How many reps per set should I do to build muscle? 5? 10? 12? 20? Or should I just go really heavy to the point that I can only do 2 or 3 reps per set?
This is a question that I know a lot of you have asked yourselves (or someone else) at some point in your lifting career. Heck, you’re probably still wondering that now.
Normally, I’d tell you that it didn’t matter how many reps you needed to do to build muscle. As long as you’re constantly applying progressive overload and adding more and more weight to your lifts with each session, the number of reps you do isn’t the primary thing you should worry about. Basically I’d tell you that you shouldn’t lift baby weights, but that you should’t lift more than you can handle either.
If you want to get technical, though, there actually is a certain rep range that is optimal for muscle growth. The science behind this can be read here, so if you’re the type of person that has to know everything in detail before you can be convinced, go ahead and check it out. Otherwise, let me summarize it for you.
The Ideal Rep Range For Muscle Growth: 5-8 Reps
Lifting a heavy weight for 2-3 reps is great for improving strength, but not necessarily for stimulating muscle growth. The same goes for lifting light; doing a 20 rep set will provide some tension in the muscles (which is what we’re looking for) but that tension doesn’t happen until late in the set.
The goal when it comes to developing tension in a certain muscle is to get close to 100% muscle fiber recruitment when performing an exercise. Why? Because that’s how muscles grow.
To do that, you need to be performing a certain weight that only allows you to do 5-8 reps. And that “certain weight” that I’m talking about is 80%-85% of your 1-rep max.
Here’s an example:
Bench Press 1-rep max: 315 pounds.
80% to 85% of 1-rep max = 252 to about 268 pounds.
For this example, 80%-85% of the maximum bench press for this person is about 252 to 268 pounds. He should only be able to do 5-8 reps with this max until he starts to struggle.
Full muscle fiber recruitment is achieved from the VERY FIRST rep. Not the 3rd, the 5th, or the 7th, but with the first. You are also maximizing muscle fatigue when performing this rep range and this is what we want. An optimal balance of muscle fiber recruitment and fatigue through the range of 5-8 reps at the intensities of 80%-85% of your max is what we’re striving for.
So Just Do 5 to 8 Reps for Every Exercise?
Not exactly. For some people, they can perform over more than 8 repetitions easily at 85% of their max on some leg movements. The same goes with smaller muscles like your traps.
Also, keep in mind that this does NOT mean you should only work through this rep range. Other rep ranges like 8-12 or 10-12 “work” too for muscle hypertrophy. The 5-8 rep range (in an 80%-85% intensity) is just what’s needed to optimize muscle growth from the very beginning of a set. It also does not mean that you should get all obsessive and technical and figure out what your 1-rep max is for every exercise. Just lift, and if you find yourself feeling a good stretch in the 5-8 rep range then you’re fine. This is why it’s advisable to log your workouts.
I find myself being able to do more than 8 reps sometimes, so I just keep going until I’m truly fatigued. Just because the optimal range is from 5 to 8 doesn’t mean I’ll stop at the 8th rep. What it does mean though is that I need to man up and put on some more weight on the next set or the next workout session.
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