply stating what has worked well for me and many other "hardgainers".
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Whichever path you take, good luck future warrior and remember this: no matter what anyone tells you, your physique destiny is 100% in your own hands. Don't fall victim to the illusion that being a hardgainer or [insert excuse] will hold you back, because it won't if you have smart strategies and stick to them for the long term. You CAN overcome average genetics and become the powerfully strong, highly muscular, super-ripped & healthiest version of yourself. I, along with so many others before me, have done exactly that and it's my wish for you too.
To your success,
Natural Bodybuilding & Health Author Since 2008
Mad-Scientist of Hardgainer-to-Hero Transformations for 12 Years & Counting
Last and Definitely Least: Certified Fitness Instructor (Australia)